JPH0372680A - Semiconductor material, photoelectric integrated circuit element, and crystal growth method of material - Google Patents

Abstract

PURPOSE:To obtain semiconductor material wherein a GaAs or InP crystal layer of high quality is formed on an Si substrate, by arranging, directly or via a buffer layer, an Si or Si-Ge crystal layer on a GaAs or InP substrate. CONSTITUTION:GaAs based semiconductor material is formed as follows; an Si buffer layer 2 for lattice matching is formed on a GaAs substrate 1 by MOCJD and the like, and an Si crystal layer 3 is epitaxially grown on the buffer layer 2 by yo-yo solute supplying method. When a semiconductor device is constituted from said semiconductor material, the Si crystal layer 3 is used as an Si substrate, and the GaAs substrate 1 is used as a GaAs crystal layer. InP based semiconductor material is formed as follows; an Si buffer layer 2 is formed on an InP substrate 1, and further an Si crystal layer 3 is epitaxially grown by yo-yo solute supplying method. When a semiconductor device is made also from said material, an inverse mode is applied wherein the Si crystal layer 3 is used as an Si substrate, and the InP substrate 1 is used as an InP crystal layer.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a semiconductor material provided with a GaAs, i;l:InP or SiGe (hereinafter simply referred to as Sl) crystal layer on a top plate; The present invention relates to an optoelectronic integrated circuit device on which an optical device and an electronic device are integrated, and a crystal growth method of the material.

[Conventional technology]

■-Ga, which is a representative compound semiconductor material for group V binary alloys
As or InP is being commercialized or developed as a wide variety of semiconductor devices such as laser diodes, light emitting diodes, and ICs.

For example, as a device using GaAs, a semiconductor material is provided in which a GaAs crystal layer 53 is grown on a Si substrate 51 as shown in FIG. Note that the Si substrate 51 and G
A buffer layer 52 may be interposed between the aAs crystal layer 53 and the aAs crystal layer 53 in order to alleviate lattice constant mismatch.

In the case of InP, as shown in FIG.
A semiconductor material is provided in which an InP crystal layer 53 is grown directly or through a buffer layer 52 on the semiconductor material.

On this divine semiconductor material, there is also a Ga/l s system in the soil.
: It is used in various devices including 1lnP solar cells, but in order to further improve device performance, G
It is desirable that the aAs or InP crystal be of high quality.

In particular, in recent years, in the highly information-oriented society, it has become increasingly important to increase the functionality and performance of optical communication systems, and optoelectronic integrated circuit devices (OBICs), which are seen as promising for optical communication systems, are also becoming more and more highly functional. Quality GaAs or InP
Crystals are required.

An 0EIC is one in which optical elements such as a light receiving element and a light emitting element, and electronic elements such as a field effect transistor are monolithically integrated on a semiconductor substrate. For example, a repeater in an optical communication system converts an optical signal into an electrical signal using a light-receiving element, amplifies and shapes the electrical signal using an electronic element, applies the processed electrical signal to a light-emitting element, and converts it into an optical signal. Has the ability to convert again. - By integrating monolithic in boat fishing, it is possible to achieve greater functionality, higher performance, and lower costs. One important element for achieving higher levels of 0RIC is to improve the quality of the 0Etc substrate and the epitaxial film for optical devices.

[Problem to be solved by the invention]

In the GaAs-based semiconductor material having the structure shown in FIG. Although a buffer layer 52 such as a strained superlattice is interposed,
At present, the etch pit density (EPD) of a GaAs crystal layer with respect to a Si substrate is about 106/cJ, and there is a limit to the high quality of the GaAs crystal layer using conventional MOVPE.

The above also applies to the case of InP, and the EPD of an InP crystal layer with respect to a Si substrate is about 106/cJ.

As mentioned earlier, it is essential to improve the quality of the crystal to improve the performance of semiconductor devices such as 0EIC.In other words, it is essential to reduce the EPD value (at least 10
'/c-+i or less), and based on this, attempts are currently being made to obtain even higher quality GaAs or InP crystal layers.

Therefore, the object of the present invention is to produce high quality GaA on a Si substrate.
An object of the present invention is to provide a semiconductor material provided with a S or InP crystal layer, an OBIC 1 manufactured using the material, and a method for growing crystals of the material.

