JPH04206932A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE:To bring an active region of an element and a gettering source close to each other for increasing a gettering effect by forming a polycrystalline silicon layer, the gettering source, and a single-crystal silicon layer, an element formation region, on the surface of one and the same silicon substrate. CONSTITUTION:A mask 2 is patterned on a silicon substrate 1 and the Ar<+> ion 3 is injected selectively to the substrate to make a region 4 an amorphous silicon layer. After removing the mask 2, silicon is made grow by CVD. In a region which has no injected ion 3, silicon grows by epitaxial growth to be a single-crystal layer 5. In the ion 3 injected region, silicon is deposited on the amorphous layer 4 and the deposited silicon becomes polycrystalline layer 6. The amorphous layer 4 recovers crystallinity in the CVD but it generates a high-density crystal defective layer 7 below the polycrystalline layer 6. By using the polycrystalline layer and single-crystal layer which are formed on the surface of one and the same substrate as a gettering source and an element active region respectively, the gettering source and the element active region can be brought close to each other and therefore a gettering effect can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor device and a method for manufacturing the same, and in particular, in a method for manufacturing a semiconductor device using a silicon substrate, a pretreatment method for a silicon substrate, which is a starting material, and a method for manufacturing a silicon substrate. This relates to the substrate structure.

[Conventional technology]

Figure 2 is an example of the monthly Sem1conductor Wo.
rld 1987, 1 (p, 88). It is a crystalline silicon film.

Next, the effect will be explained.

In the process of forming a semiconductor element on the surface of the silicon substrate 1, the strain field generated at the grain boundaries of the polycrystalline silicon film 6 deposited on the back surface of the silicon substrate 1 or the strain field due to lattice mismatch becomes a gettering source, and the semiconductor Heavy metal impurities and Na impurities introduced as a result of contamination during the manufacturing process of the device are removed and gettered from the element active region formed on the surface of the silicon substrate 1.

[Problem to be solved by the invention]

Conventional semiconductor devices are configured as described above, so
The problem is that the gettering source is located on the back surface of the silicon substrate and is far away from the active region on the front surface, resulting in a small gettering effect. Furthermore, in the manufacturing process of semiconductor devices, the polycrystalline silicon film on the back side gradually becomes thinner due to oxidation and etching, which poses a problem in the sustainability of the gettering effect.

This invention was made to solve the above-mentioned problems, and it improves the gettering effect by bringing the active region of the device and the gettering source close to each other.
The present invention aims to provide a semiconductor device and a method for manufacturing the same that can prevent a polycrystalline silicon film that is a gettering source from becoming thinner and increase the sustainability of the gettering effect.

[Means to solve the problem]

A semiconductor device according to the present invention has a polycrystalline silicon layer serving as a gettering source and a single crystal silicon layer serving as an element formation region on the same silicon substrate surface.

Further, the method for manufacturing a semiconductor device according to the present invention includes a step of selectively implanting ions into the surface of a silicon substrate to make it amorphous, and crystallizing silicon on the selectively ion-implanted surface of the substrate by a CVD method or the like. The method includes a step of growing.

[Effect]

The semiconductor device according to the present invention has a polycrystalline silicon layer and a single-crystalline silicon layer on the same substrate surface, the polycrystalline silicon layer serves as a getter link source, and the single-crystalline silicon layer serves as an element formation region. The gettering effect is improved because the source and the element formation region are close to each other, and the sustainability of the gettering effect is increased by preventing thinning of the polycrystalline silicon layer during the manufacturing process.

Further, in the method for manufacturing a semiconductor device according to the present invention, ions are selectively implanted onto a silicon substrate to form an amorphous layer, and then the same silicon as the substrate is crystal-grown on the substrate, so that the amorphous layer is formed on the silicon substrate. A polycrystalline layer serving as a getter link source is obtained as layer 2, and a single crystalline layer is obtained in the portion where ions are not implanted.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing the manufacturing process of a semiconductor device according to an embodiment of the present invention. In the figure, 1 is a silicon substrate,
2 is a mask for the silicon substrate 1'', 3 is an ion implanted selectively by the mask 2, 4 is a layer made amorphous by the implanted ions 3, and 5 is a chemical vapor deposition method (Chemical vapor deposition method).
1 is a silicon single crystal (epitaxial layer) grown by Vapor Deposition (CVD), 6 is a silicon polycrystalline layer grown by CVD, 7 is a crystal defect layer left when the amorphous layer 4 recovers the crystal, and 8 is a An oxide film for element isolation, 9 a gate electrode, 10 a source/drain region, 11 an interlayer insulating film, and 12 a wiring layer.

