JPS5882575A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE:To reduce floating capacity of the device by a method wherein a III-V group compound semiconductor made to have the semiinsulating property by adding impurities to form a deep level is used for a substrate, and out of a metamorphosed layer generated on the surface by a heat treatment, only the surface layer part is removed to be made as the substrate for a Schottky junction type FET. CONSTITUTION:The heat treatment is performed at 800 deg.C for about 5hr to the GaAs substrate 1 made to have the semiinsulating property by adding Cr to form the deep level, added Cr is made to diffuse toward the surface of the substrate 1, and the thermally metamorphosed layer 4 consisting of the low resistance surface layer part 2 scarcely containing Cr or containing scanty Cr even when Cr is contained, and the surface layer part 3 containing a large quantity of Cr and positioning on the surface thereof, is made to be generated. Then the surface layer part 3 is removed using an aqueous solution of sulfuric acid, the low resistance surface layer part 2 is left as the surface layer part 5, a source electrode 7 and a drain electrode 8 consisting of an AuGe alloy are formed thereon, an Al gate electrode 9 is provided between them, and the Schottky junction 10 is made to be generated between the electrode 9 thereof and the surface layer part 5.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor device in which required semiconductor elements are formed using a semiconductor substrate having a structure in which a low resistance semiconductor layer is formed on the surface side of a semi-insulating semiconductor substrate body, and a semiconductor device thereof. Concerning improvements in manufacturing methods.

Since the semiconductor device uses a semi-insulating semiconductor substrate as its semiconductor substrate, a plurality of semiconductor elements formed using the semiconductor substrate are separated from each other. It has the characteristics that it can be constructed as a single object, and that each semiconductor element can be constructed as a small floating container.

In order for the semiconductor device to have high performance, it is necessary to have a high electron mobility in the low-resistance semiconductor layer that can form the semiconductor substrate. It is required to have a large thickness, a small specific resistance, etc.

However, conventional semiconductor devices of this type and methods of manufacturing the same have the drawback of not being able to fully satisfy the above-mentioned requirements.

Therefore, the present invention aims to propose a novel semiconductor device of this type and a method for manufacturing the same that does not have the above-mentioned drawbacks, which will become clear from the detailed description below.

An example of a semiconductor device according to the present invention and an example of its manufacturing method are as follows:
To describe an example of the manufacturing method with reference to FIG. 1, a ■-V group compound semiconductor substrate made of GaAs which has been made semi-1#1# by using the impurity Or that forms a deep level. The main body 1 is prepared in advance (FIG. 1A).

Therefore, for the ■-■ group compound semiconductor substrate body 1,
For example, the heat treatment is performed at 800° C. for 5 hours in an atmosphere having an A3 vapor pressure of 1 atm, for example. In such a case, Or as an impurity added to the surface III of the semiconductor substrate body 1 diffuses or is transported toward the surface of the semiconductor substrate body 1, and as a result, the semiconductor as shown in FIG. Cr as an impurity on the surface side of the substrate body 1
The part 2 that contains almost no violet, or even if it does contain much less violet than before the heat treatment, and therefore exhibits low resistance, and the Or on that part 2 are heat treated. Heat-denatured NlI4 is formed which has a larger amount of NlI4 in the surface portion 3 than before. In this case, the heat-denatured layer 4 can be formed to have a thickness of α2 μm% and a surface portion 6 of α1 μm.

Next, the semiconductor substrate body 1 is heat-treated to form a heat-denatured layer 4 on its surface side, and then the heat-denatured layer 4 is etched using, for example, a sulfuric acid-based aqueous solution to form a heat-denatured layer 4 on the surface side. is removed to a sufficient thickness that at least the surface portion 3 is removed, so that at least the surface portion of the thermally denatured layer 4 of the thermal layer 4 is removed on the surface side of the semiconductor substrate body 1. The part that is thick enough for 6 to be removed is the part that remains after being removed (the part due to the part 2 mentioned above)
Thus, a semiconductor substrate 6 having a structure in which a low-resistance semiconductor layer 5 is formed on the surface side of a fiber-V group compound semi-solid base body 1 is obtained (FIG. 1C). ).

