JPS63137412A - Manufacture of semiconductor substrate - Google Patents

Abstract

PURPOSE:To make the crystalline property of an Si single crystal thin film excellent and to implement low defect density as a result of it, by forming an amorphous film from a first Si single crystal thin film layer by an ion implantation method, and performing a solid growing step twice at a high temperature. CONSTITUTION:An oxide single crystal thin film 2 is formed on an Si single crystal substrate 1. Then the substrate 1 is oxidized at high temperature, and a thermal oxide film 3 is formed between the substrate 1 and the film 2. Then an Si single crystal thin film 5 is formed on the film 3 by a vapor growth method. Si ions are implanted in the film 5. An amorphous Si layer 7 is formed in the vicinity of the interface between the film 2 and the film 5. Then solid growth is performed at high temperature, and the layer 7 is transformed into an Si single crystal thin film 51 having excellent low-defect density. Then Si ions are implanted into the film 51, and the amorphous Si layer 8 is formed in the vicinity of the surface of the film 51. Thereafter high temperature heat treatment is performed, and an Si single crystal thin film 52 having an excellent crystal structure is formed. When an Si single crystal thin film is formed by a homogeneous epitaxial gowing method with the film 52 as a seed crystal, a semiconductor substrate having an Si single crystal film 6 characterized by excellent crystalline property is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial application field
sulator) type substrate structure, for example, high-speed
1st year of high school! The present invention relates to a method of manufacturing a semiconductor substrate with a low defect density, on which a hybrid circuit of bipolar transistors and MOS transistors can be formed.

(0) Prior Art Conventionally, sapphire substrates have been used, for example, in SO8 technology. SO8 technology constructs MOS devices by heteroepitaxially growing a silicon thin film on a sapphire substrate, solving the conventional problems of wiring capacity and isolation between elements, and increasing the speed of MOS devices. This is what I did. Furthermore, in order to overcome the drawbacks of SO8 technology, new semiconductor substrates have been proposed in which the entire silicon substrate is coated with a spinel single crystal thin film or a stabilized zirconia thin film doped with YlCa, M(J, SC, etc.). .

Silicon single-crystal thin films formed on sapphire single-crystal substrates by vapor phase growth do not have very good surface morphology or crystallinity, and are prone to contamination due to /l autodoping, with a defect density of 103 to 10'. (pieces/cm'), and the sapphire substrate is expensive, so at present it cannot be widely used as a substrate for device production.

In view of this situation, we have developed a new semiconductor in which a silicon substrate is coated with a spinel single-crystal thin film or a stabilized zirconia thin film, and a silicon oxide film is formed at the interface between these oxide films and the silicon single-crystal substrate through high-temperature oxidation. An insulating substrate for semiconductors has been proposed, and an insulating substrate for semiconductors on which semiconductor devices can be formed has been realized.

(c) Problems to be solved by the invention However, when a silicon single crystal thin film is heteroepitaxially grown by vapor phase growth on a spinel single crystal thin film or a stabilized zirconia thin film formed on a silicon single crystal substrate, However, due to differences in lattice mismatch and thermal expansion coefficient, crystallinity deteriorated, resulting in an increase in defect density and deterioration in surface morphology.

This invention was made in view of the above circumstances, and includes a spinel single crystal thin film formed on a silicon single crystal substrate,
Forming a silicon single-crystal thin film on a stabilized zirconia single-crystal thin film using a vapor phase growth method. This method improves the drawbacks such as increased defect density and deterioration of surface morphology, which are problems in heteroepitaxial growth, and forms a silicon single-crystal thin film. To provide a method for manufacturing a semiconductor substrate having a silicon single crystal film having excellent crystallinity at a higher temperature and without contamination due to 1.12 autodoping as in the case of a sapphire substrate during vapor phase growth. The purpose is

(d) Means for solving the problem The method for manufacturing a semiconductor substrate of the present invention includes a step of forming an oxide single crystal thin film on the entire surface of a silicon single crystal substrate, and then oxidizing the silicon single crystal substrate by high temperature oxidation. A process of forming a thermal oxide film at the interface with the oxide single crystal thin film, a process of forming a silicon thin film on the oxide single crystal thin film by vapor phase growth, and an ion implantation process near the interface between the silicon thin film and the oxide single crystal thin film. The first step is to form an amorphous silicon layer at the interface between the silicon thin film and the oxide single-crystal thin film by ion-implanting silicon using a method, and then to perform solid-phase growth by performing high-temperature heat treatment. The structure includes a step of ion-implanting to form an amorphous silicon layer on the surface of a silicon thin film, and then a step of performing solid phase growth by performing high-temperature heat treatment.

The silicon single crystal substrate used in this invention is (10
0) or (111) orientation is used.

As the oxide single crystal thin film formed on these silicon single crystal substrates, a spinel single crystal thin film or a stabilized zirconia single crystal thin film having the same orientation as the silicon single crystal substrate is used, and the film thickness is 300 ~ The thickness is preferably about 1 μm.

