JPH06163399A - Manufacture of semiconductor substrate - Google Patents

Abstract

PURPOSE:To provide a method of fabricating a semiconductor substrate wherein heteroepitaxial growth is selectively achieved without causing any damage on a Si substrate. CONSTITUTION:An insulating film 2 is formed on a Si substrate 1, and is thereafter partly removed by irradiating it with a radical only at a portion where heteroepitaxial growth is effected. Further, only an exposed surface of the Si substrate 1 is selectively rendered to heteroepitaxial growth to form a compound semiconductor layer 3 and the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor manufacturing method,
In particular, the present invention relates to a method for manufacturing a semiconductor substrate including a step of selectively performing heteroepitaxial growth on a Si substrate.

[0002]

2. Description of the Related Art Conventionally, in a method of manufacturing a semiconductor substrate including a step of selectively performing heteroepitaxial growth on a Si substrate, as shown in FIG.
SiO ₂ is formed as an insulating film 2 on the i substrate 1. Si
The formation of O ₂ is performed by the well-known CVD method. this is,
For example, it is performed by reacting SiH ₄ and O ₂ at 300 to 400 ° C. Next, photoresist processing is performed in order to remove SiO ₂ in the portion where heteroepitaxial growth is performed. First, as shown in FIG. 2B, a photoresist film 4 having a uniform thickness is applied and formed on the wafer surface, and then the organic solvent remaining on the applied photoresist film 4 is removed and dried. 8 for proper curing
Prebaking is performed by raising the temperature to around 0 ° C. Then, the photomask 5 is exposed to ultraviolet rays so that the photomask 5 is aligned with the surface of the wafer in order to apply light to necessary portions. In FIG. 2C, 5a is a pattern portion of the photomask 5, and 4a is an unexposed portion in the resist film 4. Then, when the unnecessary photoresist film (unexposed portion) is removed with a solvent, the pattern of the photomask is transferred to the photoresist, as shown in FIG. after that,
In order to cure the photoresist film softened by the development and improve the adhesion with the substrate, the temperature is raised to around 150 ° C. and post-baking is performed.

Next, the remaining photoresist film 4 is used as a protective film to perform plasma etching on the wafer surface to form SiO 2.
_{2 The} film 2 is removed by etching as shown in FIG. CF ₄ gas is usually used for this etching. Finally, the hardened photoresist film 4 is removed by a method such as a solvent or plasma asher as shown in FIG. 2F, and the wafer is washed. As a result, the film 2 etched according to the pattern of the photomask remains on the Si substrate 1, and the Si surface of the other part is exposed. As shown in FIG. 2G, the compound semiconductor 3 is selectively heteroepitaxially grown on this wafer by, for example, the MOMBE method or the MOCVD method.

[0004]

However, as described above, when the photoresist processing is performed to remove the insulating film and the plasma etching is performed, the Si surface is damaged by the impact of ions and electrons in the plasma. . Already Si
If the element is formed on the substrate, it leads to deterioration of performance and destruction of the element. Especially in the case of MOS devices,
The gate insulating film is destroyed.

In view of such a situation, the present invention is based on S
It is an object of the present invention to provide a method for selectively performing heteroepitaxial growth on an i substrate without damaging it.

[0006]

In order to solve the above problems, the present invention is a method of manufacturing a semiconductor substrate including a step of selectively performing heteroepitaxial growth on a Si substrate, which comprises an insulating film on the Si substrate. Is formed, and thereafter, the insulating film is partially removed by radiating the radicals only to the portion where the heteroepitaxial growth is performed, and the heteroepitaxial growth is selectively performed only on the exposed Si substrate surface. And That is, in the case of the present invention, the removal of the insulating film is performed by radical irradiation.

The Si substrate for selectively performing heteroepitaxial growth according to the present invention is not limited to a specific one, but may be an unprocessed one or an Si substrate on which an insulated gate type MOS semiconductor element or the like is formed. is there. Examples of the heteroepitaxial growth layer include compound semiconductor layers such as GaAs.

