EP1116255A1 - Composants d'emission de champ d'electrons a grille isolee et leurs procedes de fabrication - Google Patents

Composants d'emission de champ d'electrons a grille isolee et leurs procedes de fabrication

Info

Publication number
EP1116255A1
EP1116255A1 EP00948927A EP00948927A EP1116255A1 EP 1116255 A1 EP1116255 A1 EP 1116255A1 EP 00948927 A EP00948927 A EP 00948927A EP 00948927 A EP00948927 A EP 00948927A EP 1116255 A1 EP1116255 A1 EP 1116255A1
Authority
EP
European Patent Office
Prior art keywords
emitter
anode
gate electrode
insulating layer
gate
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.)
Withdrawn
Application number
EP00948927A
Other languages
German (de)
English (en)
Inventor
Michael D. Potter
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.)
Advanced Vision Technologies Inc
Original Assignee
Advanced Vision Technologies Inc
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 Advanced Vision Technologies Inc filed Critical Advanced Vision Technologies Inc
Publication of EP1116255A1 publication Critical patent/EP1116255A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
    • H01J1/02—Main electrodes
    • H01J1/30—Cold cathodes, e.g. field-emissive cathode
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J21/00—Vacuum tubes
    • H01J21/02—Tubes with a single discharge path
    • H01J21/06—Tubes with a single discharge path having electrostatic control means only
    • H01J21/10—Tubes with a single discharge path having electrostatic control means only with one or more immovable internal control electrodes, e.g. triode, pentode, octode
    • H01J21/105—Tubes with a single discharge path having electrostatic control means only with one or more immovable internal control electrodes, e.g. triode, pentode, octode with microengineered cathode and control electrodes, e.g. Spindt-type
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
    • H01J9/02—Manufacture of electrodes or electrode systems
    • H01J9/022—Manufacture of electrodes or electrode systems of cold cathodes
    • H01J9/025—Manufacture of electrodes or electrode systems of cold cathodes of field emission cathodes

Definitions

  • This invention relates generally to microelectronic devices and their fabrication processes, and more particularly to insulated-gate field emission microelectronic devices having a gate electrode disposed outside a chamber containing an emitter and an anode.
  • gate and "gate electrode” are used interchangeably throughout the present specification and the appended claims to mean any electrode other than an emitter or anode of an electron field-emission device, whether the gate is to be used as a control electrode or extraction electrode or performs some other function.
  • the microelectronic device may have more than one gate, and physically distinct gates may be electrically independent or may have related electrical potentials applied.
  • lateral refers generally to a direction parallel to a substrate on which an electronic device is formed.
  • a “lateral field-emission device” refers to a field-emission device formed on a substrate and formed with a structure such that an anode is spaced apart from a field emitter along at least a direction parallel to the substrate.
  • lateral emitter refers to a field emitter made substantially parallel to the substrate of a lateral device, whereby emission of electrons toward the anode occurs generally parallel to the substrate. Examples of such lateral emitters formed of thin films are known in the related art.
  • substrate refers to any of the following: a simple base substrate consisting of a single material, or a composite substrate consisting of a base substrate on which one or more layers of a different material have been added, or the top layer of such a composite substrate.
  • field-emission device structures including diodes, triodes, and tetrodes, have been developed for use in electronic circuits. Some of the field-emission devices have been adapted specifically for use in displays. In such displays, each pixel cell uses one or more field-emission devices. Field-emission displays are considered an attractive alternative and replacement for flat-panel liquid crystal displays, because of their lower manufacturing cost and lower complexity, lower power consumption, higher brightness, and improved range of viewing angles. There is a continuing need for improved microelectronic device structures and fabrication processes, especially for flat panel displays.
  • microelectronic field-emission devices in the related art have had gate electrodes exposed to the same vacuum or gas-filled environment as the emitter, thus exposing the gate electrode to direct current of electrons from the field-emission cathode and allowing secondary emission to occur from the surface of the gate electrode.
  • a lateral-emitter field emission device has a gate that is separated by an insulating layer from a vacuum- or gas-filled environment containing other elements of the device.
  • the gate may be disposed external to a microchamber.
  • the insulating layer is disposed such that there is no vacuum- or gas-filled path to the gate for electrons that are emitted from a lateral emitter.
  • the insulating layer disposed between the emitter and the gate preferably comprises a material having a dielectric constant greater than one.
  • the insulating layer also preferably has a low secondary electron yield over the device's operative range of electron energies.
  • the insulating layer is preferably transparent. Emitted electrons are confined to the microchamber containing their emitter.
  • the gate current component of the emitter current consists of displacement current only, and direct electron current from the emitter to the gate is prevented.
  • An array of the devices comprises an array of microchambers, so that electron current from each emitter can reach only the anode in the same microchamber, even for diode devices lacking a gate electrode.
  • a fabrication process is specially adapted for fabricating the device and arrays of such devices, including formation in situ of a vacuum microchamber.
  • FIGS. 1 - 13 show a series of side-elevation cross-sectional views illustrating overall fabrication of a confined-electron device made in accordance with the invention.
  • FIG. 14 shows a flow chart illustrating an overall fabrication process performed in accordance with the invention.
  • FIGS. 15 - 27 show a series of side-elevation, cross-sectional views illustrating fabrication of an insulated-gate electron field emission device made in accordance with the invention. Modes for Carrying Out the Invention
  • CMOS complementary metal-oxide-semiconductor
  • PMOS complementary metal-oxide-semiconductor
  • Bipolar Bipolar-CMOS
  • the new device may also be used for a display element or as a display system. It may incorporate integrated luminescent materials or may be used in conjunction with luminescent materials on a separate subassembly. It may also have integrated display driver circuitry.
  • FIGS. 1 - 11 show side elevation, cross-sectional views illustrating various stages in an overall process of making a device in accordance with the invention.
  • FIG. 14 is a flow chart illustrating a first overall process for making a device in accordance with the invention.
  • a conducting substrate 15 is used, a first insulating layer is deposited on the conducting substrate 15 to form an insulating substrate 20. If an insulating substrate 20 is used, as shown in FIG. 1, this step is omitted.
  • a conducting gate material 30 is deposited and patterned onto the first insulating layer (FIG. 1).
  • a second insulating layer 40 is deposited over the gate layer 30 (FIG. 2).
  • a conducting emitter layer 50 is deposited and patterned onto the second insulating layer 40 (FIG. 3).
  • a third insulating layer 60 is deposited over the emitter layer 50 (FIG. 4).
  • a trench 70 is formed (FIG. 5) which removes a portion of the third insulating layer 60 down to the emitter layer 50.
  • the emitter material in the trench-defined area is removed (FIG. 6), leaving at least an emitting edge 80 on emitter layer 50.
  • a portion of the second insulating layer 40 may be removed. However, a portion of the second insulating layer 40 remains which eliminates any vacuum path and prevents DC current between the emitter 50 and the gate 30.
  • Conventional contact holes, inter-layer studs, etc. are provided for by conventional semiconductor fabrication means.
  • the structure made by this process may form a subassembly for various systems such as flat panel displays.
  • a separate faceplate 100 coated with luminescent material is placed above the trench area (FIG. 7), forming a chamber 110.
  • a focusing grid (not shown) may be inserted between the emitter 50 (i.e., emitter edge 80) and the faceplate 100.
  • the faceplate may be replaced with a conducting material to act as an anode. Spacer columns 90 and/or sealing may also be used.
  • FIG. 6 The structure described above (FIGS. 1 -6) may be a part of an integrated device.
  • This integrated device may be an active triode or a display element.
  • a sacrificial material 120 is deposited and patterned (FIG. 8), which completely fills at least the trench- defined area 70.
  • a conducting anode 130 is deposited onto the third insulating layer 60 and the sacrificial layer 120 combination (FIG. 9). This conducting anode 130 may be patterned if desired.
  • An access hole 140 is made through the anode-conducting layer 130 by means of standard semiconductor fabrication techniques (FIG. 10).
  • the sacrificial material 120 is removed through the access hole 140, leaving empty chamber 160.
  • a sealant material 150, 155 is deposited in a vacuum system (FIG. 11).
  • the vacuum level is defined to be sufficient for the operation of the triode device.
  • the sealant material 150, 155 may be re-flowed in situ if required.
  • the sealant material 150, 155 may be patterned if required.