In FIG. 1(a), a mask 2 is patterned on a silicon substrate 1 and Ar+ ions 3 are selectively injected at 150 k
e V, I x 10 I6 atoms/ci injection. The implanted region 4 becomes amorphous. Next, as shown in FIG. 1(b), after removing the mask 2, silicon is grown to a thickness of about 500 nm at 850'C by CVD. In the region where no ion 3 is implanted, silicon grows epitaxially and becomes single crystal N5. ion 3
In the region where silicon is implanted, silicon is deposited on the amorphous layer 4, resulting in a polycrystalline layer 6. The amorphous layer 4 undergoes crystalline recovery during CVD, but a depth of 250 nm is formed under the polycrystalline layer 6.
A high-density crystal defect layer 7 is generated. Using the semiconductor substrate formed as described above, as shown in FIG. Source/drain region 10. An interlayer insulating film II, a wiring layer 12, and the like are formed and used as an active region of a semiconductor element. The polycrystalline region 6 is arranged as a region where the single crystal semiconductor substrate is not used, such as a scribe line, a wire bond pad, and a wide element isolation region.

In this example, the surface of the silicon substrate is selectively made into an amorphous layer by ion implantation, and silicon is crystal-grown on the silicon substrate, so that a polycrystalline layer is formed in the amorphous layer portion. Since a single crystal layer was formed in the other parts, both a polycrystalline layer and a single crystal layer can be obtained on the same silicon substrate surface. In addition, since the polycrystalline layer and the single crystal layer on the same substrate surface are used as a gettering source and an element active region, respectively, the gettering source and the element active region are brought close to each other, and the gettering effect can be increased.
It is possible to prevent the polycrystalline silicon film from becoming thinner during the manufacturing process and increase the sustainability of the gettering effect.

Note that in the example described above, Ar'' ion 3 is shown, but any ion species may be used as long as it does not cause any problems in terms of the performance of the semiconductor device. Also, regarding the ion implantation conditions and silicon growth conditions, single crystal Any conditions may be used as long as the region 5 and the polycrystalline region 6 are formed on the same substrate l.

Alternatively, the ions 3 may be implanted through some kind of thin film. Thereby, the state of the polycrystalline region 6 and the state of the crystal defect layer 7 can be changed.

In the above embodiment, the amorphous layer 4 was selectively formed by ion implantation using the mask 2, or it may be formed by scanning an ion beam.

Furthermore, the single crystal region 5 and the polycrystal region 6 may be formed using electrons, neutral particles, electromagnetic waves (light), solid particles, or the like.

In the above embodiment, the silicon substrate 1 was explained, but G
The present invention may be applied to other single semiconductor substrates such as e, and compound semiconductor substrates such as GaAs.

Further, if the above embodiment is used in combination with a conventional gettering method, a stronger gettering effect can be expected.

〔Effect of the invention〕

As described above, according to the present invention, the gettering source in the conventional semiconductor device was located on the back surface of the semiconductor substrate or deep inside the substrate, whereas the gettering source is located in the polycrystalline layer and crystal defects, which are the gettering sources. By forming the layer on the substrate surface and adjacent to the element formation area, the gettering effect is improved.
In the single crystal layer in which the device is formed, impurities and crystal defects that adversely affect the electrical characteristics of the device are reduced, resulting in extremely good electrical characteristics of the device. Therefore, the electrical characteristics can be significantly improved, and the yield of the device can be dramatically improved.

Further, according to the present invention, silicon is grown as a crystal after selectively implanting ions onto the surface of the silicon substrate, so that a single crystal layer that becomes an element formation region and a polycrystalline layer that becomes a gettering source are formed. This has the advantage that both can be formed on the same substrate surface.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing a manufacturing process of a semiconductor device according to an embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view showing a process of manufacturing a conventional semiconductor device. In the figure, 1 is a silicon substrate, 2 is a mask, 3 is implanted ions, 4 is an amorphous layer, 5 is a single crystal layer (epitaxial layer), 6 is a polycrystalline layer, 7 is a crystal defect layer, and 8 is element isolation oxide film, 9 is a gate electrode, IO is a source/drain region,
11 is an interlayer insulating film, and 12 is a wiring layer. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) A semiconductor device characterized by having a single crystal region serving as a semiconductor element formation region and a polycrystalline region serving as a gettering source on the same semiconductor substrate surface. (2) A method for manufacturing a semiconductor device, comprising a step of selectively amorphizing a surface layer on a semiconductor substrate, and a step of growing crystals of a semiconductor layer made of the same material as the semiconductor substrate over the entire surface of the substrate. A method for manufacturing a semiconductor device, characterized by: