JPS5951585A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To optimize the carrier-concentration distribution of an FET, and to manufacture an element easily by forming desired impurity-concentration distribution in the desired region of a semi-insulating substrate and forming a light- emitting or light-receiving region in the desired region. CONSTITUTION:Si ions are implanted selectively to the semi-insulating GaAs substrate 11, and a high-concentration N type GaAs layer 12 and an N type GaAs layer 13 are formed through heat treatment. Only a laser forming region is exposed and other sections except an exposed section 14' are protected by an insulating film 14, and an N type Ga1-xAlxAs (x=0.4) 15 to which Th is added, GaAs 16 not added in 0.2mum, P type Ga1-xAlxAs (x=0.4) 17 to which Ge is added and P type GaAs 18 to which Ge is added are formed by using a molecular beam epitaxy method. A P type electrode 20 consisting of Au-Zn is formed to P type GaAs 18 as a laser section, polycrystalline GaAs and GaAlAs are removed, and the insulating film 14 is exposed. Windows are bored to the insulating film 14, and a source electrode 21 using an Au-Ge alloy, a drain electrode 22 and a gate electrode 23 using an Al metal are formed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of manufacturing an optoelectronic integrated circuit in which optical devices and electrical devices are formed on the same substrate.

Optoelectronics integrated circuits, optical communications.

Data processing devices are attracting attention due to their miniaturization, high speed, etc. 8. Conventional configurations and their problems As an example of an optoelectronic integrated circuit, the integration of a laser and a FET (field effect transistor) will be explained.

FIG. 1 is an example of integrating a laser and FET using a semi-insulating substrate.

Semi-insulating GaAs (S-I-GaAs) substrate 1
Ga 1-xAl xAs (x
ζO64, undoped GaAgAs)2 is formed. This undoped GaAlAs2 acts as a heterostructure for confining laser light and at the same time
Works as a high resistance buffer layer. undoped GaA
Carrier concentration on lAs2 about 1017 cm-5, thickness ○
. n-type GaAs (n-Ga
As) 3 is formed by epitaxy cell growth. n-Ga
As 3 acts as an active region of a laser and FET. n
- p-type Ga 1-xA that becomes a ground layer on GaAs3
l xAs (x gull.4゜p -GaAlAs) 4
and p-type Ga for forming an ohmic contact layer.
As (p-GaA+ 36 is formed 1, these layers are formed using the liquid phase epitaxial method - Next, to form the laser and FET, using a mezae and a chimney, the FET forming part is formed as shown in Figure 1). And p-GaAs and p-GaAlAs in the peripheral area of the laser forming part are removed to selectively form p-GaAlAs4,4a and p-GaA.
Leave s5 and 5a. Mesa etching is performed using Au-Zn 6 as an electrode 6 which becomes the anode of the laser, a pad electrode 6a connected to the electrode 6, and a pad electrode 6 connected to the electrode 6.
By selectively forming Au-Zn as a, this Au-Zn
Etching was performed using n as an etching mask.

p-GaAlAs4a and p-GaAs5a become pad portions. In the FET, Au-Ge is formed on the exposed n-GaAs3 to form source S, drain D electrodes 7,
8, Al is provided as the gate electrode 9, and an FET is formed. When a forward voltage is applied to the laser, p −G
aAlAs n-GaA where holes from 4 are active regions
s3, electrons are injected from the drain region of the FET, and the n-GaA between the laser parts is used as the drain region.
s3, recombines in the active region of the laser section, and emits light l. The laser beam I is modulated by a voltage applied to the gate of the FET.

A drawback of the above manufacturing method is that the active region of the FET section is formed by the same epitaxial method as the active region of the laser, so that carrier concentration and thickness cannot be optimized.

Furthermore, since p-GaAs and p-GaAlAs are removed by etching and n-GaAs, which is the active region of the FET, is exposed, it is difficult to stop the etching at a desired thickness of n-type GaAs 3.

OBJECTS OF THE INVENTION The present invention provides a new method for manufacturing optoelectronic integrated circuits that eliminates the above-mentioned drawbacks.