Next, in order to form a Schottky junction micro-field-effect transistor as a semiconductor element using the semiconductor substrate 6 thus obtained, a source electrode having a required pattern is formed on the low-resistance half-layer 5 of the semiconductor substrate &6. 7 and the drain electrode 8,
For example, the AuGa base metal is formed into ohmic contact with the low-resistance semiconductor layer 5 by vacuum evaporation treatment, for example, heat treatment in hydrogen gas at 460° C. for 5 minutes, etc. A gate electrode 9 is formed on the resistive semiconductor layer 5 in a region between the source electrode 7 and the drain electrode 8.
is formed to form a Schottky junction 10 with the low-resistance semiconductor layer 5, including, for example, a vacuum evaporation process of M (FIG. 1E), and then by a Mena etching process on the low-resistance semiconductor layer 5. Then, unnecessary regions of the low-resistance semiconductor layer 5 are removed, thereby obtaining the desired semiconductor device in which a Schottky junction field effect transistor M1 as a semiconductor element is formed (FIG. 1F).

An example of the configuration of the semiconductor device according to the present invention (FIG. 1F) has been described above.
) and an example of its manufacturing method have been clarified, and according to an example configuration of a semiconductor device according to the present invention, it is made semi-insulating by adding Or as an impurity to form a deep unit. Using a semiconductor substrate consisting of a semiconductor substrate 6 having a configuration in which a low resistance semiconductor layer 5 is formed on the surface side of a semi-insulating semiconductor substrate body consisting of a conductor body 1 made of a group compound compound. , has a configuration in which a semiconductor device is formed of a Schottky junction field effect transistor M1, and in this case, the semiconductor substrate (semiconductor substrate 6) is a semi-4e edge semiconductor substrate body (impurity forming a deep level). Since this is a semiconductor substrate using a GaAs group compound semiconductor substrate body 1) which has been made semi-insulating by adding cr as The semiconductor element (Schottky junction field effect transistor M1) formed by the semiconductor device can be configured as being separated from each other, and the semiconductor element can be configured as having a small stray capacitance. It is something.

However, in the case of the semiconductor device according to the present invention, the semiconductor substrate (semiconductor substrate 6) is composed of an insulating semiconductor substrate body (made of GaAs made semi-insulating by adding Or as an impurity to form a deep level). ■-V group compound semiconductor substrate body 1) contains impurities (
Ml-V made semi-insulating by Matsuka of Or)
A GaAs group compound semiconductor (GaAs), in which a low resistance semiconductor layer (low resistance semiconductor layer 5) is made semi-insulating by adding an impurity (Or) to form a deep level. Due to the heat treatment of GaAa), the heat-denatured layer (thermal-denatured layer 4) formed on the surface side of the humble-III group compound semiconductor is removed to a required thickness, so that the remaining heat-denatured layer is removed. Therefore, the low resistance semiconductor layer (low resistance semiconductor layer 5) has a significantly high electron mobility. Incidentally, in the case of the top layer according to the present invention, the electron mobility is 6500 cI at room temperature.
It has a value of i/V-1.C, which is approximately 1.2 times the value when the low-resistance semiconductor layer is formed by conventional ion implantation. Also, for this reason, the semiconductor element (Schottky junction field effect transistor M1) has a high performance. Incidentally, in the case of the overlayer according to the present invention, the mutual conductance is approximately twice as high as that when the low-resistance semiconductor layer is formed by the epitaxial growth method as compared to the case where the low-resistance semiconductor layer is formed by the conventional ion implantation method. This value is about 12 times that of the case where

According to an example of the method for manufacturing a semiconductor device according to the present invention described above, a ■-■ group compound semiconductor substrate body 1 is prepared, which is made semi-insulating by adding only impurities that form a deep level. A), by heat treatment of the stone-V & compound semiconductor substrate body 1, a thermally denatured layer 4 is formed on the surface side of the m1ll-V group compound semiconductor substrate body 1 (FIG. 1B)
, remove the surface side of the heat-modified layer 4 to a required thickness, and then apply the heat-modified layer 4 of the thermo-agricultural layer 4 to the surface of the V group compound semi-solid substrate body 1. The required bank height on the front side is the low resistance conductor i due to the part left after being removed.
@5, thus obtaining a semiconductor substrate 6 having a structure in which a low resistance semiconductor 1-5 is formed on the surface side of the ■-■ group compound semiconductor substrate body 1 (FIG. 1C), and using this semiconductor substrate 6. TeF
Since this method forms a 9T semiconductor element (Schottky junction m11L field effect transistor Ml), it has the great feature that a semiconductor element having the above-mentioned performance can be formed simply and easily. It is something.

Next, another example of the semiconductor device according to the present invention and an example of its manufacturing method will be described with reference to FIG. 2. A ■-■ group compound semiconductor substrate body 21 made of chemically modified InP is prepared in advance (FIG. 2A).

