EP3864713A2 - Condensateur intégré et procédé pour la fabrication d'un condensateur intégré - Google Patents

Condensateur intégré et procédé pour la fabrication d'un condensateur intégré

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Publication number
EP3864713A2
EP3864713A2 EP19786544.7A EP19786544A EP3864713A2 EP 3864713 A2 EP3864713 A2 EP 3864713A2 EP 19786544 A EP19786544 A EP 19786544A EP 3864713 A2 EP3864713 A2 EP 3864713A2
Authority
EP
European Patent Office
Prior art keywords
layer
dielectric
dielectric layer
layers
integrated capacitor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP19786544.7A
Other languages
German (de)
English (en)
Inventor
Norman Böttcher
Tobias Erlbacher
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV
Original Assignee
Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV filed Critical Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV
Publication of EP3864713A2 publication Critical patent/EP3864713A2/fr
Pending legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G4/00—Fixed capacitors; Processes of their manufacture
    • H01G4/40—Structural combinations of fixed capacitors with other electric elements, the structure mainly consisting of a capacitor, e.g. RC combinations
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
    • H10D1/00—Resistors, capacitors or inductors
    • H10D1/01—Manufacture or treatment
    • H10D1/045—Manufacture or treatment of capacitors having potential barriers, e.g. varactors
    • H10D1/047—Manufacture or treatment of capacitors having potential barriers, e.g. varactors of conductor-insulator-semiconductor capacitors, e.g. trench capacitors
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
    • H10D1/00—Resistors, capacitors or inductors
    • H10D1/60—Capacitors
    • H10D1/62—Capacitors having potential barriers
    • H10D1/66—Conductor-insulator-semiconductor capacitors, e.g. MOS capacitors
    • H10D1/665—Trench conductor-insulator-semiconductor capacitors, e.g. trench MOS capacitors
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
    • H10D1/00—Resistors, capacitors or inductors
    • H10D1/60—Capacitors
    • H10D1/68—Capacitors having no potential barriers

Definitions

  • Exemplary embodiments according to the invention relate to an integrated capacitor and a method for producing an integrated capacitor.
  • Si x N y non-stoichiometric silicon nitride with increased silicon content
  • an integrated capacitor has a first electrode structure, a second electrode structure and an intermediate dielectric layer structure.
  • the dielectric layer structure has e.g. B. on a layer combination with a Si0 2 layer, an Si 3 N 4 layer and a Si x N y layer and the Si x N y layer can have a non-stoichiometric silicon nitride material with an increased silicon content.
  • the dielectric layer structure thus comprises e.g. B. at least three layers, which are arranged parallel to the first electrode structure and the second electrode structure.
  • Non-stoichiometric silicon nitride also called stress-free silicon nitride Si x N y
  • the share of Silicon is e.g. B. higher in relation to nitrogen in non-stoichiometric silicon nitride, which is why it also bears the nickname silicon-rich silicon nitride.
  • the integrated capacitor it can be, for. B. can be a planar plate capacitor or a trench capacitor, wherein very thick layers can be realized by the trench capacitor.
  • This exemplary embodiment of the integrated capacitor is based on the knowledge that very large layer thicknesses can be achieved with non-stoichiometric silicon nitride, since intrinsic stresses in the Si x N y layer compared to intrinsic stresses in the Si 3 N 4 layer (ie stoichiometric silicon nitride) are lower.
  • the layer thickness is defined, for example, as an extension of the Si0 2 layer, the Si 3 N 4 layer and / or the Si x N y layer perpendicular to the parallel contact areas between the individual layers of the dielectric layer structure.
  • the interaction of the Si 3 N 4 layer and the Si x N y layer in the dielectric layer structure is used.
  • a high permittivity of stoichiometric silicon nitride SS 3 N 4 large layer thicknesses and thus a higher dielectric strength of the integrated capacitor can be achieved with a simultaneously higher capacitance compared to capacitors with only silicon dioxide in the dielectric.
  • mechanical stresses that scale with the layer thickness can arise in the production of semiconductor components with stoichiometric silicon nitride SS 3 N, such as the integrated capacitor.
  • z. B. low-stress silicon nitride, ie the Si x N y layer integrated in the dielectric layer structure (z. B. dielectric multilayer stack).
  • the dielectric layer structure has an SiO 2 layer which, according to an exemplary embodiment, can be arranged in the dielectric layer structure in such a way that delamination of the dielectric layer structure from the first electrode structure is at least partially or completely avoided.
  • Si0 2 has very low interface states on silicon and a high electrical load capacity. It should be noted here that the avoidance of delamination is at least partially achieved by using the Si0 2 layer is effected, since this can compensate for stresses caused by nitride layers, but in addition the other layers of the dielectric layer structure also have an influence on the delamination and thus improve the integrated capacitor. Since in a boundary area between the silicon substrate, the z. B.
  • silicon nitride may have the first electrode structure and / or the second electrode structure, and silicon nitride has a density of surface states, according to one embodiment, silicon nitride is used as a dielectric in combination with silicon dioxide as a dielectric separating layer to the silicon substrate.
  • a monolithically integrated capacitor with high dielectric strength and / or high capacitance density can be realized through a combined use of Si 3 N 4 and Si x N y .
  • the advantage arises from a reduction in mechanical stress with a low leakage current through the dielectric layer structure. This enables the realization of less expensive silicon capacitors with significantly increased dielectric strength.
  • the first electrode structure has a semiconductor substrate provided with a trench structure.
  • the electrode structure has e.g. B. rectangular or rounded recesses to which z. B. the dielectric layer structure is arranged. Rectangular or rounded recesses mean z. B. rectangular within a sectional view through the integrated capacitor, the sectional view being arranged parallel to the layer thickness of the layers of the dielectric layer structure.
  • the first electrode structure has e.g. B. cylindrical and / or cuboidal recesses.
  • the trench structure is e.g. B. arranged facing the second electrode structure.
  • the trench structure of the first electrode structure can have recesses or openings which face the second electrode structure and are arranged hexagonally, as a result of which the capacitance value of the integrated capacitor can be increased further.
  • the first electrode structure forms a rear side electrode which is arranged on a rear side contact; and the second electrode structure is a front side electrode arranged on a front side contact.
  • a ratio of silicon and nitrogen in the Si x N y layer is between 0.8 and 1 (e.g. 0.8ix / y ⁇ 1). It should be noted here that the Si x N y - Layer is non-stoichiometric silicon nitride, in which the proportion of silicon in relation to nitrogen can be higher than that of stoichiometric silicon nitride Si 3 N 4 .
  • the ratio of silicon and nitrogen of the Si 3 N 4 layer is 0.75
  • the ratio of silicon and nitrogen of the Si x N y layer should e.g. B. between 0.76 and 1, 5 or between 0.8 and 1.
  • This optimized ratio between silicon and nitrogen in the Si x N y layer reduces bending of the integrated con- densators and delamination of the Dielektrikum fürtechnik of the first and / or second electrode structure. Furthermore, the breakdown voltage of the integrated capacitor is increased by the optimized ratio.
