JPH0746685B2 - Method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] Silicon On Insulat (Silicon On Insulat)
er, SOI), 3C-SiC is grown on the insulator and silicon is epitaxially grown on it.

[Industrial application field]

The present invention relates to a method for manufacturing a semiconductor device. More specifically, instead of recrystallization using laser annealing in the conventional SOI formation, an insulator (SiO ₂ film or silicon nitride film) on a silicon substrate is used. The present invention relates to a method for growing single crystal 3C-SiC (β-SiC) on (Si ₃ N ₄ film) and epitaxially growing silicon on this 3C-SiC.

[Conventional technology]

A conventional SOI forming method is shown in the sectional view of FIG. First, as shown in FIG. 3A, a SiO ₂ film 32 is formed on a silicon substrate 31.
Is formed and a polysilicon film 33 is grown thereon by, for example, a chemical vapor deposition (CVD) method, the polysilicon film 33 is irradiated with a laser beam (laser annealing), the polysilicon is melted, and recrystallized. To form a single crystal silicon region 35 in the polysilicon film 33, and a desired element is formed in the single crystal silicon region 35.

[Problems to be solved by the invention]

With the above method, a structure in which elements are laterally separated into polysilicon / single crystal silicon / polysilicon is obtained. However, it is possible to form the structure shown in FIG. It is being studied from the standpoint of improving radiation resistance and improving environmental resistance, that is, measures against radiation. for that purpose,
SiO ₂ is again formed on the polysilicon film 33 shown in FIG. 4 (b).
Is deposited, polysilicon is grown on it, and the laser annealing described above is performed to form a multi-layer structure of two layers, three layers, and the like, whereby a device excellent in vertical integration and environment resistance is obtained. Because it will be possible to make.

According to conventional methods, according to the laser annealing, the throughput is poor because small becomes laser beam Suppoto does not only re-crystallized was irradiated, the shape of the element to be formed, limited to the dimensions are added, the SiO ₂ film It is not understood unless the orientation of the single crystal silicon produced when recrystallizing the polysilicon above is completed and re-crystallizing it by stacking polysilicon in multiple layers, the flatness of each layer gradually becomes There is a problem in that the size of the single crystal silicon region is lost, the size of the single crystal silicon region becomes smaller as it goes upward in the pyramid shape, and the two-layer or three-layer structure is limited.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method of SOI formation that solves the above problems.

[Means for solving problems]

The above-mentioned problems include a step of forming an insulating film on a semiconductor off substrate, a step of growing a 3C-SiC film on the insulating film by a low pressure chemical vapor deposition method using SiHCl ₃ + H ₂ + C ₃ H ₈ type gas, And a step of epitaxially growing silicon on the 3C-SiC film by low pressure chemical vapor deposition using SiH ₄ (or Si ₂ H ₆ or Si ₃ H ₈ (trisilane) + H ₂ ) based gas. This is solved by providing a method for manufacturing a semiconductor device.

FIG. 1 is a sectional view of an embodiment of the present invention.

In the present invention, the insulating film 12 (SiO ₂
Film or silicon nitride film) on which a single crystal 3C is formed
A -SiC film 13 is grown, and silicon is epitaxially grown on this 3C-SiC to form a single crystal silicon film 14.

[Action]

The present applicant has developed a technique for forming a 3C-SiC film by a low pressure CVD method, and in the present invention, the technique is utilized to form a single crystal having only one orientation on an insulator. It forms a structurally stable 3C-SiC film, and a single crystal silicon film having the same orientation as that of the 3C-SiC film is epitaxially grown on this 3C-SiC film.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Conventionally, when a single crystal 3C-SiC (β-SiC) is grown on a Si substrate, a carbonized layer for relaxing a large difference in lattice constant is generally formed on the substrate in advance. Applicants have attempted to grow single crystal 3C-SiC without the carbonized layer.

As the Si substrate wafer, two types of substrates, a P type, a 4-inch (100) positive substrate and a (111) 4 ° -off substrate were used. An induction heating reactor was used for growth, and the substrate was placed on a SiC-coated graphite susceptor. Growth, SiHCL ₃ -C ₃
Select H ₈ -H ₂ system, the substrate temperature; 1000 ° C., the growth pressure; was performed at 200 Pa.