[Means to solve the problem]

In order to obtain a high-quality GaAs or TnP crystal layer on a Si substrate, the present inventors have conducted various studies and found that GaAs or TnP crystal layers can be grown using thin film crystal growth techniques such as ordinary MOVPE.
Although there is a limit to the quality improvement of As or InP crystal layers,
GaAs or InP substrates are made of high quality crystals (Ga
As substrate: EPD=IO'/cd or less, In
P substrate:EPD=IO:I/C-) is already available, and if this high quality GaAs or 1nP crystal substrate is used as a crystal layer, it will result in high quality GaAs or InP crystal layer. The first thing I focused on was whether it would be possible.

Based on this viewpoint, the present inventors proposed that, contrary to providing a GaAs or lnP crystal layer on a conventional Si substrate,
S on As or InP substrate (especially high quality single crystal substrate)
i or 5tGe (hereinafter simply referred to as Si) crystal layer [if necessary, insert a buffer layer between the two (first
), for GaAs-based or InP-based semiconductor devices, the fabricated semiconductor material can be used upside down; in other words, for GaAs-based devices, the Si crystal layer is
i-substrate, GaAs substrate as GaAs crystal layer, InP
In the system, the idea was to use a Si crystal layer as a Si substrate and an InP substrate as an InP crystal layer.

By the way, when manufacturing semiconductor devices, the substrate generally needs to have a thickness of at least about 200 μm or more, and S
In order to use the Si substrate as the i-crystal layer, it is necessary to grow the Si crystal layer to at least that thickness. However, G
When ordinary VPE, LPE, etc. are used to grow a Si crystal layer on an aAs or InP substrate, the thickness is limited to a few tens of microns at most, and it is extremely difficult to make the Sr crystal layer thicker than that. Have difficulty. Therefore, even if a Si crystal layer is grown on a GaAs or InP substrate, it is difficult to use the Si crystal layer as a substrate.

Therefore, as a result of further intensive research, the present inventors found that
A Si crystal layer is placed on a GaAs or InP substrate.

If epitaxial growth is performed using the yO solute supply method (details will be described later), the Si crystal layer will be at least 200 μm thick.
This makes it possible to use a Si crystal layer as a Si substrate.
It was discovered that it could be converted to a P crystal layer, and the present invention was completed.

That is, the present invention relates to a semiconductor material in which a Si crystal layer is provided directly or via a buffer layer on a GaAs or InP substrate, an optoelectronic integrated circuit element (OBIC) in which an optical element and an electronic element are integrated on the semiconductor material, and This is a crystal growth method for semiconductor materials in which a Si crystal layer is grown using a yo-yo solute supply method either directly on a GaAs or InP substrate or after growing a buffer layer.

In the present invention, y for GaAs or InP substrates.

By using the yO solute supply method, the Si crystal layer can be made thick (20
This means that Si
The crystal layer is a Si substrate, and the GaAs or InP substrate is a GaA substrate.
0BIC by using it as S or InP crystal layer
It is possible to achieve higher quality of semiconductor devices. In particular, the OBIC manufactured using the semiconductor material of the present invention is a Si-based LSI with electronic elements (FET etc.) integrated on the material.
The manufacturing process and the manufacturing process of optical elements (LD, photodiode, etc.) can be used as they are, making it easy to realize 0EIC.

The specific details of the yo-yo solute supply method will be described in the examples below, but the method is described in "Materials for Light-emitting Elements and Manufacturing Methods Therefor" (Japanese Patent Laid-Open No. 63-81989M, Japanese Patent Application No. 61-226275). ), which utilizes the fact that the gravitational field and the specific gravity of the solution depend on the concentration of solute contained in the solution, to form a desired crystal growth layer (Si crystal layer in the present invention). The name comes from the fact that the temperature is raised and lowered periodically to achieve this.

To briefly describe the growth of a Si crystal layer using this yo-yo solute supply method, a GaAs or InP 5 plate is placed above and a raw material Si polycrystal below.
Solvents with higher specific gravity (e.g. In, Sn, or B
(e.g.) is filled with a solution saturated with Si. Furthermore, by periodically raising and lowering the temperature, the lower Si polycrystals are supplied into the solution, and the GaAs or InP substrate side is provided with Si polycrystals.
A crystal layer will grow.

