JPS6113659A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To shorten a manufacturing process by implanting Si ions to both or one metallic film of substrate regions forming p and n channel FETs through an ion beam mixing method. CONSTITUTION:An n-GaAs substrate 12 and a p-GaAs substrate 13 are formed onto a semi-insulating GaAs substrate 11. Gate electrodes 15 and 18 are shaped in predetermined regions in the substrate 12 and the substrate 13 by evaporating W silicide. Pt is evaporated simultaneously onto the substrate 12 and the substrate 13 through the patterning of a mask to each form source electrodes 14, 17 and drain electrodes 16, 19. Si ion beams are mixed with the electrode 14 and the electrode 16 shaped onto the substrate 12 as shown in the arrow. The ion beam mixing method particularly requires no mask. Ohmic layers 20 having low resistance in which Pt and Si are alloyed are formed through heat treatment. According to the method, the source and drain electrodes can be shaped simultaneously by the same material, thus shortening a manufacturing process.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an electrode of a semiconductor device in which n-channel and p-channel field effect transistors formed on a substrate of a gallium arsenide (GaAs) compound form a complementary circuit. This relates to a forming method.

A semiconductor device in which n-channel and p-channel field effect transistors are formed in a complementary circuit on a gallium arsenide substrate has excellent electrical performance such as high operating speed and low loss. is widely used.

In this semiconductor device, it is necessary to form source electrodes and drain electrodes ohmically in the p-channel field effect transistor and the n-channel field effect transistor, but in reality, the n-type gallium arsenide substrate on which each electrode is formed Because the doped impurities are different in the regions of the and p-type gallium arsenide substrates, the metal materials that form the ohmic electrodes with these substrates are limited.
It is impossible to form ohmic electrodes using the same metal material for both p-channel and n-channel field effect transistors.Currently, the electrodes are formed in each process using different metal materials. This complicates the manufacturing process and requires improvement.

[Conventional technology]

FIG. 2 is a cross-sectional view for explaining a semiconductor device in which a field effect transistor using a conventional gallium arsenide compound is formed into a complementary circuit. becomes n-
There are a GaAs substrate 2 and a p-GaAs substrate 3 that becomes a p-channel, and a source electrode 4.7, a gate electrode 5.8, and a drain electrode 6.9 are formed on the n GaAs substrate 2 and the p-GaAs substrate 3, respectively. There is.

As such an electrode material, in the case of the n-GaAs substrate 3, the ohmic electrode material of the source electrode 4 and drain electrode 6 formed on the n-GaAs substrate 2 is usually
Gold Gehermanium (AuGe) alloy, which forms an ohmic contact alloy with n-GaAs, is deposited by evaporation, and then gold (Au) is deposited on top of it at a temperature of 450°C.
It is heated to form an alloy (^uGe/Au).

This n-GaAs substrate 2 and ^uGe/^U alloy material are
The reason why the contact surface becomes ohmic is that when Gehrmanium reacts with the GaAs substrate, an ohmic interface of n-type semiconductor is generated, resulting in a low-resistance ohmic contact. .

On the other hand, as the ohmic electrode material for the source electrode 7 and drain electrode 9 formed on the p-GaAs substrate 3, a gold-zinc (AuZn) alloy, which easily forms an ohmic contact with the p-GaAs substrate 3, is usually used. - After depositing gold (Au) on the GaAs substrate 3, it is heated to a temperature of 350°C to 400°C to form an alloy (AuZ
n/Au), but in this case as well, zinc is GaAs
They react with the substrate to create a p-type semiconductor, and an ohmic interface is formed between these electrode materials and the substrate, allowing ohmic contact.

Gate electrode 4 is formed from a conventional Schottky material, such as tungsten silicide (WSi).

As described above, since the electrodes need to be formed using different electrode materials on the n-channel and p-channel substrates, there is a disadvantage that the manufacturing process for forming the electrodes is complicated.

FIG. 3 shows an equivalent circuit of a semiconductor device forming a complementary circuit, and the symbols correspond to those in FIG. 2. The connecting terminal is pulled out and a predetermined electrical operation is performed.

[Problem that the invention seeks to solve]

As a problem when manufacturing a semiconductor device in which a p-channel field effect transistor and an n-channel field effect transistor are formed in a complementary circuit on a semi-insulating substrate made of a gallium arsenide compound having the above structure, Because the properties of the p-channel and n-channel substrates are different, the same electrode materials cannot be used for the source and drain electrodes formed in field-effect transistors, which complicates the manufacturing process. There is a problem.

