JPH06232181A - Manufacturing method of Schottky junction field effect transistor - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] III-V containing In as a constituent element
In a method for producing a Schottky junction field effect transistor, which comprises a step of forming a gate electrode made of metal on the surface of a substrate or layer made of a group compound semiconductor so as to form a Schottky junction with the substrate or layer. After the step of applying the gate electrode on the surface of the substrate or layer, the Schottky characteristic is prevented from deteriorating even when the substrate or layer is kept at a relatively high temperature. A gate made of a refractory metal is used as the gate electrode in the step of attaching the gate electrode 10 on the surface of the substrate 1 or layer 2 in the method for manufacturing the Schottky junction field effect transistor described above. Use electrodes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate or a layer made of a III-V group compound semiconductor containing In as a constituent, and a gate electrode made of a metal on the surface of the substrate or the layer. The present invention relates to a method of manufacturing a Schottky junction field effect transistor having a structure in which a Schottky junction is formed between the Schottky junctions.

[0002]

2. Description of the Related Art Conventionally, a gate electrode made of metal is formed on a surface of a substrate or layer made of a III-V group compound semiconductor containing In as a constituent element by Schottky bonding with the substrate or layer. A Schottky junction field-effect transistor having a structure in which a metal is formed on a surface of a substrate or layer made of a III-V group compound semiconductor that does not contain In such as GaAs as a constituent element. The gate electrode made of is higher in function as a field effect transistor than a Schottky junction field effect transistor having a structure in which a Schottky junction is formed between the gate electrode and the substrate or layer. Various proposals have been made to obtain the functions.

Such a Schottky junction field effect transistor includes In as a constituent element III-
It is manufactured by including a step of forming a gate electrode made of metal on the surface of a substrate or layer made of a group V compound semiconductor so as to form a Schottky junction with the substrate or layer. In such a Schottky junction field effect transistor manufacturing method, conventionally, the substrate or layer contains In as a constituent element as the gate electrode in the step of attaching the gate electrode on the surface of the substrate or layer. A gate electrode made of a metal that is not a refractory metal, such as Ti or Pt, is used, which is similar to the case of using the same conventional Schottky junction field effect transistor manufacturing method in the case of using a III-V group compound semiconductor. Was used.

[0004]

However, in such a conventional method of manufacturing a Schottky junction field effect transistor, the substrate or layer is a III-V group compound semiconductor containing In as a constituent element, while Since the gate electrode is made of a metal that is not a refractory metal such as Ti or Pt, after the step of attaching the gate electrode on the surface of the substrate or layer,
When the substrate or layer is kept in a state of being heated to a relatively low temperature such as 200 ° C., that is, after the step of applying the gate electrode on the surface of the substrate or layer, for example, the substrate or layer To form a source electrode and a drain electrode on the surface of the substrate, and then to attach the source electrode and the drain electrode to the substrate or layer with good ohmic characteristics. To 200 substrates or layers
After the step of heating at a relatively high temperature of ℃ or more to alloy the source electrode and the drain electrode with the substrate or the layer, or the step of attaching the gate electrode on the surface of the substrate or the layer, An insulating film is formed on the surface of the substrate or layer, and the insulating film is formed on the surface of the substrate or layer.
The substrate or layer is heated to a temperature of 200 ° C. or higher due to the heat generated when the Schottky junction field effect transistor obtained by the step of forming by the CVD method is applied with a relatively high temperature of 0 ° C. or higher. In the case where it becomes, In as a constituent of the III-V group compound semiconductor forming the substrate or layer is alloyed with a metal that is not a refractory metal such as Ti or Pt forming the gate electrode. In an aspect, the substrate or layer and the gate electrode are alloyed.

Therefore, in the conventional method of manufacturing the Schottky junction field effect transistor described above, after the step of forming the gate electrode on the surface of the substrate or layer of the Schottky junction field effect transistor, the substrate or layer of 200 is formed. The characteristics of the Schottky junction between the substrate or the layer and the gate electrode, and therefore the Schottky junction field-effect transistor, when exposed to a relatively low temperature such as ° C. Only as a characteristic that deteriorates from the expected Schottky characteristic,
It cannot be manufactured, and if this is to be avoided, after the step of applying the gate electrode on the surface of the substrate or layer,
It has the disadvantage that the substrate or layer cannot be brought to a temperature above a relatively low temperature, such as 200 ° C., which is a limitation.

Therefore, the present invention does not have the above-mentioned drawbacks,
We propose a new Schottky junction field effect transistor manufacturing method.

[0007]

A method of manufacturing a Schottky junction field effect transistor according to the present invention includes In as a constituent element, as in the case of the conventional method of manufacturing a Schottky junction field effect transistor described above. There is a step of forming a gate electrode made of a metal on the surface of the substrate or layer made of a group V compound semiconductor so as to form a Schottky junction with the substrate or layer. A gate electrode made of a refractory metal is used as the gate electrode in the step of attaching the gate electrode on the surface.

In this case, the gate electrode made of a refractory metal may be a gate electrode made of WSiN type, WSi type, WN type, W, Mo, etc., among which the gate electrode made of WSiN type is used. It can be an electrode.

The substrate or layer is made of InGaP, I
The substrate or layer may be made of nGaAs or the like, but it is acceptable to use the substrate or layer made of InGaP.

[0010]

According to the method of manufacturing the Schottky junction field effect transistor of the present invention, after the step of applying the gate electrode on the surface of the substrate or layer, the substrate or layer is heated to a relatively low temperature of 200 ° C. or higher. Although it depends on the length of time in which the temperature is given even if the temperature of the substrate is set to a given value, in reality, if the temperature is a relatively high temperature such as 500 ° C. or lower, the substrate or layer Composing III
In, which is a constituent of the group-V compound semiconductor, hardly alloys with the metal forming the gate electrode.

Therefore, according to the method of manufacturing the Schottky junction field effect transistor of the present invention, after the step of forming the gate electrode on the surface of the substrate or the layer of the Schottky junction field effect transistor, the substrate or the layer of 200 is formed. Even if the temperature is kept at a relatively low temperature such as ℃, it actually depends on the length of time, but the temperature is actually below a relatively high temperature such as 500 ℃. At this temperature, the characteristics of the Schottky junction between the substrate or layer and the gate electrode, and thus the Schottky characteristics as a Schottky junction field effect transistor, are hardly deteriorated from the expected Schottky characteristics. Can be manufactured in
After the step of applying the gate electrode on the surface of the substrate or layer, the substrate or layer can be brought to a temperature above a relatively low temperature, such as 200 ° C., and thus, for example, the substrate or layer. After the step of applying the gate electrode on the surface of the substrate, the source electrode and the drain electrode are formed on the surface of the substrate or the layer, and then the source electrode and the drain electrode are formed on the substrate or the layer. The substrate or layer is heated to 200 ° C. to obtain a structure with ohmic properties.
After taking the step of alloying the source electrode and the drain electrode with the substrate or layer by heating at the above relatively high temperature, or after the step of attaching the gate electrode on the surface of the substrate or layer, the substrate Or form an insulating film on the surface of the layer,
At this time, the insulating film is formed on the substrate or layer at 200 ° C.
It is possible to take a step of forming by a CVD method in the state where the above relatively high temperature is applied, and the obtained Schottky junction field effect transistor is heated to generate a substrate or a layer of 200 ° C. or higher. It can be used in a state having the desired Schottky characteristic even at a relatively high temperature.

When the gate electrode made of a refractory metal used as the gate electrode is made of WSiN, the Schottky characteristics of the Schottky junction field effect transistor are different from those of the gate electrode other than WSiN. It is thermally stable as compared with a high melting point metal.

When the substrate or layer is made of InGaP, the Schottky characteristics of the Schottky junction field effect transistor show that the substrate or layer is made of InGaP other than InGaP.
Is obtained in comparison with the case where it is made of a III-V group compound semiconductor containing as a constituent element.

[0014]

EXAMPLES Next, examples of manufacturing the Schottky junction field effect transistor according to the present invention will be described with reference to FIGS.

In the method of manufacturing the Schottky junction field effect transistor according to the present invention shown in FIGS. 1 to 4, the intended Schottky junction field effect transistor is manufactured through the following sequential steps.

That is, a substrate 1 made of a III-V group compound semiconductor made of GaAs is prepared in advance (FIG. 1A).

Then, a layer 2 made of a III-V group compound semiconductor containing In by InGaP as a constituent element is formed on the substrate 1 by a known epitaxial growth method (FIG. 1B).

Next, a mask layer 4 having a required pattern is formed on the layer 2 by various methods known per se (FIG. 1C).

Next, by using the mask layer 3 for the layer 2 as a mask, an ion 5 of an impurity giving an n-type or p-type conductivity is implanted, which is known per se, so that the conductivity type is formed in the layer 2. An implantation region 6 of the ion 5 of the given impurity is formed (FIG. 1D). The figure shows a case where the ion implantation region 6 extends into the substrate 1.

