JPS62263627A - Manufacture of substrate for semiconductor - Google Patents

Abstract

PURPOSE:To realize low defect density by improving the crystallizability of an silicon single crystal thin-film formed onto an oxide single crystal thin-film such as a spinel single crystal thin-film and a stabilized zirconium single crystal thin-film shaped onto a sapphire single crystal substrate which has been difficult to be manufactured extremely. CONSTITUTION:An oxide single crystal thin-film 2 is formed onto a sapphire (alpha-Al2O3) single crystal substrate 1, an silicon single crystal thin-film 3 is shaped onto the thin-film 2, and an amorphous silicon layer 4 is formed near the interface of the oxide single crystal thin-film 2 and the silicon single crystal thin-film 3. Solid growth is conducted, using single crystal silicon on the interface of the silicon single crystal thin-film 3 and the amorphous silicon layer 4 as a seed crystal in a hydrogen or nitrogen atmosphere, the amorphous silicon layer 4 is improved into an excellent silicon single crystal thin-film 31 having low defect density, and an amorphous silicon layer 5 is shaped. An silicon single crystal is grown in the surface direction, employing the silicon single crystal thin-film 31 in a section being in contact with the amorphous silicon layer 5 as a seed crystal, thus forming an silicon single crystal thin-film 32.

Description

[Detailed description of the invention] <Industrial application field> The present invention is directed to SO1 (silicon on 1 nsul)
This article B relates to a method for manufacturing a semiconductor substrate with a low defect density that has a ator) type substrate structure and can form, for example, a high-speed, highly integrated hybrid circuit of a Vizera transistor and a λi○S transistor. .

<Prior Art> Conventionally, sapphire substrates have been used as insulating substrates for semiconductors in place of silicon substrates, for example in SOS technology. SOS technology constructs MOS devices by epitaxially growing a silicon thin film on a sapphire substrate, solving the conventional problems of wiring capacitance and isolation between elements, and increasing the speed of MOS devices. It is. Furthermore, in order to overcome the drawbacks of SO8 technology, spinel single crystal thin films, Y,
A new semiconductor insulating substrate coated with a stabilized zirconia thin film doped with Ca, Mg, Sc, etc. has also been proposed.

Silicon single-crystal thin films formed on sapphire single-crystal substrates by vapor phase growth have poor surface morphology and crystallinity, are easily contaminated by At autodoping, and have a defect density of 109 to 1011. /crn2), and therefore cannot be widely used as a substrate for device production.

In view of this situation, a new insulating substrate for semiconductors has been proposed, which is made by coating a spinel single crystal thin film or a stabilized zirconia thin film on a S7F substrate, and is an insulating substrate for semiconductors that does not affect the characteristics of semiconductor devices. has been realized.

<Problems to be solved by the invention> However, when a silicon single crystal thin film is heteroepitaxially grown on a spinel single crystal thin film formed on a sapphire single crystal substrate or a stabilized zirconia single crystal thin film by a vapor phase growth method, However, due to lattice mismatch and differences in thermal expansion coefficients, crystallinity deteriorates, resulting in increased defect density and deterioration of surface morphology.

The present invention was devised in view of the above points, and is a method of forming a silicon single crystal thin film by vapor phase growth on a spinel single crystal thin film formed on a sapphire single crystal substrate or a stabilized zirconia single crystal thin film. In the heteroepitaxial growth process, problems such as an increase in defect density and deterioration of surface morphology are improved, and the auto-kt of the silicon single crystal thin film from the sapphire substrate, which occurs during vapor phase growth to form a silicon single crystal thin film, is improved. The object of this invention is to provide a method for manufacturing a semiconductor substrate that prevents contamination due to doping.

Means for Solving the Problems> In order to achieve the above object, the method for manufacturing a semiconductor substrate of the present invention includes forming an oxidized spinel single crystal thin film, a stabilized zirconia single crystal thin film, etc. on the entire surface of a sapphire single crystal substrate. A step of forming a silicon thin film on the oxide single crystal thin film by a vapor phase growth method, and a step of forming a silicon thin film near the interface between the silicon thin film and the oxide single crystal thin film by an ion implantation method. A step of ion-implanting to form an amorphous silicon layer at the interface between the silicon thin film and the oxide 2 single crystal thin film, followed by a step of high-temperature heat treatment to grow the same phase, and a step of forming an amorphous silicon layer near the surface of the silicon thin film. a step of ion-implanting to form an amorphous silicon layer on the surface of the silicon thin film;
After that, the structure includes a step of performing a high-temperature heat treatment to cause solid phase growth.

Further, as an embodiment of the present invention, the amorphous silicon layer on the surface of the silicon thin film is grown in a solid phase by performing the above-described high-temperature heat treatment, and is further grown to a predetermined thickness by vapor phase growth on the silicon single crystal thin film. The method is configured to include a step of forming a silicon single crystal thin film.

Effects> 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 S7F single crystal substrate is After preventing At autodoping from the sapphire substrate and making the first silicon single-crystal thin film amorphous by ion implantation, the process of solid-phase growth at high temperatures is performed twice, so-called double solid-phase growth. Do this.

