JPH03192719A - Compound semiconductor crystal growing method - Google Patents

Abstract

PURPOSE:To make it possible to conduct a selective growth mask patterning by a consistent vacuum process, and to expand the range of manufacturable element structure. CONSTITUTION:An oxide film 3 having a desired pattern is grown on the substrate crystal 1 of a III-V compound semiconductor, and the remaining part is left in an exposed state. Then, an epitaxial crystal growing operation is conducted at a temperature, at which the oxide film 3 is not desorbed, using two materials separately containing III group and V group component constituting the substrate crystal 1, as raw material, and crystal is selectively grown on the exposed part using the oxide film 3 as a mask. In other words, the patterning of the mask for selective growth can be conducted by a vacuum process by making combinations of the properties of GaAs surface and the GaAs surface oxide film 3. Also, as the oxide film 3 can be removed by heating in an As atmosphere, crystal can be regrown on the part where the mark is present. As a result, the range of structure of element, which can be manufactured using a selective growth mask, can be extended.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for growing crystals of compound semiconductors.

[Prior art] The oxide film on the surface of AfIAs is used as a mask for selective growth.
An example of selective growth of As will be explained with reference to FIG.

A as a mask material for selective growth on the GaAs substrate crystal 5
IAsa6 is grown as a crystal (a). Next, G is etched onto the crystal surface of the substrate by photolithography, etching, etc.
A structure is formed in which exposed surfaces 7 of aAs and AfIAs appear (b). When this substrate crystal is heated in an oxygen atmosphere, oxide films 8.9 are formed on the GaAs and AlAs surfaces of the substrate crystal (C). Next, when this substrate crystal is heated in an As atmosphere, only the GaAs oxide film is removed, and an AlAs oxide film 9 and an exposed GaAs surface 7 of the substrate appear on the substrate crystal surface (d). MOCV
When GaAs crystals are grown by D (organic metal vapor phase epitaxy), the GaAs crystal 1 grows within a certain growth temperature range.
0 is the GaAs substrate crystal surface 7 exposed by substrate heating.
grows on (e).

[Problem to be solved by the invention] The above-mentioned conventional technology has the following problems.

That is, (1) contamination of the substrate crystal surface by photoresist etc. is unavoidable when patterning the mask for selective growth, and (2) the AfIA used as the mask for selective growth cannot be avoided.
Since it is difficult to remove the oxide film on the s surface by heating, the device structures that can be manufactured using the selective growth mask described above are limited.

(3) The growth temperature to prevent GaAs from regrowing on the oxide film on the ANAs surface is limited, making it difficult to lower the process temperature, and (4) it is necessary to grow crystals for selective growth masks. was there.

In view of the drawbacks of the conventional methods described above, the crystal growth method of the present invention allows for crystal growth in which the mask can be easily removed by heating without contaminating the substrate crystal, and recrystallization on the mask can be prevented at a relatively low temperature. It is an attempt to obtain the law.

[Means for Solving the Problems] According to the present invention, a step of growing an oxide film in a desired pattern on a substrate crystal of an mlV compound semiconductor and leaving the remaining portion exposed, and forming the substrate crystal. A step of performing epitaxial crystal growth on the exposed portions using the oxide film as a mask using two materials separately containing two components of the group (III) and group (III) as raw materials at a temperature at which the oxide film does not desorb. A compound semiconductor crystal growth method including the following is obtained.

Further, according to the present invention, after the above two steps.

A compound semiconductor crystal growth method is obtained which includes a step of removing the oxide film of the mask by heating the crystal substrate in an atmosphere of the group V component at a temperature at which the oxide film is desorbed.

[Operation] When the surface of GaAs is irradiated with light in an oxygen atmosphere, a GaAs oxide film can be formed only on the portions exposed to the light.

Further, by irradiating the oxide film on the GaAs surface with an electron beam in a chlorine atmosphere, the oxide film can be removed only in the portions hit by the electron beam.

By combining the properties of the GaAs surface and the GaAs surface oxide film described above, patterning of a mask for one selective growth becomes possible in a vacuum process.

Furthermore, since the oxide film on the GaAs surface can be easily removed by heating in an As atmosphere, it becomes possible to re-grow the GaAs at the location where the selective growth mask was located, which was difficult in the prior art. Therefore, there are fewer restrictions on the device structure that can be manufactured by turning the mask for selective growth.