The mask layer 4 is then removed from above the layer 2 by a method known per se (FIG. 2E).

Next, the heat treatment protective film 7 is formed on the layer 2 by a method known per se (FIG. 2F).

Then, the layer 2 forming the ion-implanted region 6 is heat-treated to form the active region 8 in which the ion-implanted region 6 is activated (FIG. 2G).

Next, the heat treatment protective film 7 is removed from the layer 2 by a method known per se (FIG. 2H).

Next, an insulating film 9 having a window 9a for exposing the active region 8 to the outside and made of, for example, SiO ₂ is formed on the surface of the layer 2 by a method known per se (FIG. 3).
I).

Next, on the surface of the layer 2, in the region of the active region 8 facing the window 9a of the insulating film 9, the gate electrode 10 made of a metal of a high melting point metal of WSiN system is itself provided. A Schottky junction 11 is formed between the active region 8 of the layer 2 and a known method (FIG. 3J).

Next, windows 9b and 9c for exposing the active region 8 to the outside at both positions sandwiching the gate electrode 10 are formed in the insulating film 9 by a method known per se (FIG. 3K).

Next, on the surface of the layer 2, in a region of the active region 8 facing the windows 9b and 9c of the insulating film 9, AuGe is formed.
The source electrode 12 and the drain electrode 13 are formed by a method known per se (FIG. 4L).

Next, the substrate 1 is heated at a relatively high temperature of about 400 ° C. for a time of about 1 to 2 minutes, and the source electrode 12 is heated.
And the drain electrode 13 is alloyed with the layer 2 and in the layer 2,
Form its alloyed regions 12 'and 13' (FIG. 4).
M). In the figure, alloyed regions 12 'and 1
3'is shown extending into the substrate 1.

Next, an insulating film 14 made of SiO ₂ is formed on the insulating film 9 by a known CVD method while the substrate 1 is heated at a relatively high temperature of 300 ° C. to 400 ° C. , Electrode 10, source electrode 12 and drain electrode 13
(FIG. 4N).

The above is the embodiment of the method of manufacturing the Schottky junction field effect transistor according to the present invention.

According to the method of manufacturing the Schottky junction field effect transistor of the present invention shown in FIGS. 1 to 4, after the step of applying the gate electrode 10 on the surface of the layer 2 (FIG. 3J), the source electrode 12 is formed. And alloying the drain electrode 13 with the layer 2 (FIG. 4M), and in the step, the layer 2
A relatively high temperature of about 400 ° C. above 200 ° C.
Let it stand for about 2 minutes, and layer 2
After the step of applying the gate electrode 10 on the surface of the layer (FIG. 3J), the step of forming the insulating film 14 on the surface of the layer 2 via the insulating film 9 is performed, and in that step, the layer is formed. 2 to 200
Although a relatively high temperature of 300 ° C. to 400 ° C., which is equal to or higher than 0 ° C., is applied for a relatively short period of time, the structure of the III-V group compound semiconductor forming the layer 2 is formed even in such a case. In as an element hardly forms an alloy with the WSiN-based metal forming the gate electrode 10.

Therefore, according to the method of manufacturing the Schottky junction field effect transistor according to the present invention shown in FIGS. 1 to 4, the Schottky junction field effect transistor is formed by the Schottky junction between the layer 2 and the gate electrode 10. Therefore, the characteristics of No. 11, that is, the Schottky characteristics as the Schottky junction field effect transistor hardly deteriorates from the expected Schottky characteristics, and can be easily manufactured. Further, the obtained Schottky junction field effect transistor (FIG. 4N) can be used in a state where it has desired Schottky characteristics even if the layer 2 is heated to a relatively high temperature of 200 ° C. or higher. .

This means that on the surface of the layer 2 the gate electrode 1
In the step of attaching 0 (FIG. 3J), the gate electrode 10 is
Instead of using a refractory metal made of SiN,
Regarding a Schottky junction field effect transistor manufactured by the same manufacturing method as the above-described Schottky junction field effect transistor shown in FIGS. 1 to 4 except that it is made of a metal that is not a refractory metal made of Pt. , Heating it, and heating the barrier height (eV) and n value (ideal factor) of the Schottky junction 11 between the layer 2 and the gate electrode 10 for that heating temperature (° C.) at each temperature. When the measurement was performed for 30 minutes, the results shown by the black dots in FIGS. 5 and 6 were obtained, while the Schottky junction field effect transistor according to the present invention shown in FIGS. 1 to 4 was manufactured. For the Schottky junction field effect transistor, the same barrier height (eV) and n value were measured under the same conditions.
It will be clear from the fact that the results shown by □ are obtained.