According to my opinion, the thickness of the first layer is, for example, 0.02~1.
The defect density of a silicon single crystal thin film with a thickness of 0 μm and a silicon single crystal thin film formed on this silicon single crystal thin film is ~
5 (pieces/α2) and the surface morphology is also improved, making it possible to easily create active elements such as bigolar transistors and MoS transistors within the same substrate.

<Embodiments of the invention> As a sapphire single crystal substrate used in the present invention, (+10
2) or (0001) orientation is used. As the oxide single crystal thin film formed on this sapphire single crystal substrate, spinel single crystal thin films having (III) planes and (
A stabilized zirconia single crystal thin film having an Ill) plane is used, and the film thickness is preferably about +ooX to 3 μm.

The above-mentioned oxide single crystal thin film may be made of, for example, 100
Hydrogen (H2) gas or 01 at a temperature of 0°C-1 + 50°C
It is preferable to clean the surface using a hydrogen gas atmosphere containing 1% to 1% hydrochloric acid (HC2).

The thickness of the silicon single crystal thin film formed by vapor phase growth on the above-mentioned oxide single crystal thin film is preferably about 0.02 to 1.0 μm. S iHCZ
0.05vol of silane gas such as 3+5ict4
% to 1.5vo1% in hydrogen gas and thermally decompose the silane gas at a temperature of 900°C to 1200°C to achieve a growth rate of 0.05! Am/min
It is preferable to form at -3.0 μm/min.

If necessary, the silicon single crystal thin film may be heated to 800° by pyrooxidation, hydrochloric acid oxidation, or dry oxygen.
Film thickness 200~200 OA at temperature of C-1000"C
It is preferable to form a thermal oxide film of about

Ion implantation conditions for forming an amorphous silicon layer at the interface between a silicon thin film and an oxide single crystal thin film vary depending on the thickness of the silicon thin film, but for example, the implantation energy is 20 keV to 400 keV.

The implantation amount is preferably about 5.times.10@14 crn@-2 to 5.times.10@+ am@-2, and an amorphous silicon layer is preferably formed near the interface between the silicon thin film and the oxide single crystal thin film.

When solid-phase growth is performed by high-temperature heat treatment, it is preferably carried out at a temperature of about 500° C. to 1200° C. for a period of about 10 minutes to about 12 hours in a hydrogen or nitrogen atmosphere, for example.

When forming an IC amorphous silicon layer on the surface of a silicon thin film, the ion implantation conditions are, for example, implantation energy 2.
0 keV -200keV, implantation dose 5XI Q"
It is preferable to carry out the injection at about 2-5X IQ" cm-2, and the implantation energy is 20 keV -80 ke.
V degree, injection amount I X I O'5cm-2-5X
10"Cfn-2 is more preferable, and an amorphous silicon layer of 35OA-12 is formed on the surface of the silicon thin film.
It is preferable to form the layer to a thickness of about 0OA.

<Examples> Examples of the method for manufacturing a semiconductor substrate according to the present invention will be described below with reference to the accompanying drawings, but the present invention is not limited to these examples.

! 1(a) to 1(g) are manufacturing process diagrams for explaining one embodiment of the method for manufacturing a semiconductor substrate of the present invention.

First, as shown in FIG. 1(a) K, a sapphire (α-At203) single crystal substrate with a (+102) plane! Spinel single crystal thin film with (Ill) plane on top or (Ill)
An oxide single-crystal thin film such as a stabilized zirconia single-crystal thin film having a surface is formed to a thickness of 2 tl-4500 Å.

Next, the oxide single crystal thin film 2 was deposited at a temperature of 1100°C in a hydrogen gas atmosphere containing hydrogen gas or 0.3% hydrochloric acid at 50 OA.
Clean the surface by gas etching.

Thereafter, silane (SiH4) gas was included in the hydrogen gas at a ratio of 0.2 vol. 1%, and the silane gas was thermally decomposed at a temperature of 1000°C, resulting in an oxide single crystal thin film 2 as shown in FIG. A silicon single crystal thin film 3 is formed thereon to a thickness of 1.0 μm at a growth rate of 0.2 μm/min.

Next, as shown in FIG. 1(c), silicon ions are implanted into the silicon single crystal thin film 3 to form an amorphous silicon layer 4 near the interface between the oxide single crystal thin film 2 and the silicon single crystal thin film 3. The injection conditions are injection energy 400
The amorphous silicon layer 4 was implanted at 400 OA near the interface between the oxide single crystal thin film 2 and the silicon single crystal thin film 3 by implantation at keV and implantation dose of 5 X I Ol5 crn-2.
Form within the range of .

Next, as shown in FIG. 1(d), the single crystal silicon at the interface between the silicon single crystal thin film 3 and the amorphous silicon layer 4 was used as a seed crystal in a hydrogen or nitrogen atmosphere and solidified at a temperature of 1000°C for 1 hour. Phase growth is performed to convert the amorphous silicon layer 4 into a high quality silicon single crystal thin film 3 with low defect density.
Modified to 1. In other words, by performing solid-phase growth through high-temperature heat treatment, the lattice mismatch can be corrected at the interface between a silicon single crystal thin film, a spinel single crystal thin film, or a stabilized zirconia single crystal thin film, while improving crystallinity. Solid phase growth is performed using the silicon on the surface of the silicon single crystal thin film as a seed crystal, and as a result, a silicon single crystal thin film 31 with good interfacial crystal structure and crystallinity is formed.

