JPH03218676A - Electrode for compound semiconductor and its manufacturing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an electrode for compound semiconductors that can be used as an electrode for compound semiconductor devices with excellent high-speed performance required for advanced information processing and communication systems, and a method for manufacturing the same. It is related to.

BACKGROUND OF THE INVENTION With the recent development of a highly information-oriented society, there is an increasing need for higher frequencies in the communications field, as well as higher speeds and larger capacities in the information processing field. In order to achieve these goals, research and development efforts are being actively conducted to increase the speed and integration of semiconductor devices using compound semiconductors.

Here, in order to obtain the high-speed performance inherent to compound semiconductors,
It is necessary to reduce parasitic resistance and capacitance. While element miniaturization is effective in reducing parasitic capacitance, when miniaturization progresses to a certain extent, the contact area between the semiconductor and the electrode decreases, leading to an increase in contact resistance, leading to an increase in parasitic resistance. Therefore, it is important to develop electrodes with low contact resistance.

Hereinafter, a conventional compound semiconductor electrode and its manufacturing method will be described with reference to the drawings.

FIG. 2 is a structural sectional view showing a conventional compound semiconductor electrode, and FIG. 3 is a heat treatment temperature characteristic curve of contact resistivity in the conventional method and the method of manufacturing a compound semiconductor electrode according to the present invention.

In FIG. 2, 1 is a GaAs semi-insulating substrate, 2 is a p-type GaAs layer, and 3 and 4 are an AuZn alloy layer and an Au layer, which serve as electrodes of the p-type GaAs layer 2, respectively.

A conventional compound semiconductor electrode having the above structure and a method for manufacturing the same will be described below.

First, a p-type GaAS layer 2 (
Impurity concentration: 4xlO"c+r", film thickness: I00n
m) is coated with an AuZn layer 3 (Zn:
5vt%) and an Au layer 4 with a thickness of 10 Qnm is formed by vacuum evaporation. Next, an electrode for the p-type GaAs layer 2 made of the metal multilayer film is completed by heat treatment in an infrared furnace. (For example, Krohn et al., The Journal of the Electrochemical Society, Vol. 116, pp. 507-5.
08 pages, 1969 (The Journal of
Electrochemical Society
s Vol. 118, pp507-508 (1
989)) Reference. ) Figure 3 shows the dependence of the contact resistivity of the AuZn/Au-based electrode obtained as described above on the temperature of the heat treatment (the heat treatment time was 20 seconds). When the heat treatment temperature ranges from about 340°C to 400°C, the contact resistivity is about 0.9x10-6.
Ωcm2 to 1. A low value of OxlO "Ωcm" is obtained.

Problems to be Solved by the Invention However, with the above configuration and method, heat treatment at approximately 350°C for 20 seconds is required to obtain a low contact resistivity, as shown in FIG. , 40
Heat treatment at 0° C. or higher causes a rapid increase in contact resistivity. For this reason, the heat treatment for obtaining low contact resistivity needs to be performed accurately within the narrow temperature range of about 350°C to about 400°C. In addition, in the semiconductor device manufacturing process, it is of course impossible to apply a process that requires heat treatment at 400°C or higher after forming this electrode, and even if the temperature is lower than this, long-term heat treatment is generally higher than that. Since it has the same effect on the electrode as short-time heat treatment at high temperatures, for example, the normal passivation film formation process (approximately 300°C, about 1 hour) is a factor that increases the contact resistivity of this electrode. The problem was that there was a possibility that

In view of the above-mentioned problems, the present invention provides lower contact resistivity at a lower heat treatment temperature than conventional methods, a wider range of heat treatment temperatures for obtaining low contact resistivity, and easier temperature control for heat treatment. The present invention provides an electrode for a compound semiconductor and a method for manufacturing the same, which makes it possible to keep the contact resistivity of the electrode low even in a semiconductor element manufacturing process that involves heat treatment after electrode formation.

Means for Solving the Problems In order to solve the above-mentioned problems, the compound semiconductor electrode of the present invention and its manufacturing method have a p-type -
(2) An electrode for a group compound semiconductor, the p-type II
It has an NNI layer between the IV group compound semiconductor and the Zn layer or the AuZn alloy layer, and its manufacturing method involves forming an Ni layer, Zn layer or AuZn alloy layer on the p-type ■-■ group compound semiconductor. The method includes the steps of forming a metal multilayer film consisting of an Au layer and an Au layer in this order by vacuum evaporation, and heat-treating the p-type ■-■ group compound semiconductor having the metal multilayer film in an infrared furnace. be.

Effect of the Invention In the present invention, with the above-described configuration and method, lower contact resistivity can be obtained at a lower heat treatment temperature than in the past, and the temperature control of the heat treatment can be easily controlled, and semiconductor elements that require heat treatment after electrode formation can be obtained. Even in the manufacturing process, it is possible to maintain the contact resistivity of the electrode at a low level.

EXAMPLE Hereinafter, an electrode for a compound semiconductor and a method for manufacturing the same as an example of the present invention will be described with reference to the drawings.

FIG. 1 is a structural cross-sectional view showing an electrode for a compound semiconductor according to an embodiment of the present invention, and FIG. It is a heat treatment temperature characteristic curve diagram of contact resistivity.