  • the dielectric layer structure has a higher proportion of Si 3 N 4 ! VIateriais than material deviating therefrom. So the dielectric layer structure z. B. more or thicker Si 3 N 4 layers than Si0 2 layers and / or Si x N y layers.
  • This optimized combination of Si 3 N 4 and Si x N y thus advantageously combines the advantages of a low leakage current (of Si 3 N 4 ) and a reduced mechanical stress (due to Si x N y ).
  • it is sufficient to replace a smaller percentage than expected from stress-free nitride Si x N y , since mechanical stress in the dielectric layer structure does not correspond to the sum of the individual mechanical stresses of the individual layers.
  • a thickness of the Si 3 N 4 layer d si3N4 is formed in a ratio n to one to a thickness of the Si x N y layer d si x N y, where n is between 1.5 and 2.5.
  • n is between 1.5 and 2.5.
  • the expansion of the Si 3 N 4 layer, perpendicular to adjacent surfaces of the layers of the dielectric layer structure, and the expansion of the Si x N y layer, perpendicular to adjacent surfaces of the layers of the dielectric layer structure, are here and in the following, for. B. by a thickness of the respective layer.
  • the thickness can be e.g. B. the smallest dimension of three dimensions in the three spatial directions for Act Si 3 N 4 layer and / or the Si x N y layer.
  • This definition can also be applied to thicknesses of other layers of the integrated capacitor described herein, such as e.g. B. on a Si0 2 layer, a substrate, an electrode structure (z. B. front electrode, back electrode), etc.
  • n ⁇ 2 which means that the expansion of the Si x N y layer d sixNy makes up a maximum of 33% of the total thickness of the dielectric layer structure , as a result of which possible leakage currents can be minimized.
  • the Si 3 N layer can have at least two Si 3 N underlayers, which are separated from one another within the dielectric layer structure, such as, for. B. can be arranged on opposite sides of the SixNy layer.
  • a first Si 3 N underlayer can have a first extent perpendicular to adjoining surfaces of the dielectric layer structure and a second Si 3 N 4 underlayer can have a second extent perpendicular to adjoining surfaces of the layers of the dielectric layer structure.
  • the extent of the Si 3 N layer can thus represent a sum of the first extent and the second extent.
  • a thickness of the Si 3 N 4 layer to a thickness of the Si x N y layer is formed in a ratio n to one, where n is between 2 and 2.5, between 2 and 9, between 2 and 15 or between 2 and 32 lies.
  • the expansion of the Si 3 N 4 layer can be a sum of the expansion z. B. all Si 3 N 4 sublayers, perpendicular to adjacent surfaces of the layers of the dielectric layer structure.
  • the Si x N y layer can have a plurality of Si x N y sublayers, and thus the extent of the Si x N y layer can represent a sum of the extent of all SixNy sublayers, perpendicular to adjacent surfaces of the layers of the dielectric layer structure.
  • the ratio reflects the ratio between a sum of all extents of Si 3 N 4 underlayers to extents of all Si x N y underlayers.
  • the Si x N y layer is arranged separately from or not directly on the Si0 2 layer.
  • the Si 3 N 4 layer can be arranged between the Si x N y layer and the SiO 2 layer. If the Si x N y layer is arranged directly on the Si0 2 layer, high intrinsic stresses can occur in the dielectric layer structure, which lead to delamination of the layers.
  • the SixNy layer is arranged separately from or not directly on the Si0 2 layer, a boundary layer between the Si0 2 layer and the Si x N y layer cannot or only partially absorb the stress, so that a Delamination of the layers can be reduced or prevented.
  • Si x N y layers can also be used to achieve a sufficient reduction in stress in order to simultaneously achieve the lowest possible leakage current. May approximate, for example according to one execution, for example, a layer stack of Si 3 N 4 700nm, 200nm and 700nm Si x N y Si x N y may be used. It should be noted here that it can be advantageous if the expansion of the Si x N y layer is significantly less than an expansion of the Si 3 N 4 layers perpendicular to adjacent surfaces of the layers of the dielectric layer structure. Without the Si x N y layer, the production of such thick Si 3 N 4 layers with surface enlargements by hole structures of a factor of 5-15 cannot succeed. It should also be noted that the extent of the Si x N y layer can represent a sum of all the extents of all Si x N y layers (these can also be referred to as Si x N y underlayers).
  • the thickness of the Si x N y layer d sixNy corresponds to at most 33% of the total thickness of all Si x N y layers and Si 3 N 4 layers.
  • the extent of the Si x N y layer corresponds to d si N , perpendicular to adjacent ones
  • Si x N y layer Areas of the layers of the dielectric layer structure, at most 33% of the total expansion of all Si x N y layers and Si 3 N layers, perpendicular to adjacent areas of the layers of the dielectric layer structure.
  • the effect of the Si x N y layer lies in minimizing the influence of mechanical stress (disc bending, delamination, crack formation), whereby the electrical properties (withstand voltage, leakage current, capacitance) are only slightly influenced in comparison to thick layers.
  • the extent of the Si x N y layer d sixNy , perpendicular to adjacent surfaces of the layers of the dielectric layer structure can be at most 1/4, 1/5 or 1/6 of the total extent of all Si x N y layers and Si 3 N layers , perpendicular to adjacent surfaces of the layers correspond to the dielectric layer structure.
  • a thickness of the Si x N y layer corresponds to at most 50% of a total thickness of all Si 3 N 4 layers.
  • an expansion of the Si x N y layer, perpendicular to adjacent surfaces of the layers of the dielectric layer structure, corresponds to at most 50% of a total extent of all Si 3 N layers, perpendicular to adjacent surfaces of the layers of the dielectric layer structure.
  • z. B. d sixNy Q, 5-d si3Ni the thickness of the Si x N y layer may correspond to a lower limit of 1%, 3%, 6%, 8% or 10% of the total extent of all Si 3 N 4 layers.
  • This proportion of stress-free nitride is optimized so that the integrated capacitor withstands high field strengths, has low leakage currents and has high voltage insulation. Leakage currents in particular can be minimized in this way, since a 100% Si x N y layer would lead to very high leakage currents.
  • the dielectric layer structure of the integrated capacitor has a thickness of at least 1200 nm and a dielectric strength of at least 900 V.
  • the dielectric layer structure of the integrated capacitor has an extent, perpendicular to adjoining surfaces of the layers of the dielectric layer structure, of at least 1200 nm, as a result of which the integrated capacitor is designed to be operated at a voltage of at least 900 V. This ensures high dielectric strength. It is e.g. B. permanently prevents that at voltages of at least 900 V, the dielectric layer structure between a front side electrode and a rear side electrode is "struck through".
  • the leakage current remains at at least 900 V below a current density of IOmL / cm 2 (or alternatively below a current density of 11 mA / cm 2 , 9pA / cm 2 or 8pA / cm 2 ).
  • Effective oxide thicknesses are given in Table 1.
  • a minimum effective thickness of 1330 nm for the voltage class of 900 V can mean that the dielectric layer structure has a total thickness of 350 nm of SiO 2 layers and a total thickness of 1500 nm of Si 3 N 4 layers.