[Means for solving problems]

The present invention provides a semiconductor device that solves the above-mentioned problems, and its means is that a p-channel field effect transistor and an n-channel field effect transistor are formed as complementary circuits on a semi-insulating substrate made of a gallium arsenide compound. - forming a gate electrode in each of substrate regions forming the p-channel and n-channel field effect transistors;
A step of simultaneously depositing a source electrode and a drain electrode with the same metal film on each of the substrate regions where the channel and n-channel field effect transistors are to be formed, and on both the substrate regions where the p-channel and n-channel field effect transistors are to be formed. or a step of implanting silicon ions into one of the metal films by an ion beam mixing method,
This can be achieved by a method of manufacturing a semiconductor device characterized in that the metal film and the substrate of the p-channel and n-channel computer effect transistors form an ohmic electrode.

[Effect]

In the present invention, platinum (Pt) can be easily connected to a p-channel GaAs substrate in order to form an electrode connected by ohmic contact to both an n-channel GaAs substrate and a p-channel GaAs substrate formed on a gallium arsenide compound substrate. Focusing on the possibility of ohmic contact,
On the other hand, the ohmic connection between platinum and an n-channel GaAs substrate is achieved by implanting silicon into platinum using the ion beam mixing method, and by adding a high concentration of silicon (n-type impurity) to the alloy layer of platinum and the n-channel GaAs substrate. is injected to obtain ohmic characteristics.

Thus, the present invention provides n-channel GaA with the same metal.
This allows for ohmic contact with both the s-substrate and the p-channel GaAs substrate, and is designed to simplify the manufacturing process.

〔Example〕

1(a) to 1(C1) are cross-sectional views of the manufacturing process for explaining one embodiment of the present invention. 11 above,
There is an n-GaAs layer substrate 12 that will become an n-channel, and a p-GaAs substrate 13 that will become a p-channel.
A substrate 12 and a p-GaAs substrate 1 that becomes a p-channel.
3, a gate electrode 15 and a gate electrode 18 are formed in a predetermined area.
By patterning the resist mask and vapor deposition,
The thickness will be approximately 4,500 people.

FIG. 1 (bl is an n-GaAs substrate 12 and a p-GaA
By patterning the mask simultaneously with the s-substrate 13,
Platinum is formed by vapor deposition to a thickness of about 550 mm, and an n-
A source electrode 14.17 and a drain electrode 16.19 are formed on the GaAs substrate 12 and the p-GaAs substrate 13, respectively.

FIG. 1 (C1 is a platinum source electrode 14 and a drain electrode 16 formed on an n-GaAs substrate 12, so that the source electrode 14 and the drain electrode 16 are in ohmic contact with each other as shown by the arrows. In this method, silicon is mixed with an ion beam, and this ion beam mixing method does not require a mask because the implantation region can be limited to a small area.

The conditions for ion beam mixing of silicon ions are 1.
Generate an ion beam with an accelerating voltage of 40KeV and
After injecting lO”/afl, at a temperature of 800 °C, approximately 3
By performing the heat treatment for 0 minutes, a low resistance ohmic layer 20 made of an alloy of platinum and silicon is formed.

On the other hand, platinum for the source and drain electrodes formed on the p-GaAs substrate 13 has no problem because an ohmic alloy is easily formed with p-GaAs.

Thus, compared to conventional manufacturing processes, the present invention
- The drain and source electrodes formed on the GaAs substrate and the p-GaAs substrate can be formed simultaneously using the same material, which reduces the number of times masks are used in the manufacturing process, significantly shortening the manufacturing process. .

〔Effect of the invention〕

As explained in detail above, by employing the manufacturing method of the present invention, the manufacturing process can be shortened, thereby greatly contributing to the economical efficiency of manufacturing, which has a great effect.

[Brief explanation of the drawing]

1(al) to 1(e) are cross-sectional views for explaining the manufacturing process of the present invention. FIG. 2 is a cross-sectional view of a field effect transistor composed of a GaAs complementary circuit. An equivalent circuit diagram of a field-effect transistor composed of a circuit. In the figure, 11 is a semi-insulating substrate of gallium arsenide compound, 12 is an n-GaAs substrate that becomes an n-channel, and 13 is a semi-insulating substrate of a gallium arsenide compound.
15.18 is a gate electrode, 14.17 is a source electrode, 16.19 is a drain electrode, and 20 is an ohmic layer alloyed with platinum and silicon.

Claims (1)

[Claims] In a semiconductor device in which a p-channel field effect transistor and an n-channel field effect transistor are formed in a complementary circuit on a semi-insulating substrate made of a gallium arsenide compound, a substrate region in which the p-channel and n-channel field effect transistors are formed; each,
A step of forming a gate electrode, and a step of forming the p-channel and n-channel electrodes.
a step of simultaneously depositing a source electrode and a drain electrode with a metal film of the same quality on each of the substrate regions where the channel field effect transistor is formed; It consists of a step of implanting silicon ions into the metal film by an ion beam mixing method, and the metal film is
1. A method of manufacturing a semiconductor device, characterized in that ohmic electrodes are formed on substrate regions of channel and n-channel field effect transistors.