JPH04303923A - Method of forming selectively grown, buried semiconductor - Google Patents

Abstract

PURPOSE:To provide a title method whose fineness degree is sufficient for manifesting a quantum effect and which does not cause damage in a processing operation. CONSTITUTION:A silicon oxide film 14 haivng a thickness of 300Angstrom is formed, by an electron beam vapor deposition method, on the surface of a GaAs substrate 11 on which an AlGaAs layer 12 having a thcikness of 2mum and a GaAs cap layer 13 having a thickness of 300Angstrom have been laminated. Then, while xenon fluoride gas 17 is being supplied, the silicon oxide film 14 is irradiated with a focused ion beam 16. Thereby, an opening part 18 can be formed. Then, when a showerlike electron beam 19 is irradiated through the opening part in the atmosphere of chlorine, the surface of the GaAs substrate directly under the opening part 18 is etched efficiently. GaAs 22 can be buried and selectively grown in an etched part 21 formed in this manner by using a metal organic vapor growth apparatus and, in addition, by making use of the silicon oxide film (SiO2) 14 as a mask in a selective growth operation.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for selectively implanting crystal growth in a semiconductor substrate.

0002

[Prior Art] Selective buried crystal growth on a semiconductor substrate;
For example, selective buried crystal growth of AlGaAs on a GaAs substrate is expected to be a technology for integrating opto-electronic devices. As a conventional technique for this selective implantation growth, there is a method of selectively implanting AlGaAs onto a GaAs substrate using low pressure metal organic vapor phase epitaxy (MOVPE).
A document by Koichi Komon et al. published in the July 1985 Proceedings “
"Selective growth of GaAs and AlGaAs by low pressure OMVPE".

According to this document, Si is used as a selection mask.
A Nx film is deposited on a GaAs substrate by plasma CVD for approximately 10
It is used by depositing 00 Å. Next, a striped pattern with a width of 5 to 10 μm was formed on the SiNx by photolithography.
Formed into a film and further 4H2 SO4 :H2 O2 :
A groove with a depth of 5 μm is formed by etching in H2O solution. The growth apparatus is a resistance heating type vertical reactor, and trimethylaluminum (TMA), trimethylgallium (TMG), and AsH3 are used as raw materials. The growth is
Pressure 0.1-10 Torr, substrate temperature 650-770°C
, at a total flow rate of 300 to 500 sccm.

0004

[Problem to be solved by the invention] In recent years, processing has become finer and processing dimensions of 1000 Å or less have been realized.
This processing dimension is an area in which quantum effects are expected. Therefore, quantum wires and quantum boxes can be realized by performing embedded selective growth with a pattern of 1000 Å or less. However, since the semiconductor substrate is wet-etched in the buried selective growth described above, miniaturization is difficult. Furthermore, even if the etching of the SiNx film and semiconductor substrate is changed to dry etching, the resist layer on the SiNx film is patterned by electron beam lithography, etc., and this is used as a mask to
It is necessary to dry-etch the x film to transfer the fine pattern, and then dry-etch the GaAs substrate using the SiNx film as a mask to transfer the fine pattern. However, with this method, it is actually difficult to accurately transfer a fine pattern of 1000 Å or less twice.

[0005] An object of the present invention is to provide a buried selective growth method that has sufficient fineness to make quantum effects apparent and is free from processing damage.

[0006]

[Means for Solving the Problems] The buried selective growth method of a semiconductor according to the present invention is a method of buried selective growth of a semiconductor on a III-V group compound semiconductor substrate.
A silicon oxide film (SiO2
) or a silicon nitride film (SiNx); a step of performing maskless etching on the silicon oxide film (SiO2) or silicon nitride film (SiNx) in a reactive gas or radical atmosphere containing fluorine atoms; selectively dry etching the compound semiconductor substrate in a reactive gas or radical atmosphere containing halogen atoms using a silicon oxide film (SiO2) or silicon nitride film (SiNx) as a mask; or silicon nitride film (SiNx
) is used as a mask to perform a buried selective growth method of a semiconductor on the etched portion of the compound semiconductor substrate.

[0007]

[Operation] In the present invention, a silicon oxide film (SiO2) or a silicon nitride film (SiNx) on the surface of a III-V compound semiconductor substrate is etched into a fine pattern by maskless etching in a reactive gas or radical atmosphere containing fluorine atoms. By using this patterned silicon oxide film (SiO2) or silicon nitride film (SiNx) as a mask for both dry etching and selective buried growth of compound semiconductors, it is possible to selectively fill fine areas in a simple process. Growth can be achieved.