  • Typical physical layer thicknesses are at 50V 90nm, at 200V 520nm, at 600V 1300nm and at 900V 1850nm. However, this then also depends heavily on the Si0 2 to SiN ratio of the layer thicknesses.
  • the Si x N y layer has a thickness in a range from 50 nm to 2000 nm, 50 nm to 1000 nm, 50 nm to 500 nm or 100 nm to 1000 nm.
  • a method for producing an integrated capacitor has the step of producing a dielectric layer structure in a trench structure of a semiconductor substrate.
  • the dielectric layer structure has e.g. B. a plurality or a combination of adjacent dielectric layers, at least one of the dielectric layers having Si0 2 material, at least one of the dielectric layers having Si 3 N 4 material, and at least one of the dielectric layers having SS x N y material.
  • the Si x N y material has e.g. B. non-stoichiometric silicon nitride with increased silicon content.
  • the dielectric layer structure has a plurality or a combination of a dielectric layer which has Si0 2 material, a dielectric layer which has Si 3 N 4 material, and a dielectric layer which has Si x N y material.
  • a ratio of silicon and nitrogen in the dielectric layer which has Si x N y material is between 0.8 and 1 (for example 0.8 ⁇ x / y ⁇ 1).
  • the dielectric layer structure has a higher proportion of the Si 3 N 4 material than material deviating therefrom. So the dielectric layer structure z. B. more or thicker dielectric layers that have Si 3 N 4 material than dielectric layers that have Si0 2 material, and / or dielectric layers that have Si x N y material.
  • an expansion d siaN4 of the dielectric layer which has Si 3 N material, is perpendicular to adjacent surfaces of the layers of the dielectric layer structure
  • an expansion d sixNy of the dielectric layer which has Si x N y material, is perpendicular to adjacent surfaces of the Layers of the dielectric layer structure, formed in a ratio n to one, where n is between 1, 5 and 2.5.
  • the dielectric layer which has Si x N y material, is not arranged directly on the Si0 2 layer.
  • methods can be formed in accordance with one of the exemplary embodiments described above.
  • a device can be formed in accordance with one of the exemplary embodiments described above.
  • a manufacturing method can be formed according to one of the exemplary embodiments described above.
  • Figure 1 is a schematic representation of an integrated capacitor, according to an embodiment of the present invention.
  • FIG. 2a shows a schematic illustration of an integrated capacitor with a planar dielectric layer structure which, according to an exemplary embodiment of the present invention, has four layers;
  • Fig. 2b is a schematic representation of an integrated capacitor with a
  • Dielectric layer structure which according to an exemplary embodiment of the present invention has four layers and a trench structure;
  • FIG. 3 shows a schematic illustration of an integrated capacitor which is designed as a trench capacitor in accordance with an exemplary embodiment of the present invention
  • FIG. 4a shows a picture on the scanning electron microscope of a first electrode structure, which has a semiconductor substrate provided with a trench structure, according to an exemplary embodiment of the present invention
  • FIG. 4b shows a picture on the scanning electron microscope of a cross section of an integrated capacitor as a trench capacitor, according to an embodiment of the present invention
  • 5a shows a schematic illustration of a plan view of a trench structure of a semiconductor substrate of a first electrode structure of an integrated capacitor, according to an exemplary embodiment of the present invention
  • 5b shows a schematic illustration of a cross section through a hole structure of a trench structure of a semiconductor substrate and an electrode structure of an integrated capacitor, according to an exemplary embodiment of the present invention
  • 5c shows a schematic equivalent circuit diagram of an integrated capacitor according to an exemplary embodiment of the present invention.
  • 6a shows a diagram of a bending of silicon semiconductor wafers with different hole geometries during the deposition of individual dielectric layers, according to an exemplary embodiment of the present invention
  • FIG. 6b shows a table of the dielectric layer structures, the bending of the silicon semiconductor wafer via the individual deposition processes of the dielectric layer structure in FIG. 6a is shown, according to an exemplary embodiment of the present invention
  • Fig. 7 is a diagram of a capacitance-voltage characteristic of an integrated circuit
  • FIG. 8a shows a diagram of current-voltage characteristic curves of a plurality of integrated capacitors, according to an exemplary embodiment of the present invention, in comparison with a capacitor with a dielectric made of silicon dioxide and exclusively silicon-rich nitride;
  • FIG. 8b shows a table of the dielectric layer structures, of the integrated capacitors, the current-voltage characteristic of which is shown in FIG. 8a, according to an exemplary embodiment of the present invention.
  • FIG. 9 is a block diagram and schematic representation of a sequence of steps for producing an integrated capacitor, according to an exemplary embodiment of the present invention.
  • FIG. 1 shows an exemplary embodiment of an integrated capacitor 100, which has a first electrode structure 110 and a second electrode structure 120. Furthermore, the integrated capacitor 100 has a dielectric layer structure 130 which is arranged between the first electrode structure 110 and the second electrode structure 120.
  • the dielectric layer structure 130 has a layer combination with an Si0 2 layer 132, an Si 3 N 4 layer 134 and an Si x N y layer 136.
  • the SS x N y layer 136 has a non-stoichiometric silicon nitride material with increased silicon content. According to one exemplary embodiment, the silicon content of the Si x N y layer 136 is increased in comparison to the silicon content of the Si 3 N 4 layer 134.
  • the first electrode structure 110 can have a semiconductor substrate.
  • the semiconductor substrate can have p-doped silicon material.
  • the doping of the silicon substrate contributes to a targeted increase in the conductivity.
  • the semiconductor substrate is doped with boron (B), an element of the third main group of the periodic table.
  • the second electrode structure 120 polycrystalline silicon material (polysilicon). It is e.g. B. a highly n-doped polycrystalline silicon. Like the doping of the silicon substrate of the first electrode structure 110, this serves the goal of increasing the conductivity of the high-resistance silicon. For doping, for example, phosphorus and argon, which are elements of the fifth main group of the periodic table, are used.
  • the first electrode structure 110 forms a rear side electrode, which is arranged on a rear side contact
  • the second electrode structure 120 forms a front side electrode, which is arranged on a front side contact.
  • the essence of this invention lies in the use of a dielectric layer stack, ie the dielectric layer structure 130, consisting of a layer combination with a Si0 2 layer 132, a Si 3 N 4 layer 134 and a Si x N y layer 136.
  • the number and order of the partial layers 132 to 136, their layer thickness and the quantitative ratio between silicon and nitrogen (x: y ) in Si x N y have a decisive influence on the manufacturability (in particular reduction of semiconductor wafer bending and delamination) and the electrical properties (in particular increase in breakdown voltage and capacitance density) of the integrated capacitor 100.
  • the SiiSciumdioxid-Si0 2 layer 132 has the advantages of simple manufacture and good insulation properties.
  • the SiO 2 layer 132 is used as a dielectric layer at an interface to the first electrode structure 110, for example due to lower interface states in the dielectric layer structure 130.