Then, the m-■ group compound semiconductor substrate body 21 is heat-treated at, for example, 800° C. for, for example, 7 hours, for example, for 1 hour.
This is done in an atmosphere having a P vapor pressure of atmospheric pressure. When it happens,
On the surface side of the semiconductor substrate body 21, F. as an impurity added thereto is diffused or transported toward the surface of the semiconductor substrate body 21, and as a result, as shown in FIG. On the surface side, there is a portion 22 that contains almost no F as an impurity, or even if it does, contains significantly less violet than before heat treatment, and therefore exhibits low resistance. , a heat-denatured layer 24 having a surface @25 containing more F. on the portion 22 than before the heat treatment is formed. In this case, the thermally denatured layer 24 can be formed to have a thickness of 11 μm, with the portion 22 having a thickness of 4 μm and the surface portion 23 having a thickness of 11 μm.

Next, the semiconductor substrate body 21° is heat-treated to form a heat-denatured layer 24 on its surface side, and then the heat-denatured layer 24#c is etched using, for example, a bromine-methanol solution. 24 is removed to a sufficient thickness that at least the surface portion 23 is removed, and thus the heat-denatured layer 24 is removed on the surface side of the semiconductor substrate body 21.
The surface side of the heat-denatured layer 24 has a thickness sufficient to remove at least the surface portion 26, and a low-resistance semiconductor layer 25 is obtained by the remaining portion (the portion formed only by the above-mentioned portion 22). Therefore, ■-■ group compound semiconductor semiconductor board main body 2
A semiconductor substrate 26 having a structure in which a low resistance semiconductor layer 25 is formed on the front side of the semiconductor substrate 1 is obtained (FIG. 20).

Next, in order to form an accumulation type (MIa type) field effect transistor as a semiconductor element using the semiconductor substrate 26 obtained in this way, on the low resistance semiconductor layer 25 of the semiconductor substrate 26,
A source electrode 27 and a drain electrode 28 having a desired pattern are formed by vacuum evaporation treatment of, for example, a jku8n alloy.
For example, the low-resistance semiconductor layer 25 and the semiconductor substrate 26 are formed into ohmic contact with the low-resistance semiconductor layer 25 by heat treatment at 400° C. for 3 minutes in hydrogen gas, for example. For example, by mesa etching using a bromine-methanol solution, # reaches into the semiconductor substrate 26 through the entire thickness of the low resistance semiconductor layer 25 in the region between the source electrode 27 and the drain electrode 28.
At the same time as forming I51, an unnecessary region of the low resistance semiconductor layer 25 is removed (FIG. 2 113), and then an insulating layer 50 is formed to extend over the inner surface of the groove 51 and the subsequent surface of the low resistance semiconductor layer 25. Then, a gate electrode 29 is formed on the insulating layer 30 by using, for example, a vacuum evaporation process of 111, which can be extended to fj on the groove 51 (FIG. 2F). storage type (MIS) as a semiconductor device.
A desired semiconductor device is obtained by forming a field effect transistor (type) M2 (FIG. 2G).

The structure of another example of the semiconductor device according to the present invention (second example) has been described above.
Figure G) and an example of its manufacturing method have been revealed, but the structure of the semiconductor device according to the present invention makes it semi-insulating due to F as an impurity that forms a deep level. A semiconductor substrate 26 has a structure in which a low resistance semiconductor layer 25 is formed on the front side of a semi-insulating semiconductor substrate body 21 made of InP. Regions 32 separated by 1s51 of the low resistance semiconductor layer 25 using a semiconductor substrate
and 33 as a source region and a drain region, respectively, to form a semiconductor device consisting of an accumulation type (MIS type) m-field effect transistor M2, and in this case, the semiconductor substrate (semiconductor substrate 26) or the Since it is a semiconductor substrate using an insulating semiconductor substrate body (a 2°1 insulating semiconductor substrate body made of lnP which is semi-insulated by the addition of Fe as an impurity forming a deep unit),
As in the case of conventional semiconductor devices of this kind, a semiconductor element (storage type (MIS type) 11 formed using a semiconductor substrate)
This device has the characteristics that the field effect transistors M2) can be constructed as being separated from each other, and that the semiconductor element can be constructed as having a small stray capacitance.