By using the above-mentioned crystal growth raw materials and crystal growth method, the substrate temperature range in which selective growth can be performed is expanded, and the temperature of the process can be lowered.

[Example] As a raw material for crystal growth, TMG ()limethylgallium)
and MOMBE (organometallic molecular beam epitaxy) using As4. An example will be explained by taking selective growth of GaAs as an example.

GaAs substrate crystal 1 at room temperature in an oxygen atmosphere.

Irradiate with Ar laser light 2. At this time, the oxidation of the GaAs substrate crystal surface irradiated with the Ar laser beam is promoted, and the GaAs
An s oxide film 3 is formed (a).

Next, QaAs crystal is grown on the GaAs substrate crystal 1 by the MOMBE method using TMG and As4 as raw materials. At this time, GaAs crystal 4 is selectively grown in a region other than GaAs oxide film 3. The growth temperature must be kept at a maximum of 630°C to prevent the GaAs oxide film 3 from desorbing (
b).

After crystal growth is completed, when the GaAs substrate crystal is heated to 630°C or higher in an atmosphere of group V As with high vapor pressure, G
The aAs oxide film 3 can be removed, and as shown by la, the GaA
The s-substrate crystal 1 is exposed.

A regrown GaAs crystal 4a can be formed on the exposed surface 1a from which the GaAs oxide film has been removed (d).

In the above embodiment, a case was described in which a selective growth mask was formed by utilizing the progress of oxidation of the GaAs surface in areas exposed to light. In addition to this, what happens when a GaAs oxide film is irradiated with an electron beam in a chlorine atmosphere? A mask for two-selective growth can also be formed by taking advantage of the ability to remove the GaAs oxide film in the area irradiated with the 11-element beam.

In the above embodiment, GaA4 crystal was described as an example of the mlV group, but other mlV group crystals such as ANP, In
It can also be applied to Sb, etc. The desorption temperature of the oxide film and the use of a Group V element with a high vapor pressure for removing the oxide film can be handled in exactly the same way.

[Effect of the invention] The effects of using the present invention will be described below.

(1) Formation of a mask for selective growth by using an oxide film on the GaAs surface as a mask for selective growth - Selective growth -
Removal of the selective growth mask and regrowth can be performed as a vacuum-through process. Therefore, the substrate crystal surface is not contaminated by the atmosphere, photoresist, etc.

(2) The oxide film on the GaAs surface used as a mask for selective growth can be easily removed by heating the substrate crystal.
The range of device structures that can be manufactured is expanded.

(3) Since the growth temperature range in which regrowth does not occur on the oxide film on the substrate crystal surface can be extended to the lower temperature side, the process temperature can be lowered.

(4) It is not necessary to grow a crystal only for the mask for selective growth, so the process can be simplified.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the selective growth and regrowth process according to the present invention, and FIG. 2 is a diagram showing the selective growth and regrowth process according to the prior art. Explanation of symbols: 1 is a GaAs substrate crystal, la is an exposed surface of a GaAs substrate crystal, 2 is an Ar laser beam, 3 is a GaAs oxide film, 4 is a GaAs crystal, and 4a is a regrown GaAs crystal. Figure 1 10 GaAs substrate crystal exposed surface Figure 2 Procedure amendment (voluntary) March 19, 1990

Claims (2)

[Claims] (1) A step of growing an oxide film in a desired pattern on a substrate crystal of a group III/V compound semiconductor and leaving the remaining portion exposed;
A compound semiconductor comprising the step of: performing epitaxial crystal growth using two materials separately containing two components of the group as raw materials at a temperature at which the oxide film does not desorb, and selectively growing on the exposed portion using the oxide film as a mask. Crystal growth method. (2) A step of growing an oxide film in a desired pattern on a substrate crystal of a group III/V compound semiconductor and leaving the remaining portion exposed;
a step of performing epitaxial crystal growth using two materials separately containing two components of the group as raw materials at a temperature at which the oxide film does not desorb, and selectively growing on the exposed portion using the oxide film as a mask; a step of removing the oxide film of the mask by heating the mask in an atmosphere of the Group V component at a temperature at which the oxide film is desorbed.