First, referring to FIG. 1, an electrode for a compound semiconductor and a method for manufacturing the same in one embodiment of the present invention will be described below. Note that in FIG. 1, part of the structure is the same as the conventional compound semiconductor electrode shown in FIG.
Identical components are given the same numbers.

In FIG. 1, 1 is a GaAs semi-insulating substrate, 2 is a p-type GaAs layer, and 5, 6, and 7 are a Ni layer, a Zn layer, and an Au layer, which serve as electrodes of the p-type GaAs layer 2, respectively.

First, a p-type GaAS layer 2 (
Impurity concentration: 4xl019c'3, film thickness: 100n
m) with a Ni layer 5 having a thickness of 50 nm and a Ni layer 5 having a thickness of 40 nm.
A metal multilayer film consisting of a Zn layer and an Au layer 7 with a thickness of 40 nm is formed by vacuum evaporation. Next, an electrode for the p-type GaAs layer 2 made of the metal multilayer film is completed by heat treatment in an infrared furnace.

Next, using FIG. 3, the dependence of the contact resistivity of the old/Zn/Au based electrode of one example of the present invention obtained as described above on the temperature of the heat treatment (heat treatment time is 20 seconds)
shows. In a wide range of heat treatment temperatures from about 200°C to 460°C, the contact resistivity is 1. A low value of less than OxlO-"ΩQm" was obtained, and the contact resistivity was approximately 0.7xlO-"ΩcII1 especially when the heat treatment temperature was around 330°C.
2 is obtained.

As described above, according to the embodiment shown in FIG. 1, as is clear from FIG.
), the heat treatment temperature is lower than that of 1. OxlO-6
A low contact resistivity of Ωcm2 or less can be obtained. Also, 1
．． There is a wide range of heat treatment temperatures at which a low contact resistivity of OxlO-"ΩcII12 or less can be obtained, making it easier to control the temperature of the heat treatment. Furthermore, the degree of increase in contact resistivity due to heat treatment at a high temperature of approximately 500°C or higher is lower than that of conventional methods. Since this is relatively gentle, it is possible to maintain the contact resistivity of the present electrode lower than in the past even in the semiconductor element manufacturing process that involves heat treatment after the formation of the present electrode.

In the above embodiment shown in FIG. 1, the NI layer is p-type
- Although the Zn layer is formed between the group compound semiconductor and the Zn layer, the Zn layer may be any layer that serves as a supply source of Zn, for example, A
It may also be a uZn alloy layer.

Effects of the Invention As described above, the compound semiconductor electrode and the manufacturing method thereof of the present invention are electrodes for p-type ■-■ group compound semiconductors as the electrode structure, and the electrodes include the p-type III-V group compound semiconductor and the Zn layer. Alternatively, it is characterized by having a Ni layer between it and the AuZn alloy layer, and its manufacturing method includes p-type ■
-Ni layer, Zn layer or Au layer on the ■group compound semiconductor
A step of forming a metal multilayer film consisting of a Zn alloy layer and an Au layer in that order by vacuum evaporation; and a step of heat-treating the p-type ■-■ group compound semiconductor having the metal multilayer film in an infrared furnace. Features.

By using the electrode for compound semiconductors and the manufacturing method thereof of the present invention, lower contact resistivity can be obtained at a lower heat treatment temperature than before, and the temperature of the heat treatment can be easily controlled immediately, and the heat treatment after forming the electrode can be performed easily. Even in the semiconductor device manufacturing process involving the above, it is possible to maintain the contact resistivity of the electrode at a low level.

[Brief explanation of drawings]

FIG. 1 is a structural cross-sectional view showing a compound semiconductor electrode according to an embodiment of the present invention, FIG. 2 is a structural cross-sectional view showing a conventional compound semiconductor electrode, and FIG. 3 is a structural cross-sectional view showing the conventional compound semiconductor electrode and the present invention. FIG. 3 is a diagram showing a heat treatment temperature characteristic curve of contact resistivity in the method for manufacturing an electrode for a compound semiconductor. 1...GaAs semi-insulating substrate, 2...p-type GaAs
3... AnZn alloy layer, 4, 7... Au layer, 5... Ni layer, 6... Zn layer.

Claims (5)

[Claims] (1) An electrode for a p-type III-V group compound semiconductor, characterized in that it has a Ni layer between the p-type III-V group compound semiconductor and a Zn layer or an AuZn alloy layer. electrode. (2) The electrode for a compound semiconductor according to claim 1, wherein the III-V group compound semiconductor is made of GaAs. (3) Ni layer, Zn layer on p-type III-V group compound semiconductor
a step of forming a metal multilayer film consisting of a layer or an AuZn alloy layer and an Au layer in this order by a vacuum evaporation method; and a step of heat-treating the p-type III-V group compound semiconductor having the metal multilayer film in an infrared furnace. A method for producing an electrode for a compound semiconductor, comprising: (4) The method for manufacturing an electrode for a compound semiconductor according to claim 3, wherein the heat treatment is performed at a temperature range of 200° C. to 460° C. for 20 seconds. (5) The method for manufacturing an electrode for a compound semiconductor according to claim 3, wherein the III-V compound semiconductor is made of GaAs.