However, in the case of the semiconductor device according to the present invention, the semiconductor substrate (semiconductor substrate 26) is composed of a semi-insulating semiconductor substrate body (made of InP made semi-insulating by adding F as an impurity to form a deep level). Impurity (Fe) that forms a deep level in the second layer of the l-■ group compound conductor substrate body
The low-resistance semiconductor layer (low-resistance semiconductor layer 25) is made of a ■-■ group compound semiconductor (InP) that is semi-insulating due to the addition number of .
The heat treatment ζ of the Kawa-V group compound semiconductor (Ink) made semi-insulating by the addition of . Since the surface side of the heat-denatured layer is the part left after the required thickness is removed, the low-resistance semiconductor layer (low-resistance semiconductor layer 25) has the required large thickness and shrinkage. It can be formed as having a specific resistance of 100%. Therefore, it is possible to form a semiconductor element (storage type (MlS type) field effect transistor M2) as having a corroboration performance. Incidentally, in the case of the top stripping according to the present invention, the mutual conductance is 70m5/
mm 2 O) value, which is much larger than that in the case where the low resistance semiconductor layer is formed by the epitaxial growth method as seen in the past.

Further, according to the embodiment of the method for manufacturing a semiconductor device according to the present invention described above in FIG. (see Figure 2), heat treatment is performed on the i+t-V group compound semiconductor substrate body 21 to form a heat-denatured layer 2 on the surface side of the side-I group compound semiconductor substrate body 21.
4 (FIG. 2B), remove the required thickness from the front side of the heat denatured layer 24, and then form the heat denatured layer 24 on the front side of the l-■ group compound semiconductor substrate body 21. , the required thickness from the front side of the heat-denatured layer 24 is removed to obtain a low-resistance semiconductor layer 25 by the remaining portion, and thus m-
A semiconductor substrate 26 having a structure in which a low-resistance semiconductor layer 25 is formed on the front surface side of a group (2) compound semiconductor substrate body 21 is obtained (second WAO), and the semiconductor substrate 26 is used to form a required semiconductor element (11 horizontal type). MIS type) field effect transistor M2
), it has the great feature that the semiconductor element having the above-mentioned high performance can be formed simply and easily.

In the above description, the main body of the insulating conductor substrate is made of a ■-V group compound semiconductor made semi-insulating by adding Cr or Fe as an impurity to form deep units. However, oxygen (
Even if the ■-■ group compound semiconductor is made semi-insulating by the addition of 0), the m-V group compound semiconductor may be Ga
Even if it is other than As or 1nP, it can also be used as a semiconductor device, Schottky junction type or accumulation type (MIS type).
Bipolar transistors other than field effect transistors,
It will be obvious that the present invention can be applied to diodes and the like.

[Brief explanation of the drawing]

1A to 1F show an example of a semiconductor device according to the present invention and an example of its manufacturing method. FIGS. FIGS. 3A and 3B are cross-sectional views illustrating sequential steps in an example of the manufacturing method, showing another example of a semiconductor device and an example of its manufacturing method. In the figure, 1 and 21 are semiconductor substrate bodies made of semi-insulated group III compounds, 4 and 24 are heat-denatured layers, 5 and 25 are low-resistance semiconductor layers, 6 and 26 are semiconductor substrates, and Ml is a Schottky junction. type field effect transistor, M2 is an accumulation type (MI
S type) I11 field effect transistors are shown respectively. Applicant Nippon Telegraph and Telephone Corporation

Claims (1)

[Claims] 1. In a semiconductor device in which a required semiconductor element is formed using a semiconductor substrate having a structure in which a low resistance semiconductor layer is formed on the surface side of a semi-insulating semiconductor substrate body, the above-mentioned The semi-insulating semiconductor substrate is made semi-insulating by adding impurities that form a deep level, and is made of a ■-■ group compound.
The low-resistance semiconductor layer is formed on the surface side of the I-III group compound semiconductor body by heat treatment of the Jokimon-V group compound semiconductor body. A semiconductor device characterized in that the thickness is determined by a portion left after being removed. 2. Prepare a semi-insulating semiconductor substrate made of a semi-insulating compound semiconductor substrate made of a semi-insulating material by adding impurities that form the Mori level, and heat-treat the compound semiconductor substrate to make it semi-insulating. A heat-denatured layer is formed on the surface side of the Arashi semiconductor substrate body, and the heat-density layer is removed to a required thickness and length, thereby forming the heat-density layer on the surface side of the Arashi-III group compound semiconductor body. The surface side of the heat-denatured layer is removed to a required thickness to obtain a low-resistance semiconductor layer by the remaining portion, and the above-mentioned layer is formed on the surface side of the l-V group compound semiconductor substrate body. A method for manufacturing a semiconductor device according to □, characterized in that a semiconductor substrate having a structure formed by forming a low resistance semiconductor layer is obtained, and a required semiconductor element is formed using the semiconductor substrate.