The above-mentioned oxide single crystal thin film may be made of, for example, 10
Hydrogen (H2) gas and 0.1
It is preferable to clean the surface by gas etching, for example 50 to 1000 people, in hydrogen gas containing ~1.0% hydrochloric acid (HCI).

The thickness of the silicon single crystal thin film formed on the oxide single crystal thin film by vapor phase epitaxy is preferably about 0.02 to 1.0 μm. , Si HCI s
, 0.05 silane-based gas such as Si Cl 4
The growth rate is 0.1 to 0.1 at a temperature of 900 to 1150 °C, using hydrogen contained in hydrogen gas at a ratio of 5% to 5% by volume.
3.0. czm/min. If necessary, pyrooxidation, hydrochloric acid oxidation,
Or with dry oxygen, for example 800℃~1000℃
It is preferable to form a thermal oxide film with a thickness of 200 to 2000 at a temperature of .degree.

The ion implantation conditions for forming an amorphous silicon layer at the interface between silicon 1ill and oxide single crystal vary depending on the thickness of the silicon thin film, but for example, implantation energy is 20KeV to 400KeV, implantation amount is 1X10
It is preferable to form an amorphous silicon layer in the vicinity of the interface between the silicon thin film and the oxide single crystal thin film to a layer thickness of about 350 to 4,500 layers by forming the amorphous silicon layer in the vicinity of the interface between the silicon thin film and the oxide single crystal thin film.

When performing solid phase growth by performing high temperature heat treatment, it is preferable to perform the solid phase growth at a temperature of about 500° C. to 1150° C. for 30 minutes to 12 hours, for example, in a hydrogen or nitrogen atmosphere.

The ion implantation conditions for forming an amorphous silicon layer on the surface of a silicon thin film are, for example, implantation energy of 20
Kev~80KeV1 injection 1xlO"cr'~6x
The thickness of the amorphous silicon layer is approximately 10" cm, and the amorphous silicon layer is formed on the surface of the silicon thin film.
The number of participants will be approximately 200 people.

(e) Effect In the method for manufacturing a semiconductor substrate according to the present invention described above, an oxide single crystal thin film such as a spinel single crystal thin film or a stabilized zirconia single crystal thin film formed on a silicon single crystal substrate is oxidized at high temperature. do.

At the interface between the silicon single crystal substrate and the oxide single crystal thin film, S!
The first layer silicon single crystal thin film formed by vapor phase growth on the semiconductor substrate on which 02 was formed is made amorphous by ion implantation, and then the process of solid phase growth using aKW is performed twice. Perform double solid phase growth.

According to this method, the book value of the first layer, for example, 0.02
~1.0 μm thick silicon single crystal film and this silicon single crystal N! ! The defect density of the silicon single crystal thin film formed on the top is reduced to within 5/cn+2, and the surface morphology is also improved, so bipolar transistors and M
It becomes possible to easily create active elements such as OS transistors.

(f) Examples Examples of the present invention will be described below with reference to the drawings, but the invention is not limited to the following examples.

Example 1 FIG. 1 is a manufacturing process diagram for explaining an example of the method for manufacturing a semiconductor substrate of the present invention.

First, as shown in (ω) in FIG. 1, a spinel single crystal thin film having a (100) plane and a stabilized zirconia single crystal having a (100) plane are deposited on a silicon single crystal substrate 1 having a (100) plane. An oxide single-crystal thin film 2 like a thin film is formed to a thickness of 4500 nm.Next, this substrate is oxidized in an oxygen atmosphere at 1100°C, and as shown in FIG. A thermal oxide film (Si 02 ) 3 is formed at the interface between the single crystal substrate 1 and the oxide single crystal film 2. Next, in the epitaxial chamber, the oxide single crystal lI2 is
The surfaces of 200 people were cleaned by gas etching in hydrogen gas and hydrogen gas containing 0.3% hydrochloric acid at a temperature of 100°C. Then, add 0.2 silane (Sf H4) gas
The silane gas is contained in hydrogen gas at a ratio of % by volume and thermally decomposed at a temperature of 1000°C, and as shown in FIG. Form to a thick film.

Next, as shown in FIG. 1(d), silicon ions are implanted into the silicon single crystal thin film 5 to form an amorphous silicon layer 7 near the interface between the oxide single crystal thin film 2 and the silicon single crystal thin film 5. Form. The injection condition is injection energy 3.
An amorphous silicon layer 7 is formed in the vicinity of the interface between the oxide single crystal thin film 2 and the silicon single crystal thin film 5 in an area of 3000 m by using an injection port of 00 KeV and an injection port of 5 x 1 Q r''; cm -2. , as shown in +e) of Figure 1, in a hydrogen or nitrogen atmosphere, the single crystal silicon at the interface between the silicon single crystal thin film 5 and the amorphous silicon layer 7 is used as a seed crystal and solidified at a temperature of 1000°C for 1 hour. Phase growth is performed to modify the amorphous silicon layer 7 into a silicon single crystal thin film 51 of high quality and low defect density.That is, by performing solid phase growth by performing high temperature heat treatment, the silicon single crystal source y15 and the oxide are While correcting the lattice mismatch at the interface with the single-crystal film 2, solid-phase growth is performed using the silicon on the surface of the silicon single crystal till!5, which has excellent crystallinity, as a seed crystal. A silicon single-crystalline thin film Wi, 51 with good interfacial crystal structure and crystallinity is formed.

