JPS5934629A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To obtain the semiconductor device, in which an excellent epitaxial growth layer is acquired, by thermally treating a substrate at a specific temperature in an oxidizing atmosphere and removing an oxide film formed to the surface of the substrate. CONSTITUTION:A wafer is divided into halves and one of them is thermally treated in an oxygen atmosphere for 1.5hr at 1,000 deg.C or more such as 1,100 deg.C, the oxide film formed is removed by hydrofluoric acid, the wafer is entered in an epitaxial growth oven, and a silicon epitaxial layer is grown in 5mum. The other is entered in the epitaxial growth oven as it is forcomparison, and an epitaxial layer is grown only by the same film thickness. Both layers are grown in an epitaxial manner through a normal method in which the surface layer of the substrate in 0.5mum is removed in a mixed gas atmosphere of HCl+H2 at 1,200 deg.C and the layer is grown at a growth rate of 1mum/min at 1,200 deg.C by using a mixed gas of SiCl4+ H2. Stacking faults are decreased and defects induced on epitaxial growth can also be reduced in the growth layer forme a in this manner. Defects difficult to be observed or defects, etc. observed as pits of shallow bottoms, shallow pits, can also be reduced remarkably.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing a semiconductor device, and particularly to a method for manufacturing a semiconductor device including an epitaxial growth layer forming step.

[Technical background of the invention and its problems J When growing an epitaxial layer on a silicon substrate,
The cleanliness of this substrate surface is very important. In such cases, a method generally used is to first lightly ablate the substrate surface with hydrogen chloride gas and then perform epitaxial growth. With this method, the stacking fault in the epitaxially grown layer is currently 1.
It is held down to about 0 pieces/d. However, there are 20 pieces/
There are many cases where cfI1 or more occurs, and it has been found that simply removing the surface layer with hydrogen chloride gas before the start of epitaxial growth is insufficient.

[Purpose of the invention]

The object of the present invention is to provide a method for manufacturing a semiconductor device that improves the epitaxial growth layer forming process and allows a high-quality epitaxial growth layer to be obtained.

[Summary of the invention]

That is, in this invention, when forming an epitaxial growth layer on the surface of a silicon substrate, the substrate is preliminarily heated to [1].
A method for manufacturing a semiconductor device 1CJ includes a step of performing heat treatment at 1000° C. or higher in a bicarbonate atmosphere and removing an oxide film formed on the surface of the substrate as a result.

In this invention, the heat treatment temperature is desirably high, and it has been found that a temperature of 1000° C. or higher improves the effect. After the heat treatment and oxide film removal step, if an epitaxially grown microorganism is then formed by a conventional method, the quality of the film can be significantly improved.

Epitaxial growth performed after heat treatment is FICl+H2
After touching the substrate surface in a mixed gas atmosphere of 8iC4+
It may be grown by the conventional method of growing with H2 mixed GUN.

[Embodiments of the invention]

Next, embodiments of this invention will be described.

The semiconductor plate used in this example is P type, with a specific resistance of 2 to 6Ω1.
silicon (100) waeno. This wafer is first cut in half. 1100 on one side according to the fourth light.
C. for 1.5 hours in an oxygen atmosphere, and after removing the formed oxide 1j with hydrofluoric acid, it is placed in an epitaxial growth furnace and a silicon epitaxial layer is grown to a thickness of 511 m. For comparison, the other layer was placed in an epitaxial growth furnace as it was, and an epitaxial layer was grown to the same thickness.

Both epitaxial growths were carried out at 1200°C using H(J-
After removing a 0.511 m substrate surface layer in a mixed gas atmosphere of 1-H, 12
A conventional method of growing at a growth rate of 1 μffi/m I n− at 00° C. is used. The density of stacking faults in the formed growth layer is measured using a microscope. Yet another 1100
After oxidation in steam for 90 minutes at °C, selective etching is performed and defects are observed again.

Table 1 compares the stacking fault density after epitaxial growth, and Table 2 compares the stacking fault density and shallow bit defect density that appeared when selective etching was performed after steam oxidation at 1100°C for 90 minutes. show. As is clear from these tables, it can be seen that according to the method of the embodiment of the present invention, defects on both the image and the surface are significantly reduced compared to the method according to the conventional example.

Table 1 Table 2 In the above examples, heat treatment was performed in an oxygen atmosphere, but other oxidizing atmospheres such as steam or a mixed atmosphere of oxygen and hydrogen chloride may be used.

In addition to epitaxial growth of silicon on a silicon substrate, for example, k1203, C
A similar effect is produced when eO2 is grown epitaxially. Furthermore, defects in the epitaxial growth layer can also be reduced for silicon substrates including a partial diffusion region used as epitaxial substrates for bipolar ICs and the like. However, in this case, use it as a diffusion mask! 4] It is important to apply this invention after removing the fallen oxide film and the oxide film formed during diffusion.

〔Effect of the invention〕

According to the invention as described above, it is possible to reduce not only the number of defects in the fine grain, but also the defects caused during epitaxial growth. For defects that are difficult to observe,
Selective etching is performed after oxidation to make it easier to observe, but stacking faults of this magnitude or defects observed as so-called shallow bits can be significantly reduced. If these various defects are left untreated, they will degrade the lifetime within the epitaxial layer or increase the leakage current of the PN junction created there; however, according to the method of the present invention, such deterioration can be prevented. , it is possible to increase the yield of various semiconductor products using epitaxial substrates.

Agent Patent Attorney Inoue - Male

Claims (1)

[Claims] Before forming an epitaxial growth layer on the surface of a silicon substrate, the substrate is heated in advance in an oxidizing atmosphere for 100 mL.
A method for manufacturing a semiconductor device, comprising a step of performing heat treatment at 0° C. or higher and removing an oxide film formed on the surface of the substrate as a result.