When growing a Si crystal layer on a GaAs or InP substrate using the yo-yo solute supply method, MOCVD, M.B.E.
It is preferable to provide a buffer layer using , VPE, or the like. The buffer layer in this case is SiSSi-Ge
, GaAs, or other materials may be used.

〔Example〕

Hereinafter, the semiconductor material of the present invention, 0EIC1, and the crystal growth method of the material will be explained in detail based on Examples.

GaAs-based semiconductor materials are GaAs-based semiconductor materials, as shown in FIG.
A St buffer layer 2 for lattice matching is formed on a MO substrate 1.
Formed by CVD etc., a Si crystal layer 3 is formed on the buffer layer 2.
was epitaxially grown using the yo-yo solute supply method.

Such a semiconductor material is used to fabricate a semiconductor device by forming the Si crystal layer 3 on a Si substrate or a Ga substrate, as in the conventional material shown in FIG.
As described above, the As substrate 1 is used as the GaAs crystal layer. In particular, if a high-quality single-crystal substrate is used as the GaAs substrate, the substrate will become a high-quality crystal layer, and the result will be the same as a high-quality GaAs crystal layer.

InP-based semiconductor material is an InP substrate 1 in FIG.
A St buffer layer 2 is provided on top, and a Si crystal layer 3 is provided on top.
This was epitaxially grown using the o-yo solute supply method. When this material is made into a device, the Si crystal layer 3 is used as a Si substrate and the InP substrate 1 is used as an InP crystal layer in an inverted manner.

The crystal growth method of the GaAs-based semiconductor material having the structure shown in FIG. 1 is carried out as follows using the yo-yo solute supply method.

First, the substrate is made of high-quality n-type GaAs that is currently commercially available.
Using a substrate (about EPD = 10''/c+fl), a buffer layer is grown on it by vapor phase epitaxy (MOVPE, MBE or VPE).The buffer layer includes MOVPE, MBE, or VPE.
A strained superlattice structure formed by BE method or a Si thin film formed by ordinary VPE method is used.

Next, Si was deposited on this substrate by the yo-yo solute supply method.
Grow a crystal layer. Growth temperature (900-800
Si saturates at a temperature approximately 10°C higher than
@Dissolve and use this as a growth solution. y.

-yo When growing the first layer using the solute supply method, in order to prevent meltback of the substrate, growth was started with supersaturation of about 10 °C, and the temperature was lowered at a cooling rate of 0.2 to 1.0 °C/min. The temperature will drop by about 50°C.

Thereafter, the temperature is raised again to the growth start temperature and the same temperature cycle is repeated about 30 to 50 times to grow a Si crystal layer of a desired thickness (about 200 μm).

The rnP semi-semiconductor material may be prepared in substantially the same manner using the yo-yo solute supply method.

Next, an example of 0EIC using the semiconductor material of the present invention will be explained based on FIGS. 2 and 3.

First, a high-quality GaAs substrate S' is prepared [Fig. 2 (a)
], a heterojunction AlG lattice-matched to the GaAs
The aAs layer 10 and the GaAs layer 11 are grown epitaxially on the GaAs substrate S' by LPE or the like [Second
See Figure (1))]. Here, the AlGaAs layer 10 acts as an etching guest rib when the substrate S' is removed by etching in a later step (e). next,
Si (or Si −
The G (!mixed crystal) layer 12 is grown epitaxially, preferably by VPE [see FIG. 2(C)]. The S1 layer 12
acts as a buffer layer.

Thereafter, as in the example of manufacturing the semiconductor material described above.

Si (or S
i-Ge) The crystal layer S is grown to a thickness of at least about 200 μm [see FIG. 2(d)]. As a result, the semiconductor material of the present invention as shown in FIG. 1 is obtained. In such a semiconductor material, in order to fabricate an 0BIC using a Si crystal layer S on a Si base substrate, the material is turned upside down and etched with G by, for example, an Nl1nOH: 1120□-based etchant.
The aAs substrate S' is removed by etching [see FIG. 2(e)]. Furthermore, the AlGaAs layer 10 is similarly removed using a 1-hydrofluoric acid etchant [see FIG. 2(f)].