Structure of the Invention The gist of the present invention is to form a desired impurity concentration distribution in a desired region of a semi-insulating compound semiconductor substrate, and then to form light emitting and light receiving regions in the desired region using an epitaxial method. Description of a certain 3° embodiment The present invention will be described below using GaAs as a substrate, laser and F
The integration of ET will be explained using an example. FIG. 2 is a cross-sectional view for explaining the present invention. Semi-insulating GaAs substrate 11
Then, using an ion implantation mask, ions of Sl were selectively implanted, and the implanted ions were activated at a rate of 1/1. Heat treatment is performed to harden the high concentration n-type GaAs layer 12.
An s-layer 13 is formed. The high concentration n-type GaAs layer 12 is made of FE
These become the source and drain regions of T and the high concentration n-type layer region of O/laser (FIG. 2a).

Only the laser forming region is exposed, and the other parts other than the exposed portion 14' are protected with an insulating film 14 (FIG. 2b). TI-doped n-type Ga1. ,,xAdx
As (x-0,4)15. Additive-free GaAs 16 to 0
・2 /Z rr+, Ge-added p-type Ga1-xA
lxAS(x-0,4)17, Ge-doped p-type Ga
As 18 is formed. Polycrystalline GaA is formed on the insulating film 14.
s, GaAlAs 19 is formed (Figure 2C).

A p-type electrode 2o made of Au-Zn is formed on the p-type GaAs 1 B of the laser section, and using the p-type electrode 20 as an etching mask, polycrystalline GaAs, Ga #As are formed.
is removed to expose the insulating film 14. A window is formed in the insulating film 14 using photolithography, and a source electrode 21 is formed using an Au-Ge alloy. A drain electrode 22 and a gate electrode 23 are formed using Al metal (FIG. 2d).

As is clear from the examples, the active region, source, and drain regions of the FET are made of semi-insulating GaAs using ion implantation.
Therefore, a carrier concentration distribution of the FET optimal for driving a laser can be formed.

The crystal formed by the epitaxial method is a single crystal in the laser part, and an insulating film is provided in the FET formation part so that polycrystals grow in the FET part, so only the polycrystal part can be easily grown without affecting the carrier concentration distribution in the FET part. can be removed. Further, in FIG. 1, since the FET is connected to the laser section through the active region, the series resistance between the laser and the FET increases, impairing high-speed modulation of the laser. - In the power tree embodiment, since it is connected to the laser part through the high concentration n+ region 2, the series resistance between the laser and the FET is reduced, and high-speed modulation of the laser is possible.

As described in detail, in order to form an optical device and an electrical device on the same substrate, the present invention forms a desired impurity concentration distribution in a desired region of a semi-insulating substrate, and then epitaxially coats the desired region. By forming a light emitting or light receiving region using a method, the carrier concentration distribution of the FET can be optimized, device fabrication becomes easier, and the performance of optoelectronics such as faster modulation speed can be improved. Its industrial value is that of a dog.

Although the manufacturing method for integrating a laser and FET has been described in the embodiment, it can also be used for integrating a photodetector and FET, a laser and a logic circuit, etc. InP, which was explained using GaAs, as a semi-insulating compound semiconductor substrate, Garb etc. may be used.Although the ion implantation method was explained as an impurity introduction method, a diffusion method or an epitaxial method may also be used.Molecular beam epitaxial method was used to form the laser part, but vapor phase epitaxial method etc. May be used. Although the FET was formed after removing the polycrystal on the insulating film, since the polycrystal on the insulating film has a higher resistance than a single crystal, the FET portion may be formed with the polycrystal remaining.

[Brief explanation of the drawing]

Figure 1 is a diagram of the integrated structure of a conventional laser and FET, Figure 2
Figures a to d are schematic diagrams of a laser and FET integrated manufacturing process according to an embodiment of the present invention. 11... Semi-insulating GaAs substrate, 12...
...High concentration n-type GaAs, 13...n-type G
aAs layer, 14... Insulating film, 15...
Tl-doped n-type Ga1-xAlxAs (x=0.4),
16-----.-Unadded GaAs, 17--Marked/Ge-added current Ga1xAexAs, 18...p-type GaAs -, 19... Polycrystalline GaA3 +
GaAlAs.

Claims (1)

[Claims] After selectively forming regions with different impurity concentrations on a semi-insulating substrate, an insulating film is provided in a desired part of the region, and a layer that emits or receives light is epitaxially applied to the region where the insulating film is not provided. A method for manufacturing a semiconductor device, characterized in that it is formed using a cell method.