  • a sacrificial material 120 is deposited and patterned, which completely fills at least the trench- defined area 70. (See FIG. 8)
  • a luminescent anode material 135 is deposited onto the third insulating layer 60 and the sacrificial layer 120 combination. This luminescent anode material layer 135 may be patterned if desired. A fourth transparent insulating layer (not shown) may be deposited over the luminescent material layer 135 if needed. An access hole 140 is made through the anode material layer 135 by means of standard semiconductor fabrication techniques. The sacrificial material 120 is removed through the access hole 140. (See FIG. 10.)
  • a sealant material 150, 155 is deposited in a vacuum system (FIG. 13).
  • the vacuum level provided is to be sufficient for the operation of the display element.
  • the sealant material 150, 155 may be re-flowed in situ if required.
  • the sealant material 150, 155 may be patterned to remove it over the display element light emitting area. This layer 150, 155 may be left intact if it is a transparent material.
  • S9 Enclose chamber (S9a) and perform steps Sll, S12, S13, S14, and S15
  • FIG. 14 is a flow chart illustrating this overall fabrication process, with the various process steps designated by reference numerals SI, S2, ... , S17. For each of these steps, the act performed is listed in Table I (previous page).
  • Part II Described in the following description is a new insulated-gate electron field emission device.
  • the structure has no vacuum path between the emitter and the gate of the device.
  • This new structure eliminates any possible DC gate current, thereby making the device behave as a purely ballistic electron field effect transistor. It may have integrated circuitry made of similar device structures, solid state device structures such as silicon or III-V materials including CMOS, NMOS, PMOS, Bipolar, Bi-CMOS, etc.
  • the new device is particularly useful for high frequency applications including wireless communication systems.
  • Part II The first case described in this section (Part II) is for a common gate structure for process simplification.
  • the preferred embodiment is the second case described in this section (Part II).
  • a conducting substrate 15 is used, and a first insulating layer 25 is deposited on the conducting substrate 15, thus forming an insulating substrate.
  • a second insulating layer 40 is deposited on the first insulating layer.
  • the first insulating layer 25 and the second insulating layer 40 are distinguished from each other by having different etch characteristics for an etchant used later in the process.
  • a conducting emitter material layer 50 is deposited on the second insulating layer and patterned (FIG. 16).
  • a third insulating layer 60 (also shown in FIG. 16) is deposited on the emitter layer 50.
  • the third insulating layer 60 is patterned (FIG. 17) by etching to form openings 65 and 75 for the emitter contact stud and the anode member respectively. This etching process stops on the emitter layer 50 and on the first insulator layer 25, as shown in FIG. 17.
  • the openings 65 and 75 are filled (FIG. 18) with a conducting material to form respectively an emitter contact stud 85 and an anode 95) and planarized by using conventional chemical mechanical polishing (CMP).
  • CMP chemical mechanical polishing
  • a trench 70 is etched (FIG. 19) which exposes at least a portion of the emitter layer 50, leaving an emitting edge 80 on emitter layer 50, and exposes at least a portion of anode 95. The etch will stop on the first insulating layer 25, as shown in FIG. 19.
  • a sacrificial layer 120 is deposited on the third insulating layer 60, the emitter contact stud 85, and the anode 95 (FIG. 20).
  • the sacrificial layer is patterned as shown in FIG. 20.
  • a fourth insulating layer 165 is deposited (FIG. 21) on the third insulating layer 60 and the sacrificial layer 120.
  • Access holes 170 and 180 are patterned and etched through the fourth insulating layer 165, and the sacrificial material 120 is removed (FIG. 22) through access holes 170 and 180, leaving opening 70 empty.
  • the access holes 170 and 180 are disposed so that at least a portion of each access hole is aligned with an underlying element, one (170) aligned over the emitter contact stud 85 and the other (180) aligned over the anode 95, as shown in FIG. 22.
  • a material 190 such as a metal, is deposited on the fourth insulator 165 in a vacuum (FIG. 23).
  • the material 190 is re-flowed in situ to seal the access holes 170 and 180.
  • the sealing material 190 is patterned to leave material substantially over access holes 170 and 180, thus sealing them.
  • the chamber body is thus fabricated in situ as a vacuum chamber 160.
  • the sealing plugs formed by material 190 may further provide conductive electrical contacts to the emitter and the anode (FIG. 23).
  • a structure for a non-common gate is disclosed below that significantly reduces the gate to emitter and gate to anode capacitance.
  • the reduced capacitance maximizes the switching speed and overall performance of the device.
  • a conducting substrate 15 is used, a first insulator 25 is deposited to isolate the device. If an insulating substrate 20 is used, an additional first insulating layer 25 may not be required.
  • the process for an insulating substrate 20 case is described below.
  • a gate trench 200 is patterned and etched into the insulating substrate (FIG. 24).
  • a first conducting gate layer 210 is deposited on the insulating substrate and planarized to a level that fills the trenches (FIG. 25) to form a gate electrode 30. The process from this point is the same as the preceding description from the point of depositing the first insulating layer through depositing the third insulating layer (FIGS. 15 - 16).
  • a third opening (not shown) is provided that will act as the gate conducting contact for contacting gate electrode 30.
  • An etch that etches to the gate conducting layer 210 is performed to provide for the gate contact. (The gate contact, being outside of the cross-section plane of FIGS. 26 and 27, is not shown).
  • the anode 95 is at least partially composed of a luminescent material.
  • a bi-directional device can be fabricated by replacing the anode with a mirror image of the emitter member 50 and gate member 30, as shown in FIG. 27.
  • a gate 30 can be shared between two emitters 50, or a separate gate 30 can control each emitter 50.
  • Conventional contact holes, inter-layer studs, etc. are provided for by conventional semiconductor fabrication means.
  • the invention is useful in fabrication of field emission devices and is especially useful for field emission displays that consist of an array of field emission devices, since each device in the array may have a separate microchamber containing an emitter and a cathodoluminescent anode responsive only to electrons from its own emitter. If made with a gate electrode separated from each microchamber by an insulating layer, each microelectronic device has improved performance.
  • the preferred fabrication process is specially adapted for simultaneous fabrication of many devices in such an array.
  • the invention eliminates or greatly reduces direct current flowing from the emitter to the gate of an electron field-emission microelectronic device.
  • the invention can also reduce undesirable secondary electron emission without requiring introduction of an additional electrode for secondary-electron-emission suppression. Secondary electron emission from a gate electrode could otherwise adversely affect control of anode current by the gate electrode.
  • crosstalk between pixels is eliminated.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
  • Cold Cathode And The Manufacture (AREA)