In the case of the method for manufacturing the Schottky junction field effect transistor according to the present invention shown in FIGS.
Since the gate electrode 10 is made of WSiN-based refractory metal and is attached to the layer 2, the obtained Schottky junction field effect transistor has Schottky characteristics that the gate electrode 10 is other than WSiN-based. WSi, W
It was confirmed that it is thermally stable as compared with the case where the layer 2 is made of a high melting point metal such as N, W or Mo.

Furthermore, since the layer 2 is formed of the InGaP system, the Schottky characteristics of the obtained Schottky junction field effect transistor show that the layer 2 is made of InGa.
It was confirmed that the obtained film was excellent in comparison with the case of being formed of InGaAs type other than P type.

In the above description, only a few examples of the present invention are shown, the substrate 1 is made of InGaP system, the layer 2 is omitted accordingly, and the substrate 1 in this case is It can be read as the layer 2, and the layer 2 is made of a III-V group compound semiconductor containing In such as InGaAs other than InGaP as a constituent element, and the gate electrode 11 is made of a material other than WSiN. It may be made of a melting point metal, and other various modifications and alterations may be made without departing from the spirit of the present invention.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view in a sequential process, which is used for explaining an embodiment of a method of manufacturing a Schottky junction field effect transistor according to the present invention.

FIG. 2 is a schematic cross-sectional view in a sequential process subsequent to the sequential process shown in FIG. 1 for explaining the embodiment of the method for manufacturing the Schottky junction field effect transistor according to the present invention.

FIG. 3 is a schematic cross-sectional view in a sequential process subsequent to the sequential process shown in FIG. 2 for explaining the embodiment of the method for manufacturing the Schottky junction field effect transistor according to the present invention.

4 is a schematic cross-sectional view in a sequential process subsequent to the sequential process shown in FIG. 3 for explaining the embodiment of the method for manufacturing the Schottky junction field effect transistor according to the present invention.

FIG. 5 is a schematic diagram of a Schottky junction field effect transistor manufactured by the method of manufacturing a Schottky junction field effect transistor according to the present invention shown in FIGS. 1 to 4; The result of measuring the barrier height (eV) of the Schottky junction between the gate electrode and the layer made of the III-V group compound semiconductor included as a constituent element is obtained according to the method for producing the Schottky junction field effect transistor according to the present invention. However, it is a figure shown in comparison with the same measurement result about the Schottky junction field effect transistor manufactured by a manufacturing method different from the manufacturing method of the Schottky junction field effect transistor according to the present invention.

FIG. 6 is a schematic diagram of a Schottky junction field effect transistor manufactured by the method of manufacturing a Schottky junction field effect transistor according to the present invention shown in FIGS. 1 to 4; The result of measuring the n value (ideal factor) of the Schottky junction between the layer made of a III-V group compound semiconductor included as a constituent element and the gate electrode was measured according to the method for producing the Schottky junction field effect transistor according to the present invention. However, it is a figure shown in comparison with the same measurement result about the Schottky junction field effect transistor manufactured by a manufacturing method different from the manufacturing method of the Schottky junction field effect transistor according to the present invention.

[Explanation of symbols]

 1 Substrate 2 Layer 4 Mask Layer 5 Ion 6 Ion Implantation Area 7 Heat Treatment Protective Film 8 Active Area 9 Insulating Film 9a, 9b, 9c Window 10 Gate Electrode 11 Schottky Junction 12 Source Electrode 12 ′ Alloyed Area 13 Drain Electrode 13 'Alloyed area 14 Insulation layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tatsuo Aoki 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation (72) Masami Tokumitsu 1-6-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corp. (72) Inventor Kazuyoshi Asai 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corp.

Claims (3)

[Claims] 1. III containing In as a constituent element
A Schottky junction field effect transistor having a step of forming a gate electrode made of metal on the surface of a substrate or layer made of a group V compound semiconductor so as to form a Schottky junction with the substrate or layer. In the manufacturing method, a gate made of a refractory metal is used as the gate electrode in the step of attaching the gate electrode on the surface of the substrate or layer.
A method of manufacturing a Schottky junction field effect transistor, characterized by using a gate electrode. 2. The method of manufacturing a Schottky junction field effect transistor according to claim 1, wherein the gate electrode made of the refractory metal is a gate electrode made of WSiN system. Manufacturing method of field effect transistor. 3. The method of manufacturing a Schottky junction field effect transistor according to claim 1, wherein a substrate or layer made of InGaP is used as the substrate or layer.