In the infrared absorption spectra of the SiC films grown on both substrates, a steep and large peak was observed at a wave number of 800 cm ^-1 . From this, it was found that the Si-C bond was formed. In the X-ray diffraction analysis, only the peak of 3C-SiC (111) was observed on the (111) 4 degree-off substrate, whereas on the (100) positive substrate, in addition to the (100) peak. ,
A peak of (111) was also observed. Also, (111) 4 ° -of
f Streak spots were observed in the backscattered electron diffraction image of the growth layer (3C-SiC film) on the substrate. From this, it was confirmed that the grown SiC film was a single crystal film having a slightly uneven surface.

In the grown SiC film, peeling due to differences in thermal expansion coefficient was not observed. From these results, it was found that under the above growth conditions, single crystal 3C-SiC was grown on the (111) 4 ° -off substrate.

Referring again to FIG. 1, a (SiO ₂ film + silicon nitride film) 12 is formed on a semiconductor substrate such as a silicon substrate 11 by a conventional technique.
(SiO ₂ film 1000Å, silicon nitride (Si ₃ N ₄ ) film 4000Å) is formed.

Then, by the above-mentioned low pressure CVD method, in a 1000 Pa, 200 Pa atmosphere, using a SiHCL ₃ + H ₂ + C ₃ H ₈ system gas, a 3C-SiC film 13
3C-Si, which has a single orientation by the backscattered electron diffraction method (RHEED) and can be called almost a single crystal.
The C film 13 could be made.

Next, use SiH ₄ (or Si ₂ H ₆ ) + H ₂ system gas at 800 ℃
When silicon was epitaxially grown by a low pressure CVD method at a temperature of up to 900 ° C., a single crystal silicon film 14 whose surface was almost a mirror surface was formed. As a result, it becomes possible to repeat the steps of forming the insulating film 12 again on the single crystal silicon film 14, growing 3C-SiC, and epitaxially growing silicon.

The apparatus shown in FIG. 2 was used to grow the 3C-SiC film 13, in which 21 is a quartz double tube, 22 is a coil for induction heating at 8 KHz, 23 is a graphite susceptor, and 24 is a mass flow. The controller (MFC), 25 is a vaporization controller. Using such a device, a (SiHCL ₃ + H ₂ + C ₃ H ₈ ) type gas is used as a double structure tube.
21 inner tube to heat the susceptor 23 to heat the silicon substrate
The temperature of 11 was raised and 3C-SiC was grown on the substrate 11.

n-SiC is formed on the p-type silicon substrate by the above method,
The result of investigating the current-voltage characteristics of the n-SiC / p-Si heterojunction is shown in the diagram of FIG. found.

〔The invention's effect〕

As described above, according to the present invention, a large-area single crystal silicon can be obtained, an element formed on the single crystal silicon can be designed without limiting the shape and size, the orientation can be controlled, and mass production can be performed. It is possible to stack any number of layers, which is effective.

[Brief description of drawings]

1 is a sectional view of an embodiment of the present invention, FIG. 2 is a sectional view of a 3C-SiC film growth apparatus, FIG. 3 is a diagram showing current-voltage characteristics of an n-SiC / p-Si heterojunction, and FIG. (A) And (b) is a conventional example sectional drawing. 1 and 2, 11 is a silicon substrate, 12 is (SiO ₂ film + Si ₃ N ₄ film), and 13 is 3C.
-SiC film, 14 single crystal silicon film, 21 quartz double tube, 22
Is a coil, 23 is a susceptor, 24 is a mass flow controller, and 25 is a vaporization controller.

Claims (1)

[Claims] 1. A step of forming an insulating film (12) on a semiconductor off substrate (11), by a low pressure chemical vapor deposition method using SiHCl ₃ + H ₂ + C ₃ H ₈ based gas on the insulating film (12). The step of growing the 3C-SiC film (13), and SiH ₄ (or Si ₂ H ₆ or Si ₃ H ₈ on the 3C-SiC film (13)
A method of manufacturing a semiconductor device, comprising a step of epitaxially growing silicon by a low pressure chemical vapor deposition method using a (trisilane) + H ₂ ) gas.