Abstract

Composant d'émission de champ à émetteur latéral possédant une grille (30) séparée par une couche isolante (40) d'un environnement sous vide ou rempli de gaz contenant d'autres éléments du composant. Par exemple, la grille peut être placée à l'extérieur d'une microchambre (110). Cette couche isolante est placée de sorte qu'il n'existe aucun trajet sous vide ou rempli de gaz vers la grille pour les électrons émis par l'émetteur latéral. La couche isolante placée entre l'émetteur et la grille est composée, de préférence, d'un matériau possédant une constante diélectrique supérieure à un. Cette couche isolante possède également, de préférence, une production secondaire basse d'électrons par rapport à la plage opérationnelle d'énergies d'électrons du composant. Pour des raisons de visibilité, la couche isolante est, de préférence, transparente. Les électrons émis sont confinés à la microchambre contenant leur émetteur. De ce fait, la composante de courant de grille du courant de l'émetteur ne consiste qu'en un courant de déplacement, ce qui empêche un courant continu d'électrons depuis l'émetteur vers la grille. Un groupement de ces composants comprend un groupement de microchambres, de sorte que le courant d'électrons provenant de chaque émetteur ne peut atteindre que l'anode de la même microchambre, même pour des composants à diodes manquant d'une électrode de grille. Un procédé de fabrication est particulièrement adapté pour fabriquer ce composant et des groupements de ces composants, y compris la constitution in situ d'une microchambre sous vide.
EP00948927A 1999-07-26 2000-07-24 Composants d'emission de champ d'electrons a grille isolee et leurs procedes de fabrication Withdrawn EP1116255A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US14557099P 1999-07-26 1999-07-26
US145570P 1999-07-26
PCT/US2000/020144 WO2001008192A1 (fr) 1999-07-26 2000-07-24 Composants d'emission de champ d'electrons a grille isolee et leurs procedes de fabrication

Publications (1)

Publication Number Publication Date
EP1116255A1 true EP1116255A1 (fr) 2001-07-18

Family

ID=22513686

Family Applications (1)

Application Number Title Priority Date Filing Date
EP00948927A Withdrawn EP1116255A1 (fr) 1999-07-26 2000-07-24 Composants d'emission de champ d'electrons a grille isolee et leurs procedes de fabrication

Country Status (6)

Country Link
EP (1) EP1116255A1 (fr)
JP (1) JP2003505843A (fr)
KR (1) KR20010075311A (fr)
CN (1) CN1319246A (fr)
CA (1) CA2355660A1 (fr)
WO (1) WO2001008192A1 (fr)

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Publication number Priority date Publication date Assignee Title
KR20060088865A (ko) * 2006-07-13 2006-08-07 정효수 광방출 소자, 그 제조방법 및 광방출 소자를 이용한 노광장치
EP2915161B1 (fr) 2012-11-05 2020-08-19 University of Florida Research Foundation, Inc. Compensation de luminosité dans un affichage

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Also Published As

Publication number Publication date
CA2355660A1 (fr) 2001-02-01
CN1319246A (zh) 2001-10-24
JP2003505843A (ja) 2003-02-12
WO2001008192A1 (fr) 2001-02-01
KR20010075311A (ko) 2001-08-09

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