  • the silicon dioxide layer 132 is, according to one exemplary embodiment, between the first electrode structure 110 and a silicon nitride layer, such as, for. B. the Si 3 N 4 layer 134 or the Si x N y layer 136 arranged.
  • the Si 3 N 4 layer 134 has stoichiometric silicon nitride Si 3 N with a permittivity of 7.5, as a result of which higher layer thicknesses and thus a higher dielectric strength of the integrated capacitor 100 can be achieved with a simultaneously higher capacitance compared to only silicon dioxide in the dielectric.
  • the stoichiometric ratio of the elements silicon (Si) and nitrogen (N) is three to four.
  • mechanical stresses which scale with the layer thickness occur in the production of semiconductor components with stoichiometric silicon nitride.
  • low-stress silicon nitride Si x N y is integrated into the dielectric layer structure 130.
  • the stress resistance of the integrated capacitor 100 is increased with the aid of the low-stress silicon nitride, since the increase in the thickness of the dielectric leads to the shifting of the dielectric breakdown toward higher voltages.
  • the Si x N y layer 136 has non-stoichiometric silicon nitride material, also called low-stress silicon nitride Si x N y .
  • the non-stoichiometric silicon nitride is composed of a changed ratio of silicon and nitrogen compared to the Si 3 N material. With low-stress silicon nitride, thicker layers can be realized. be because the intrinsic stresses of the layer are lower compared to intrinsic stresses in the stoichiometric silicon nitride.
  • a mechanical stressing of the complete dielectric layer structure 130 is less than a sum of the individual stresses of the individual layers of the dielectric layer structure 130.
  • the disadvantage of the low-stress silicon nitride Si x N y is that its defect density is higher than that of stoichiometric nitride Si 3 N 4 . Due to the higher defect density in the SixNy layer 136, the use of an Si 3 N 4 layer 134 is in contact with the upper electrode; ie the second electrode structure 120, or combinations with thin Si x N y layer 136 in contact with the second electrode structure 120, which have a low leakage current. However, it should be borne in mind that a thicker Si x N y layer 136 e.g. B. leads to a higher leakage current.
  • Si 3 N 4 134 and Si x N y 136 thus allows the advantages of the low leakage current (of Si 3 N 4 layer 134) and the reduced mechanical stress (due to Si x N y layer 136) ) unite.
  • the mechanical stress in the entire layer stack ie in the entire dielectric layer structure 130, does not correspond to the sum of the individual mechanical stresses.
  • the Si x N y layer 136 is arranged separately from or not directly on the SiO 2 layer in order to at least partially avoid delamination of the layers.
  • this also depends on the total thickness of the dielectric layer structure 130 to be realized.
  • B. with a 1000 nm thick Si 3 N layer 134 on a 500 nm thick Si x N y layer 136 is problematic. All thicknesses of layers given herein can be understood as target data. ACTUAL data can deviate from these TARGET data. For example, manufacturing or design-related te deviations of up to 10%, up to 5% or up to 2% of the target data occur.
  • the dielectric layer structure 130 has a higher proportion of an Si 3 N 4 material than the material deviating therefrom.
  • the beispiels- Dielektrikum fürtechnik 130 have more Si 3 N 4 layers 134 and Si0 2 - layer 132 and Si x N y layers 136.
  • the Si 3 N 4 layer 134 thicker Removing be designed as the Si0 2 layer 132 and / or the Si x N y layer 136, with the same extent of the adjoining surfaces of the individual layers.
  • an extent d si3 4 131 2 of the Si 3 N 4 layer 134, perpendicular to adjacent surfaces of the layers of the dielectric layer structure 130, is perpendicular to an extent d sixNy 131 n of the Si x N y layer 136 to adjacent surfaces of the layers of the dielectric layer structure 130, in a ratio N: 1, wherein N is between 1.5 and 2.5.
  • the expansion 131 i to 131 3 perpendicular to adjoining surfaces of the layers of the dielectric layer structure is, for example, the thickness of the individual layers 132 to 136.
  • the thickness 131 2 is the Si 3 N 4 Layer 134 twice the thickness 1311 of the Si x Ny layer 136 or, if the integrated capacitor 100 has a dielectric layer structure 130 with more than the three layers 132 to 136, then a total thickness of all Si 3 N 4 layers 134 be twice the total thickness of all Si x N y layers 136.
  • the surface area can be increased by the first electrode structure 110 having a semiconductor substrate provided with a trench structure.
  • the advantage of the implementation according to the invention is the implementation of monolithically integrated capacitors 100
  • the layer thickness d si N is
  • a minimum layer thickness d sixNy of the Si x N y layer can correspond to a lower limit of the producibility.
  • the following relationship can apply to the layer thickness ratio : 0.03 d Si3Ni ⁇ d sixNy ⁇ 0.5 ⁇ d Si3Ni
  • a surface structure for increasing the surface and the structure of the dielectric layer stack (number and thickness of the partial layers) can be determined by means of a cross-sectional analysis using a scanning electron microscope. For the analysis of the quantitative ratio of silicon and nitrogen and ultimately the order of the sub-layers are
  • the silicon capacitor described is excellently suited as a backup capacitor or damping element for voltage peaks or high-frequency oscillations (RC snubbers) in switching applications with very short switching times.
  • the integrated capacitor 100 can be operated with operating voltages up to 900 V or up to 1200 V by combining the Si 3 N 4 layer 134 and the Si x N y layer 136.
  • FIGS. 2a and 2b each show a schematic illustration of an integrated capacitor 100 according to the invention in accordance with an exemplary embodiment of the present invention.
  • the integrated capacitor 100 in FIGS. 2a and 2b can have the same features and functionalities as the integrated capacitor 100 from FIG. 1, the integrated capacitor 100 from FIGS. 2a and 2b therefore differing from the integrated capacitor from FIG 1 distinguishes that the dielectric layer structure 130 has three instead of two silicon nitride layers 133T to 133 3 in addition to the SiO 2 layer 132.
  • the alternative dielectric layer structure 130 is arranged between the first electrode structure 110 and the second electrode structure 120.
  • the integrated capacitors in FIG. 2a and in FIG. 2b differ in that the integrated capacitor 100 in FIG. 2a can represent a plate capacitor and the integrated capacitor in FIG. 2b a trench capacitor.
  • Dielectrics are characterized by low conductivity and thus a high specific resistance. For the use of the material in a capacitor, a high permittivity leads to a high capacitance value.
  • the breakdown field strength of the dielectric material is a measure of the dielectric strength of the dielectric and thus of the dielectric strength of the capacitor 100.
  • the dielectric is represented by the dielectric layer structure 130 in the integrated capacitor 100.
  • the dielectric of the integrated capacitor 100 according to the invention is thus present as a multilayer system made of different dielectric materials.
  • the silicon dioxide layer 132 is located at an interface to a p-doped silicon substrate (ie the first electrode structure 110 in FIG. 2a or the substrate 11 in FIG. 2b). This is followed by a combination of three layers 133 T to 133 3 , e.g. B. comparable thickness, two silicon nitrides 134, 136.