Next, as shown at +f+ in FIG. 1, silicon ions are implanted into the silicon single crystal thin film 51 to form an amorphous silicon layer 8 near the surface of the silicon single crystal thin film 51. Silicon ion implantation with implantation energy of 40K
The test is carried out under the conditions of eV, u input fjk 2x 1016 cr'. As a result, an amorphous silicon layer 8 is formed on the surface of the silicon single crystal thin layer 51 in a region having a layer thickness of 500 Å.

Next, as shown in (9) in the N1 diagram, the silicon single crystal thin film 51 is kept in a hydrogen or nitrogen atmosphere at 800° C. for 1 hour, and the portion in contact with the amorphous silicon layer 8 modified by the first solid phase growth is grown. A silicon single crystal thin film 52 with a thickness of 0.7 μm and a good crystal structure at an interface with excellent crystallinity is formed by growing a silicon single crystal in the surface direction using as a seed crystal, and is provided as a semiconductor substrate. be done.

When providing a semiconductor substrate with a film thickness of approximately 0.7 μm or more, the silicon single crystal thin film 52 is coated with N2 or N2.
After gas etching with 2 +HC1, aij! (for example, 900 to 1150°C) by vapor phase growth to a predetermined film thickness (for example, 0.5 to
When a silicon single crystal thin film of 20 μl) is formed by homoepitaxial growth using the silicon single crystal film 52 as a seed crystal, a low defect density (
For example, it is possible to provide a semiconductor substrate having a silicon single crystal film 6 with good surface morphology at 5 pieces/cm'').

! 1''L and (ω to fh) in FIG. The difference is the second
As shown in (C) of the figure, on the silicon single crystal thin film 5, 8
Thermal oxide film 4 in a steam (N20) atmosphere at a temperature of 50°C
is formed to a thickness of 1000 nm, and the subsequent ion implantation process is performed through this thermal oxide film 4. (small and (
t), the thermal oxide film 4 is replaced with a silicon single crystal thin film 5.
By forming and implanting ions on the silicon substrate, it is possible to prevent silicon ions from channeling in the silicon substrate, and also to prevent contamination due to fecal permeation. ) can be made smaller. Furthermore, it is possible to form an amorphous silicon layer closer to the surface of the silicon thin film. For example, if the amorphous silicon layer 8 is formed in accordance with (h) in FIG. The crystallinity of the silicon surface is increased by solid-phase growth through high-temperature heat treatment.
This is advantageous when epitaxially growing silicon in stages.

According to the above-described practical example of the present invention, a silicon single crystal thin film 6 with very good crystallinity can be obtained, making it possible to produce a semiconductor substrate free of internal stress and free from plastic deformation due to heat.

(G) Effects of the Invention As described above, according to the present invention, it is possible to form an oxide single crystal thin film such as a spinel single crystal Si or a stabilized zirconia single crystal thin film formed on a silicon single crystal substrate, which has been extremely difficult in the past. The crystallinity of the formed silicon single crystal thin film is improved, and as a result, a low defect density can be achieved, and the surface morphology can be significantly improved. In addition, since each amorphous silicon region formed within a silicon single crystal thin film is formed by ion implantation, there is little variation within the substrate plane and between substrates, and it is easy to increase the area. can be manufactured.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a semiconductor substrate sequentially showing the manufacturing process of one embodiment of the present invention, and FIG. N2 is a schematic cross-sectional view of a semiconductor substrate sequentially showing the manufacturing process of another embodiment of the present invention. It is a diagram. 1... Silicon single crystal substrate, 2... Oxide single crystal film, 3.4... Thermal oxide film (StO2), 5.6...
... Silicon single crystal thin film, 7.8 ... Amorphous silicon region, 51.52 ... Modified silicon single crystal thin film. Figure 1 Figure 2

Claims (1)

[Claims] 1. A step of forming an oxide single crystal thin film on the entire surface of a silicon single crystal substrate, a step of forming a thermal oxide film at the interface between the silicon single crystal substrate and the oxide crystal thin film by high temperature oxidation, and A process of forming a silicon thin film on a crystalline thin film by a vapor phase growth method, and a step of implanting silicon ions near the interface between the silicon thin film and an oxide single crystal thin film by an ion implantation method to form a silicon thin film and an oxide single crystal thin film. A step of forming an amorphous silicon layer at the interface, a step of performing solid phase growth by performing high-temperature heat treatment after that, and a step of implanting silicon ions near the surface of the silicon thin film to form an amorphous silicon layer on the surface of the silicon thin film. A method for manufacturing a semiconductor substrate, comprising the steps of: , and then performing a high-temperature heat treatment to cause solid phase growth.