Thereafter, optical and electronic components may be integrated on the semiconductor material using known OBIC fabrication techniques.

For example, basically the FET part is formed on the exposed S+ substrate, and the LD or photodiode part is formed on the GaAs (or GaP) layer. At this time, the optical element part becomes bulkier than the electronic element part, creating a step.
In order to solve this problem, it is possible to use means such as making the optical element part concave from the beginning or growing S3 on the Sine out part which becomes the electronic element part.

0EI manufactured using the semiconductor material shown in Figure 2(f)
An example of C is shown in FIG. In this material, GaAs layers 11 and 54 layers 12 of the electronic element portion are formed before device formation.
is removed by a suitable etching process to expose the Si crystal. This 0EIG has at least a ground layer (AIGaAs) 20 and an active layer (G
A multilayer including aAs, 'AlGaAs, etc.) 21 and a cladding layer (AIGaAs, etc.) 22 is epitaxially grown, and a striped electrode (n-type) 2 is further grown.
3, etc., the LD is made into a resonator structure by processing such as between the folds, and the n-type region 30 (the dopant is 5tXTe, etc.) and p4 are formed by existing techniques such as ion implantation on the exposed Si substrate S. A type region 31 (dopants such as Cd and Zn) is formed, and an electrode (n type, n
type, n-type) 32, 33, and 34. Note that an electrode (n type) 4 is also provided on the bottom surface of the S+ substrate S.
0 is set.

The above EIC is an example in which a GaAs substrate was used from the beginning of material production, but the structure is almost the same in the case of InP. For example, in the manufacturing process diagram shown in FIG. 2 when InP is used for the substrate S', the etching stopper layer 10 is made of Ga1.
nPAs, GaAs layer 11 is InP, cladding layer 20
．． 22 is Ga1nPAs, active layer 21 is JlGaPAs
It is recommended to replace it with

Note that the above 0BIC is only an example of the book, and the 0E of the present invention
It goes without saying that the IC is not limited to this.

〔Effect of the invention〕

Since the semiconductor material, 0EIC1, and the crystal growth method of the material of the present invention are configured as described above, they produce the effects described below.

Since a Si (or Si-Ge) crystal layer is grown on a GaAs or InP substrate using the yo-yo solute supply method, a thick Si crystal layer can be formed, and the Si crystal layer can be used as a Si substrate when manufacturing semiconductor devices. In particular, by using a high-quality single crystal substrate as a GaAs or InP substrate, it is possible to use GaAs for device fabrication.
Since the S or InP substrate can be used as it is as the GaAs or InP crystal layer, a high quality GaAs or InP crystal layer can be obtained very easily.

Furthermore, the 0BIC fabricated using the semiconductor material of the present invention can be used as is in the St-based LSI fabrication process for electronic elements (FET etc.) integrated on the material and the fabrication process for optical elements (LD, photodiode, etc.). ,0EIC
is easy to realize.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an example of the semiconductor material of the present invention produced by the yo-yo solute supply method, and FIG.
(f) is a process flow diagram showing an example of manufacturing a semiconductor material, FIG. 3 is a cross-sectional view showing an example of 0EIC using the semiconductor abrasive material of FIG. 2(f), and FIG. FIG. S': GaAs or InP substrate: Buffer layer: Si (or Si-Ge) crystal layer: Si crystal layer (substrate): GaAs substrate (crystal layer) 5 6 (a) (C) (e) Figure 2 (b) ) (d) (f)

Claims (3)

[Claims] (1) A semiconductor material characterized in that a Si or Si-Ge crystal layer is provided on a GaAs or InP substrate directly or via a buffer layer. (2) An optoelectronic integrated circuit device, characterized in that an optical device and an electronic device are integrated on the semiconductor material according to claim (1). (3) A crystal growth method for a semiconductor material, which comprises growing a Si or Si-Ge crystal layer on a GaAs or InP substrate directly or after growing a buffer layer using a yo-yo solute supply method.