  • the silicon nitride layers 133 T to 133 3 stoichiometric silicon nitride Si 3 N 4 134 and / or low-stress silicon nitride Si x N y 136, which have different electrical and mechanical properties.
  • the layers 133 T and 133 3 each comprise an Si 3 N 4 layer 134 and the layer 133 2 an Si x N y layer 136.
  • Other two layers of the three layers 133 T to 133 3 represent the Si 3 N 4 layer 134 and a third layer of the three layers 133i to 133 3 represent the Si x N y layer 136.
  • it is z. B. in two of the three silicon nitride layers 133 to 133 3 to Si 3 N 4 layers 134 and in one of the three silicon nitride layers 133 T to 133 3 by a Si x N y layer 136.
  • the first layer 133 T may be a Si 3 N layer 134, the second layer 133 2 a Si x N y layer 136 and the third layer 133 a an Si 3 N 4 layer 134, such as. B. the previously described layer sequence 2 in Table 2.
  • two of the three silicon nitride layers 133T to 133 3 each have an Si x N y layer 136 and one of the three silicon nitride layers 133T to 133 3 has an Si 3 N layer 134, such as, for example, B. the layer sequence 3 described above in Table 2, in which the first silicon nitride layer 133T and the third silicon nitride layer 133 3 have a Si x N y layer 136 and the second silicon nitride layer 133 2 has the Si 3 N 4 layer 134.
  • the dielectric layer structure 130 can have further silicon nitride layers 133 T to 133 3 in order to further increase the thickness of the dielectric of the integrated capacitor 100 and thus also to increase the dielectric strength of the integrated capacitor 100.
  • a first electrode structure 110 of the capacitor 100 has a semiconductor substrate provided with a trench structure. On the surface of the trench structure of the first electrode structure 110, for. B. arranged a dielectric layer structure 130 of the integrated capacitor 100. The dielectric layer structure 130 is thus arranged between the first electrode structure 110 and a second electrode structure 120.
  • the first electrode structure 110 forms a rear side electrode which is arranged on a rear side contact 112 and the second electrode structure 120 forms a front side electrode which is arranged on a front side contact 122.
  • the effective Total thickness d of the dielectric may include the total effective silicon nitride thickness 139 and the effective thickness 131 3 of the SiO 2 layer 132.
  • the integrated capacitor 100 (can also be referred to as a silicon trench capacitor) with the special combination of an Si 3 N 4 layer and an Si x N y layer in the dielectric layer structure 130 provides a concept for operating voltages up to 900 V. or up to 1200 V.
  • the core of the concept is a multi-layer dielectric (ie the dielectric layer structure 130) with at least one layer made of silicon-rich silicon nitride to reduce the mechanical stress.
  • the effective oxide thickness of the dielectric 130 is used to scale the dielectric strength of the capacitor 100 (eg 900 V voltage class).
  • a breakdown voltage U max follows a relationship between the material-specific critical field strength E crit and the given effective oxide thickness d of the dielectric 130:
  • the thickness of the dielectric layer also increases its intrinsic mechanical stress. Due to the specially developed dielectric layer structure 130, the mechanical stress in the capacitor 100 or in the layers of the dielectric layer structure 130 can be kept small when the total thickness 139 is increased, as a result of which during the production of the capacitor 100 severe bending or breakage of the semiconductor substrate or delamination of the dielectric 130 itself can be prevented at least partially.
  • the breakdown voltage of the capacitor 100 is directly proportional to the layer thickness 139 of the dielectric 130, while the capacitance is antiproportional to it - the breakdown voltage and capacitance density behave in opposite directions when dimensioned by d .
  • the special combination of Si 3 N 4 and SixN y effectively reduces mechanical stress.
  • z. B a semiconductor substrate, or a layer of polysilicon, as the electrode 110, 120.
  • FIG 3 is a schematic cross section through an integrated capacitor 100, in which, according to one exemplary embodiment, the trench structure of the first electrode structure 110 is realized by means of rectangular recesses. Even if the dielectric layer structure 130 is shown as a single layer, it can have multiple layers such as an SiO 2 layer, an Si 3 N 4 layer and an Si x N y layer.
  • the capacitor 100 is e.g. B. a silicon capacitor that can be successfully manufactured and characterized with a dielectric strength of 1200 V.
  • the high mechanical loads during processing could be reduced by using low-stress silicon nitride in a dielectric stack, i.e. in the dielectric layer structure 130 can be reduced.
  • stoichiometric and low-stress silicon nitride were converted into a multilayer system, i.e. dielectric layer structure 130, combined from three layers, at least one layer consisting of low-stress silicon nitride.
  • the surface of the capacitors 100 was enlarged using a hexagonal hole structure.
  • all combinations of the layer stacks can be realized with a small hole depth L10 and selected layer stacks with a deeper hole design L20.
  • the different material combinations in the dielectric layer structure 130 have hardly any influence on the capacitance values of the silicon capacitors 100.
  • the capacitance per Area can be increased significantly by approx. 80% due to an enlarged surface area due to a deeper hole design L20 compared to a smaller hole depth L10.
  • the course of the current-voltage characteristic of the components, that is to say the capacitors 100, is dependent on the different dielectric layer stacks 130. This follows a system according to which, according to one exemplary embodiment, a higher proportion of stoichiometric silicon nitride results in a larger maximum voltage at a Current flow from z. B. 10 mA leads.
  • the lower dielectric strength in layer stacks 130 with a higher proportion of low-stress silicon nitride is e.g. B. attributed to tunnel mechanisms in the dielectric. Due to the assumed higher trap density in the low-stress silicon nitride compared to the stoichiometric silicon nitride, these charge transport mechanisms dominate e.g. B. already from lower field strengths. The depth of detention was determined on the basis of temperature-dependent current-voltage measurements as a function of the electrical field strength. For the low-stress silicon nitride, these largely correspond to that of the stoichiometric silicon nitride according to one exemplary embodiment.
  • silicon capacitors 100 which have a dielectric layer stack 130 made of silicon dioxide, two stoichiometric silicon nitride layers and a low-stress silicon nitride layer, a maximum voltage at 10 mA of 1575 V could be achieved according to one exemplary embodiment.
  • a series resistance of the silicon capacitor is independent of the structure of the dielectric layer stack.
  • the low-stress silicon nitride z. B. gained a degree of freedom in relation to the mechanical stresses.
  • the first electrode structure 110 On the basis of the findings from a metrological documentation of the bending of the silicon semiconductor wafer, ie the first electrode structure 110, it is possible to enlarge the surface with deeper holes with the same layer composition with a hole design L30 (larger surface area than L20) and larger. This goes hand in hand with an increased capacity per area.
  • the depth of the hole can be increased further with an increased proportion of low-stress silicon nitride.
  • silicon capacitors with a high capacitance per area can be realized.
  • the dielectric strength of Components with a high proportion of low-stress silicon nitride according to one exemplary embodiment are lower.
  • capacitor 100 represents an optimization with regard to a minimal proportion of low-stress silicon nitride and thus a maximum dielectric strength.