[0008]

If the insulating film is removed by radical irradiation, the insulating film can be removed without using a resist. In removing the insulating film by radicals, Si by ions or electrons
No surface damage. Heteroepitaxial growth M
When the OMBE method is used, the main manufacturing process can be performed using a multi-chamber apparatus, and during that time, the substrate need not be exposed to the atmosphere even once. Therefore, the oxide film is not formed, it is not necessary to raise the temperature to remove the oxide film, and the growth temperature can be lowered.

[0009]

Embodiments of the present invention will be described below.
FIG. 1 shows an embodiment of the present invention. First, as shown in FIG. 1A, a SiO ₂ film 2 is formed on a Si substrate 1 by a known CVD method. Next, as shown in FIG. 1B, the S
The iO ₂ film 2 is removed using hydrogen radicals shown by the arrows. Generally, when an electric field is applied to a gas such as hydrogen to excite plasma, a group of ions, electrons and radicals can be formed. Therefore, by disposing an electrode capable of applying a positive and negative electric field between the plasma generation source and the sample, ions and electrons cannot pass through the electrode and only radicals can be extracted. Using this radical, the Si substrate 1
The SiO ₂ film 2 at an arbitrary place above is removed. When etching according to a pattern is to be performed, a sample stage (not shown) on which the substrate 1 is provided may be moved. In this way, the compound semiconductor layer 3 is selectively grown by the MOMBE method or the MOCVD method at the place where the SiO ₂ film is removed, as shown in FIG.

In the above-described embodiment, SiO is used as the insulating film.
_{Although 2} is used, it is not limited to this as long as it is an insulating film, and the forming method is not limited. Further, in the above-described embodiments, hydrogen gas is used as a radical generation source, but any gas can be used as long as it can etch the insulating film. Furthermore, the substance grown on the Si substrate is not limited to the compound semiconductor, and any substance that can be epitaxially grown may be used.

[0011]

As described above, according to the present invention, since the insulating film is removed by the radicals as described above, the step of photoresist processing is not required and the steps can be simplified. Further, when performing heteroepitaxial growth by the MOMBE method, the substrate is not exposed to the atmosphere, so that the growth temperature during epitaxial growth can be lowered. Furthermore, since radicals are used to remove the insulating film, the Si surface is not damaged by ions or electrons.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a manufacturing process of an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a conventional manufacturing process.

[Explanation of symbols]

1 semiconductor substrate 2 SiO ₂ film 3 compound semiconductor layer

[Procedure amendment]

[Submission date] February 1, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

[0009]

Embodiments of the present invention will be described below.
FIG. 1 shows an embodiment of the present invention. First, as shown in FIG. 1A, a SiO ₂ film 2 is formed on a Si substrate 1 by a known CVD method. Next, as shown in FIG. 1B, the S
The iO ₂ film 2 is removed using hydrogen radicals shown by the arrows. Generally, when an electric field is applied to a gas such as hydrogen to excite plasma, a group of ions, electrons and radicals can be formed. Therefore, by disposing an electrode capable of applying a positive and negative electric field between the plasma generation source and the sample, ions and electrons cannot pass through the electrode and only radicals can be extracted. This radical is used to remove the SiO ₂ film 2 at an arbitrary position on the Si substrate 1. When etching is to be performed according to a pattern, a sample stage (not shown) having the substrate 1 may be moved. Like this
As shown in FIG. 1C, the compound semiconductor layer 3 is selectively grown at the place where the SiO ₂ film is removed by the MOMBE method or the MOCVD method.

Claims (1)

[Claims] 1. A method for manufacturing a semiconductor substrate, which comprises a step of selectively performing heteroepitaxial growth on a Si substrate, wherein an insulating film is formed on the Si substrate, and then radicals are formed only at a portion where heteroepitaxial growth is performed. A method for manufacturing a semiconductor substrate, which comprises irradiating to partially remove the insulating film, and selectively performing heteroepitaxial growth only on the exposed Si substrate surface.