[0008]

[Embodiment] An embodiment of the present invention will be shown in FIG. 1 with cross-sectional views showing each step. As shown in FIG. 1(a), a 300 Å thick silicon oxide (SiO2) film 14 is formed on the surface of a GaAs substrate 11 on which a 2 μm thick AlGaAs layer 12 is further laminated with a 300 Å thick GaAs cap layer 13.
is provided by electron beam evaporation. Next, as shown in the same figure (b), xenon fluoride (XeF2
) By irradiating the silicon oxide film (SiO2) 14 with a 5 KeV focused electron beam 16 while supplying a gas 17, the silicon oxide film (SiO2) 14 is dry etched and a fine opening 18 can be formed. Next, as shown in FIG. 1(c), a shower-like electron beam 19 of 100 eV is applied to the silicon oxide film (SiO2) 1 formed in FIG.
By irradiating the GaAs substrate surface through the opening 18 of 4, the opening 1 of the silicon oxide film (SiO2) 14 is exposed.
A chemical reaction between the chlorine gas and GaAs or AlGaAs is caused by the electron beam on the surface of the GaAs substrate immediately below the surface of the substrate 8, resulting in efficient etching. The etched portion 21 formed in this way was processed using an electron beam etching device as shown in FIGS. 2(b) and 3(c) and an organometallic vapor phase epitaxy device connected via vacuum. A silicon oxide film (SiO2
) 14 as a mask during selective growth, it becomes possible to selectively grow GaAs 22 by embedding it as shown in FIG. 2(d). In this metal organic vapor phase growth, trimethyl gallium (TMC) and AsH3 are used as raw materials, and the pressure is 0.
01Torr, substrate temperature 650-770℃, total flow rate 30
I went with sccm.

In the embodiment described above, a focused electron beam is used to process the silicon oxide film (SiO2) 12, but the same process can be performed by using a focused ion beam instead. Furthermore, in processing the GaAs substrate 11, it is not always necessary to use a shower electron beam; instead, a reactive shower ion beam or a radical beam, such as chlorine reactive ion beam etching ( R.I.
A GaAs substrate may be processed by BE). However, Ga
When a shower ion beam is used to process an As substrate, a damaged layer remains on the processed surface, so the substrate temperature is 200°C.
In the above process, it is necessary to remove the damaged layer by irradiating with a chlorine radical beam or the like.

[0010]Although this example shows the crystal growth of GaAs, the present invention can be applied to other semiconductors, such as GaP and InP. However, other crystal growth methods that allow selective growth, such as chloride vapor phase epitaxy and atomic layer epitaxial growth, can also be applied. Silicon oxide film (SiO
The effects of the present invention can also be obtained by using a silicon nitride film (SiNx) instead of 2).

[0011]

According to the present invention, silicon oxide film (Si
Maskless etching can be performed in a reactive gas or radical atmosphere containing fluorine atoms by using a silicon oxide film (SiO2) or a silicon nitride film (SiNx).
SiNx) also serves as a mask for dry etching of compound semiconductors in a reactive gas or radical atmosphere containing halogen atoms. Therefore, it is possible to use this patterned silicon oxide film (SiO2) or silicon nitride film (SiNx) as a mask for both dry etching and selective implantation growth of compound semiconductors, resulting in a simple structure and accurate processing and implantation. Selective growth becomes possible.

Furthermore, since the present invention does not require wet processing using a developer accompanying photolithography of a resist mask, it can be performed in a vacuum integrated process from maskless etching to buried selective growth. It is effective in avoiding contamination from

[Brief explanation of drawings]

FIG. 1 is a sectional view illustrating the steps of a first embodiment of the present invention.

[Explanation of symbols]

11 GaAs substrate 12 AlGaAs layer 13 GaAs cap layer 14 Silicon oxide film (SiO2) 15
Filament 16 Focused electron beam 17 Zenon fluoride (XeF2) gas 18
Opening 19 Shower electron beam 20 Chlorine (Cl2) gas 21 Etched portion 22 GaAs region

Claims (3)

[Claims] [Claim 1] In a method for selectively growing a semiconductor on a III-V compound semiconductor substrate, a silicon oxide film (SiO2) is deposited on the surface of the III-V compound semiconductor substrate.
Or a step of forming a silicon nitride film (SiNx);
A step of performing maskless etching on this silicon oxide film (SiO2) or silicon nitride film (SiNx) in a reactive gas or radical atmosphere containing fluorine atoms; selectively dry etching the compound semiconductor substrate in a reactive gas or radical atmosphere containing halogen atoms using the silicon oxide film (SiO2) or silicon nitride film (SiNx) as a mask; 1. A method for selectively growing a semiconductor by selectively growing a semiconductor in an etched portion. 2. Maskless etching is a method of etching a silicon oxide (SiO2) or silicon nitride (SiO2) film using a focused energy beam such as a focused electron beam or a focused ion beam in a reactive gas or radical atmosphere containing fluorine atoms.
2. The buried selective growth method of a semiconductor according to claim 1, wherein the method is performed by irradiating the SiNx surface. 3. The dry etching according to claim 1, wherein the dry etching is performed by irradiating the surface of the III-V compound semiconductor substrate with an energy beam such as an electron beam or an ion beam in a reactive gas or radical atmosphere containing halogen atoms. Embedded selective growth method for semiconductors.