  • FIG. 4a shows a picture of a broken edge of a silicon semiconductor wafer 110 with a perforated structure 111 ! to 111 5 after a rock etching process, which according to an exemplary embodiment of the present invention serves as the first electrode structure of the integrated capacitor.
  • the hole structure 111 ! up to 11 1 5 can be realized, for example, with an alternating dry etching process such as an ASE process (advanced silicon etching process, reactive ion depth etching). This creates such. B. in Fig. 4a recesses 11 1 ! to 111 5 .
  • the recesses 111 to 111 5 can have a cylindrical shape with a spherical rounding at the end in the semiconductor substrate 110. Since it is a schematic cross section through the semiconductor substrate 110 in FIG. 4a, the recesses 111 ! to 11 5 shown as rectangular recesses with rounded corners.
  • FIG. 4b shows a picture on the scanning electron microscope of a cross section of an integrated capacitor 100 according to an exemplary embodiment.
  • a first electrode structure 110, a second electrode structure 120 and an interposed dielectric layer structure 130 thus become clear in FIG. 4b.
  • a front side contact 122 is arranged on the second electrode structure 120.
  • the trench structure of the semiconductor substrate 110 can have a large number of recesses, which can be identified in FIG. 4b, inter alia, by means of the depressions 111 to 111 n in the front-side contact 122, where n is an integer positive number.
  • the recesses that define the Define ben structure of the semiconductor substrate 110 to circular holes.
  • the semiconductor substrate has a hexagonal arrangement of circular holes, which in 1111 with reference to the wells to 111 n on the front side contact 122 is indicated. This type of hole arrangement provides z. B. a very large increase in the capacitance value of the integrated capacitor 100.
  • FIG. 5a shows a schematic top view of a hexagonal hole structure as for the integrated capacitor 100 according to FIG. 4b.
  • 5b shows a cross section through a hole in the trench structure of the integrated capacitor along a cutting edge QQ in FIG. 5a.
  • 5a and 5b serve to define parameters for calculating a surface enlargement of the integrated capacitor through the hexagonal hole structure.
  • the determination z For example, the assumption has been made that the layer deposition of the dielectric materials of the dielectric layer structure 130 over the hole 111 1 to 1 11 7 is uniform.
  • the dielectric layer structure 130 is averaged over a thickness d 138. 5a and 5b, a distance a between the holes 111 is based on this ! to 111 7 , a diameter D of the holes 11 1 ! to 111 7 and a depth h of the holes 1 11 ⁇ to 1 11 7 .
  • a capacitance C LoC h structure in an equilateral triangle 102 is composed of a capacitance of half a cylinder C Ha ibzyiinder added with a capacitance of a planar surface between the holes - C Ha ib Vietnamese and a capacity of a soil in the hole C Bo den together.
  • the enlargement factor K of the surface applies
  • the structural parameters of the hole geometry can be predetermined.
  • the distance a between the holes can be in a range from 1 pm to 5 pm, 2 pm to 3 pm or 2.4 pm to 2.8 pm.
  • the diameter D of the holes can be in a range between 3 pm and 10 pm, 4.5 pm to 6.5 pm or between 5 pm and 6 pm.
  • the depth h of the holes can be in a range from 5 pm to 50 pm, 10 pm to 40 pm or 10 pm to 35 pm.
  • a first hole design L10 with a distance a of 2.75 mih, a diameter D of 5.35 miti and a depth h of 12.3 miti.
  • a hole design L20 with a distance a of 2.48 mm, a diameter D of 5.59 mm and a depth h of 22.5 mm can also be implemented.
  • a hole design L30 with a depth of approximately 30 mm can be implemented.
  • 5c shows an equivalent circuit diagram according to an exemplary embodiment of an integrated capacitor 100 with partial capacitances of different layers and structures of a dielectric layer structure 130 and the individual resistors.
  • the measured capacitance value is composed of individual capacitances from a parallel connection along the dielectric layer boundaries and a series connection according to the layer structure.
  • B. neglected the influences of a resistive voltage divider.
  • the dielectric layer structure 130 shown in FIG. 5c can have the same features and properties as the dielectric layer structure 130 from FIG. 2a or FIG. 2b.
  • the integrated capacitor 100 in FIG. 5c has an SiO 2 layer 132, a first silicon nitride layer 133i, a second silicon nitride layer 133 2 and a third silicon nitride layer 133 a .
  • the integrated capacitor 100 from FIG. 5c has a first electrode structure 110, a second electrode structure 120, a rear-side contact 112 and a front-side contact 122.
  • the bending of a silicon semiconductor wafer which serves as the first electrode structure of a large number of exemplary embodiments of the integrated capacitor 100, is a measurable variable which allows a statement to be made about the degree of internal stress in the dielectric layer structure 130. It is e.g. For example, a distinction is drawn between tensile stress, which causes a concave deflection or a positive radius of curvature, and compressive stress, which respectively produces a convex deflection or a negative radius of curvature.
  • the bending of the silicon semiconductor wafer is measured both parallel and orthogonal to the flattening at the edge of the silicon semiconductor wafer. Their bends behave congruently, which is why, for better clarity, only the maximum bends of the parallel measurement of the silicon semiconductor wafers are documented in FIG. 6a.
  • FIG. 6a shows a diagram that shows the bending 114 of the silicon semiconductor wafers of different hole geometries during the deposition of the individual dielectric layers.
  • capacitors according to the invention with a trench structure, for. B. as in exemplary embodiments according to FIGS. 3 to 5c.
  • the table from FIG. 6b shows the layer structure of the respective dielectric layer structure 130-] to 130 7 examined in FIG. 6a.
  • the differences between the hole designs L10, L20 and L30 have already been discussed above in connection with FIGS. 5a and 5b.
  • bends in a range from 0 pm to 200 pm are shown in FIG.
  • FIG. 6a (the axis of the bend 114 being subdivided into steps of 50 pm, for example).
  • FIG. 6a only shows the bending of special exemplary embodiments and it is clear that with alternative dielectric layer structures, bending in other areas can also be realized. It should be clarified that the capacitor described here is not limited to the parameters shown in FIGS. 6a and 6b.
  • the disc bending is a limit for those process steps at which the disc must be “attached” to the chuck with a vacuum (e.g. polyimide) or a robot transports the discs.
  • a vacuum e.g. polyimide
  • the capacitor according to the invention represents a concept for silicon capacitors with a dielectric strength of 1200 V.
  • the silicon semiconductor wafers with the dielectric layer stack with the structure (cf. 130 4 (E) in FIG. 6 a and FIG. 6 b) 330 nm Silicon dioxide, 500 nm low-stress silicon nitride and 1000 nm stoichiometric silicon nitride are strongly delaminated after the deposition of the second stoichiometric silicon nitride and therefore could not be processed further.
  • the silicon semiconductor wafer with the dielectric reference layer stack with the structure breaks 330 nm silicon dioxide and 1500 nm stoichiometric silicon nitride, which is due to the high intrinsic voltage, which is mainly found in stoichiometric silicon nitride.