Next, as shown in FIG. 1(e), a silicon single crystal thin film 3
1, silicon ions are implanted to form an amorphous silicon layer 5 near the surface of the silicon single crystal thin film 3I. That is, silicon ion implantation was performed at an implantation energy of 40
key, the implantation amount is 2.times.I O"crn-2. As a result, an amorphous silicon layer 5 is formed on the surface of the silicon single crystal thin film 31 in a region having a layer thickness of 500 Å.

Next, as shown in FIG. 1(f), the silicon single crystal is kept in a hydrogen or nitrogen atmosphere at 1000°C for 1 hour to form a silicon single crystal in the portion in contact with the amorphous silicon layer 5 that has been modified by the first solid phase growth. By using the thin film 31 as a seed crystal to grow a silicon single crystal in the surface direction, as shown in FIG. is formed and can be provided as a semiconductor substrate. Furthermore, when providing a semiconductor substrate with a film thickness of 1 μm or more, this silicon single crystal thin film 3
2 is etched with H2 or H2 + HC4, and then deposited to a predetermined film thickness (for example, 1 to 20μ
When the silicon single-crystal thin film 32 is formed by homoepitaxial growth using the silicon single-crystal thin film 32 as a seed crystal, it can be formed on an insulating substrate with good crystallinity and low defect density (for example ~5(ke, / It is possible to provide a semiconductor substrate having a silicon single-crystal thin film 6 with a good surface morphology (cm2)).

Figures 2(a) to 2(g) are manufacturing process diagrams for explaining other embodiments of the method for manufacturing a semiconductor substrate of the present invention, respectively. The difference from Figure 2 (
As shown in b), the silicon single crystal thin film 3 is heated at 850°C.
The thermal oxide film 13 is formed in a steam (H2O) atmosphere at a temperature of
．． The film is formed to a thickness of 000 A, and the subsequent ion implantation process is performed using this thermal oxidation! This is done via +3.

By forming a thermal oxide film 13 on the silicon single crystal thin film 3 and implanting ions as shown in FIGS. 2(c) and 2(e), channeling of silicon ions in the silicon substrate can be prevented. Variations between wafers due to manufacturing (
The width of the amorphous region can be reduced. In addition, it is possible to form an amorphous silicon layer closer to the surface of the silicon thin film. For example, when the amorphous silicon layer 5 is formed in accordance with FIG. The solid phase growth by heat treatment improves the crystallinity of the silicon surface, which is advantageous when epitaxially growing silicon in two stages.

According to the embodiments of the present invention described above, a silicon single crystal thin film 6 with very good crystallinity can be obtained, making it possible to create a semiconductor substrate without plastic deformation due to heat.

<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 thin film or a stabilized zirconium single crystal thin film formed on a 7-fire single crystal substrate, which has been extremely difficult in the past. The crystallinity of the silicon single crystal thin film formed on is improved,
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 between boards, and large areas can be easily manufactured.

[Brief explanation of drawings]

Figures 1(a) to (-) are schematic cross-sectional views sequentially showing the manufacturing process of an embodiment of the present invention, and Figure 2(a)
7(g) to (g)tri are schematic cross-sectional views sequentially showing manufacturing steps of other embodiments of the present invention. 1... Sapphire single crystal substrate, 2... Oxide single crystal thin film (spinel thin film or stabilized zirconia thin film), 3
...Silicon single crystal thin film, 4, s...Amorphous silicon region, 32...Modified silicon single crystal thin film. Agent Patent Attorney Takeshi Sugiyama (and 1 other person) Figure 1 (a) Figure 21 (g)

Claims (1)

[Claims] 1. A step of forming an oxide single crystal thin film on the entire surface of a sapphire single crystal substrate, a step of forming a silicon thin film on the oxide single crystal thin film by vapor phase growth, and the silicon thin film. A process of implanting silicon ions near the interface between the silicon thin film and the oxide single crystal thin film using an ion implantation method to form an amorphous silicon layer at the interface between the silicon thin film and the oxide single crystal thin film, and then performing high-temperature heat treatment to form a solid phase. further comprising the steps of: ion-implanting silicon into the vicinity of the surface of the silicon thin film to form an amorphous silicon layer on the surface of the silicon thin film; and then performing high-temperature heat treatment to achieve solid phase growth. A method for manufacturing a semiconductor substrate, characterized in that: 2. Further forming a silicon single crystal thin film of a predetermined thickness by a vapor phase growth method on the silicon single crystal thin film in which the amorphous silicon layer on the surface portion of the silicon thin film is grown in solid phase by performing the high temperature heat treatment. A method of manufacturing a semiconductor substrate according to claim 1, characterized in that: 3. The method of manufacturing a semiconductor substrate according to claim 1, wherein the silicon ion implantation is performed through a thermal oxide film formed on the silicon thin film.