  • an optimized combination of Si0 2 layer, Si 3 N 4 layer and Si x N y layer, as in the dielectric layer structure according to 130 2 (H, flat), 130 3 (C, flat), 130 5 (C ), 130 e (C, deep) and 130 7 (H, deep) for the integrated capacitor advantageous in terms of reducing delamination and ease of manufacture of the integrated capacitor.
  • a capacitance-voltage characteristic (C (U) characteristic) of the capacitor according to the invention is shown in FIG.
  • the capacitance-voltage characteristic curve of an MIS capacitor has a characteristic profile due to the voltage dependence of the width of the space charge zone in the substrate.
  • a DC voltage 200 from -40 V to +40 V is applied (the axis of the DC voltage 200 being divided, for example, in steps of 10 V), which is an AC voltage with an amplitude of e.g. B. 10 mV and 100 kHz is superimposed.
  • the capacitive and the resistive part of the impedance is determined from the amplitude and phase of the current flow.
  • the forward characteristic and the reverse characteristic are recorded when the voltage ramp is reversed from +40 V to -40 V.
  • capacities 210 are shown in FIG.
  • FIG. 7 shows only the C (U) characteristic of special exemplary embodiments and it is clear that with alternative dielectric layer structures, C (U) characteristics can also be realized in other areas. It should be clarified that the capacitor described here is not limited to the parameters shown in FIGS. 7 and 8b.
  • FIG. 7 shows the C (U) characteristics of three components from the center of a silicon semiconductor wafer with hole design L10 and from a component from the center of a silicon semiconductor wafer with hole design L20.
  • the p-MIS capacitors are operated according to an embodiment in accumulation.
  • the characteristic saturates in accumulation to a capacitance value (see Fig. 7). However, this saturation does not occur with all the capacitors examined.
  • the silicon semiconductor wafers with the dielectric layer combinations with a stoichiometric silicon nitride layer as a second or third silicon nitride deposition increases the value of the capacitance z. B. continues with decreasing voltage, so that the capacitance value in accumulation cannot be determined directly with this measurement setup.
  • the components, e.g. B. 130 5 (C), on the silicon wafer with hole design L20 have higher capacities than the components, for. B. 130 2 (H, flat), 130 3 (C, flat) and 130 s (I, flat), on the silicon semiconductor wafers with hole design L10.
  • the cause is the larger surface due to the deeper holes of the hole design L20 compared to the surface of the hole design L10.
  • An overall permittivity of a dielectric stack is greater with a higher proportion of low-stress silicon nitride. This also increases the capacity.
  • a larger thickness of the dielectric stack is associated with a smaller capacitance value. Accordingly, the capacitance value of the silicon semiconductor wafer 130 2 (H, flat) (see FIG. 6b and FIG. 7) is increased due to a pronounced discrepancy between a small thickness and a larger overall permittivity.
  • a current-voltage characteristic of the capacitors according to the invention is suitable for determining the dielectric strength and for identifying different charge transport mechanisms in the capacitor.
  • the dielectric strength of a capacitor is e.g. B. depending on the thickness of the dielectric (ie the dielectric layer structure) and the electric field strength.
  • An irreversible breakdown of the dielectric takes place when a critical field strength E crit is exceeded at a breakdown voltage U B D.
  • reached V , ma x is determined at a current flow of 10 mA. No dielectric breakdown can be determined in any of the measured layer stacks up to the maximum voltage reached. The breakdown voltage is therefore greater than the maximum voltage reached, so that the producibility of capacitors with a dielectric strength of 1200 V can be successfully confirmed.
  • FIG. 8a shows measured output characteristics of Si capacitors with a dielectric made of silicon dioxide and silicon-rich nitride (130 8 (I, flat)) and a combination of silicon-rich and stoichiometric nitride (130 2 (H, flat), 130 3 (C, flat), 130 5 (C)) of the same or similar total thickness.
  • 8a shows the current measured on the component via the applied voltage.
  • the current is z. B. logarithmic in a range from 10 8 A to 10 2 A and the voltage is z. B. in a range of 0 V to 1600 V in steps of 200 V.
  • FIG. 8a only shows the current over the voltage of special exemplary embodiments and it is clear that with alternative dielectric layer structures, currents in other areas (for example in other current and / or voltage areas) can also be realized. It should be clarified that the capacitor described here is not limited to the parameters shown in FIGS. 8a and 8b.
  • a preferred embodiment of the present invention is the capacitor with the dielectric layer structure according to 130 3 (C, flat).
  • FIG. 8b shows the different layer stacks analyzed in FIG. 8a with the maximum voltage reached and the total layer thickness of the dielectric.
  • the contact between the stoichiometric silicon nitride and the underlying silicon dioxide turns out to be advantageous in relation to a higher maximum voltage achieved.
  • the contact between low-stress silicon nitride and the front electrode which has a negative effect on the current-voltage characteristic due to the higher defect density in the low-stress silicon nitride compared to the stoichiometric silicon nitride (130 2 (H, flat), 130 3 (C, flat)) could not be confirmed on the basis of measurements.
  • a silicon capacitor such as, for example, 130 5 (C)
  • the trench structure of which has a hole depth of approximately 20 pm and which has a dielectric layer stack composed of 330 nm silicon dioxide, 500 nm stoichiometric silicon nitride, 500 nm low-stress silicon nitride and 500 nm stoichiometric silicon nitride, an optimized concept in terms of capacitance and dielectric strength.
  • This achieves a capacitance of 133 pF / mm 2 and a dielectric strength of 1450 V per area.
  • 9 schematically shows individual successive process steps of a method 300 for producing the silicon capacitors according to the invention in accordance with an exemplary embodiment of the present invention. Particular attention should be paid to the fact that only the processing of the relevant front side of the silicon semiconductor wafer is shown schematically in FIG. 9 and that deposits on the rear side and their etching back processes are not included.
  • silicon substrate 1 10 which represents a first electrode structure, is structured with holes 111 to 1 11 3 in order to implement a trench capacitor 100 according to an exemplary embodiment.
  • the hole structure is transferred to the surface by means of a lithography 310 and is then etched 320 into the depth of the substrate.
  • This is followed by the different processes for the deposition 330 of the individual layers 132 and 133 ! to 133 3 of the dielectric 130, ie the dielectric layer structure, and to the deposition 340 of the electrode 120, ie the second electrode structure.
  • the method optionally includes producing 350 a front side contact 122 and a rear side contact 1 12.
  • the electrode 120 consisting of e.g. B. polycrystalline silicon, and the front contact 122 made of z. B. aluminum define dimensions of the component.
  • polyimide is optionally applied to the edge of the components.
  • the capacitor 100 according to the invention is based on a boron p-doped silicon semiconductor wafer (i.e. silicon substrate 110), which e.g. B. measures a diameter of 150 mm, a thickness of 675 pm and a specific sheet resistance of 9 ⁇ 0.3 ohm * cm.
  • a lithography 310 z For example, a hexagonal hole structure, as described in FIGS. 4b and 5a, is produced on the surface of the silicon 110.
  • the etching 320 of the holes 11 ⁇ to 111 3 takes place, for example, with an ASE process (advanced silicon etching process), which is an alternating dry etching process.
  • ASE process advanced silicon etching process
  • the holes 1 1 1 ! to 1 11 3 alternated between an ion etching step and a passivation step according to an embodiment.
  • passivation between the individual not completely anisotropic etching steps z.
  • the dielectric 130 consists of a silicon dioxide layer 132 and three subsequent silicon nitride layers 133i to 133 3 with different properties. These are named after the separation sequence Siliciumnitridl 133 ⁇ Siliciumnitrid2 133 2 and SiliconnitridS 133 3 .
  • the Si0 2 layer 132 z. B. by means of thermal oxidation, which is based on a natural reaction of silicon (Si) with oxygen (0 2 ) to silicon dioxide (Si0 2 ), at z. B. 1050 ° C deposited 330 on the silicon substrate.
  • a silicon nitride layer 133i to 133 3 is e.g. B. generated by a chemical reaction of dichlorosilane (SiCl 2 H 2 ) with ammonia (NH 3 ).
  • the deposition 330 of the different silicon nitride layers 133-i to 133 3 takes place e.g. B. by means of a chemical low pressure vapor deposition (LPCVD) at a lower pressure (about 17 Pa - 27 Pa) than the atmospheric pressure and a temperature between 700 ° C and 800 ° C instead.
  • LPCVD chemical low pressure vapor deposition
  • the chemical reaction equation for the deposition 330 of stoichiometric silicon nitride is 3 SiCI 2 H 2 + 4NH 3 - * ⁇ Si 3 N 4 + 6 HCl + 6H 2 . This produces hydrogen chloride (HCl) and hydrogen (H 2 ) as by-products of the reaction.
  • the deposition 330 of low-stress silicon nitride changes the ratio of the reaction gases dichlorosilane and ammonia. The higher the proportion of dichlorosilane in relation to ammonia, the higher the proportion of silicon in the resulting silicon nitride. This means that no silicon nitride with the ratio of silicon to nitride of three to four is deposited as in the stoichiometric case, but rather a silicon-rich silicon nitride or non-stoichiometric silicon nitride 330, which is also referred to as low-stress silicon nitride Si x N y .
  • an SiO 2 layer is thus first deposited on the silicon substrate and then combinations of layers 133i to 133 3 comprising at least one Si 3 N 4 layer and at least one Si x N y Layer.
  • the front electrode 120 ie as the second electrode structure, z. B. polycrystalline silicon by means of an LPCVD process with monosilane (SiH 4 ) SiH 4 -> Si + 2H 2 grew 340.
  • the necessary electrode 120 is formed to achieve an increased capacitance value.
  • the polysilicon is doped with phosphorus and argon during the deposition by an additional gas supply of monophosphane (PH 3 ) and argon (Ar).
  • the second electrode structure 120 is followed by a further layer for forming the front-side contact 122 with z. B. aluminum.
  • This additional layer is e.g. B. deposited with a PVD process, the evaporation.
  • Aluminum has a low resistance and forms a reliable contact between the individual components.
  • the dimension of the component is optionally transferred to the silicon semiconductor wafer by means of lithography and the layers of polysilicon and aluminum are removed between the resulting components using a dry etching process.
  • solderable layer stack 1 12 made of chromium, nickel and silver.
  • an integrated capacitor has a first electrode structure, a second electrode structure and an intermediate dielectric layer structure, the dielectric layer structure being a layer combination with an Si0 2 layer, an Si 3 N layer and an Si x N y layer and wherein the Si x N y layer comprises non-stoichiometric silicon nitride material with an increased silicon content.
  • the first electrode structure has a semiconductor substrate provided with a trench structure.
  • the first electrode structure forms a rear side electrode, which is arranged on a rear side contact; and the second electrode structure forms a front side electrode, which is arranged on a front side contact.
  • a ratio of silicon and nitrogen of the Si x N y layer is between 0.8 and 1.
  • the dielectric layer structure has a higher proportion of an Si 3 N 4 material than material deviating therefrom.
  • a thickness of the Si 3 N 4 layer to the thickness of the Si x N y layer is formed in a ratio n to one, where n is between 1.5 and 2.5.
  • the Si x N y layer is arranged separately from or not directly on the Si0 2 layer.
  • a thickness of the Si x N y layer corresponds to at most 33% of a total thickness of all Si x N y layers and Si 3 N layers.
  • a thickness of the Si x N y layer corresponds to at most 50% of a total thickness of all Si 3 N 4 layers.
  • the dielectric layer structure of the integrated capacitor has an effective oxide thickness of at least 1200 nm and a dielectric strength of at least 900 V.
  • a method for producing an integrated capacitor comprises producing a dielectric layer structure in a trench structure of a semiconductor substrate, the dielectric layer structure having a plurality or a combination of adjoining dielectric layers, at least one of the dielectric layers having SiO 2 material, at least one one of the dielectric layers has Si 3 N 4 material and at least one of the dielectric layers has Si x N y material, the Si x N y material having non-stoichiometric silicon nitride with an increased silicon content.
  • the dielectric layer structure has a plurality or a combination of an Si0 2 layer, an Si 3 N 4 layer and an Si x N y layer.
  • a ratio of silicon and nitrogen in the SixNy layer is between 0.8 and 1.
  • the dielectric layer structure has a higher proportion of the Si 3 N 4 material than material deviating therefrom.
  • a thickness of the Si 3 N 4 layer is formed in relation to a thickness of the SixNy layer in a ratio n to one, where n is between 1.5 and 2.5.
  • the Si x N y layer is not arranged directly on the Si0 2 layer.
  • One exemplary embodiment relates to a method according to one of the exemplary embodiments described above.
  • Another exemplary embodiment relates to a device according to one of the exemplary embodiments described above.
  • Another exemplary embodiment relates to a production method according to one of the exemplary embodiments described above.
  • aspects have been described in connection with a device, it goes without saying that these aspects also represent a description of the corresponding method, so that a block or a component of a device can also be understood as a corresponding method step or as a feature of a method step. Analogously, aspects that have been described in connection with or as a method step also represent a description of a corresponding block or details or features of a corresponding device.

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Abstract

Condensateur intégré comprenant une première structure d'électrode, une deuxième structure d'électrode et une structure de couches de diélectrique disposée entre celles-ci. La structure de couches de diélectrique comprend une combinaison de couches comprenant une couche de Si02, une couche de Si3N4 et une couche de SixNy. La couche de SixNy comprend un matériau de nitrure de silicium non stoechiométrique avec une teneur en silicium accrue.
EP19786544.7A 2018-10-09 2019-10-08 Condensateur intégré et procédé pour la fabrication d'un condensateur intégré Pending EP3864713A2 (fr)

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DE102014223904A1 (de) * 2014-11-24 2016-05-25 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Kondensator und Verfahren zum Herstellen desselben
WO2017145515A1 (fr) * 2016-02-22 2017-08-31 株式会社村田製作所 Condensateur à semi-conducteur et module d'alimentation électrique

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JP2022504537A (ja) 2022-01-13
JP7208373B2 (ja) 2023-01-18
US20210257502A1 (en) 2021-08-19

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