JPH0244714A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To reduce a defect density and to improve uniformity by ion- implanting a silicon single crystal substrate, making a surface layer amorphous, depositing an amorphous silicon film thereon, annealing it to execute its solid epitaxy, and making the amorphous layer and film of a single crystal. CONSTITUTION:The main surface of a conductivity type n-type silicon single crystal substrate 10 having 4 deg. of an OFF angle in planar orientation (100) to form an amorphous layer 11, and an amorphous silicon film 12 is deposited by a microwave plasma CVD method with monosilane as a material on the substrate. Then, it is subjected to solid epitaxy by annealing to form the layer 11 and the film 12 into a single crystal 13. Thus, a silicon epitaxial layer having less defect, good uniformity and high quality can be formed at a low temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a substrate for a silicon semiconductor integrated circuit, and particularly to a method of forming an epitaxial layer at a low temperature with excellent controllability and mass productivity.

[Conventional technology]

Conventionally, solid-phase epitaxial growth technology for silicon thin films is
Japanese Journal of Applied Physics, Volume 15, Pages 1431-1436 (1
982) (Japan, J, Appl.

Phys, 15.1431 (1982)) As discussed in Laletaire, an amorphous silicon film is deposited on a silicon single crystal substrate by a vapor phase growth method, and then the substrate is formed by annealing at 600'C or less in a conventional furnace. An amorphous silicon film is grown epitaxially with the crystal lattice of the crystal lattice oriented.

Conventionally, as a heteroepitaxial growth technique for a silicon film, as described in Japanese Patent Application Laid-Open No. 62-263627, a silicon single crystal film is deposited on an insulating film, a part of it is made amorphous, and then annealed and reused. It is crystallized.

[Problem to be solved by the invention]

In the homoepitaxial growth of the prior art described above, 0
．． The epitaxial growth is a relatively thin film of 1 to 0.3 μm, and there is no mention of a film thickness of about 1 μm, which is practical in LSI processes.

Furthermore, there is no mention of uniformity, reproducibility, or defect prevention over large areas.

On the other hand, in the conventional solid-phase epitaxial recrystallization of a heteroepitaxial layer, since the heteroepitaxial layer is essentially used as a seed crystal, there is a limit to the improvement in crystallinity of the recrystallized layer.

The purpose of the present invention is to provide a method for forming a solid phase epitaxial layer with excellent crystallinity even when the thickness is about 1 μm.

Another object of the present invention is to provide a solid-phase epitaxial growth method with low defect density, good uniformity, and good reproducibility.

[Means to solve the problem]

The above object is achieved by performing the following three steps.

1) A process of implanting ions into a silicon single crystal substrate to make the surface layer amorphous. At this time, the crystal defect density (degree of transition from single crystal to amorphous) is greatest at the surface;
It decreases as you go inside the crystal.

2) Depositing an amorphous oxide film on the substrate. The thickness of the film deposited here is the thickness of the required epitaxial layer.

3) Solid-phase epitaxial growth is performed by annealing, and the amorphous layer on the surface of the cutting plate and the deposited amorphous film are made into single crystals.

[Effect]

Defects occur when ions are implanted into a silicon single crystal substrate. The crystal defect density (the density of silicon atoms displaced by nuclear collision between the implanted ions and the silicon crystal, which becomes a complete amorphous layer when it reaches 5 x 1022an-3) is equivalent to m of the range of the implanted ions.
The amount of damage is proportional to the amount of energy lost per distance, but as the dose increases, a completely amorphous layer forms up to a point shallower than the range, and the amount of damage decreases to (li) at a depth deeper than that. .

When the surface of a substrate with such a damage distribution is cleaned and an amorphous film is deposited on it, the substrate surface and the deposited film form a continuous phase.

Annealing enables solid-phase epitaxial growth that prevents the occurrence of dislocations, stacking faults, protrusions, etc. caused by crystalline discontinuities at the interface.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

Example 1 FIG. 1(a) shows a silicon single crystal substrate 10. FIG.

The quality of the crystal is manufacturing method C72 plane orientation (1oO) off-ankle 4°, conductivity type n type, resistivity 0.01Ω (7).

1 hepant and 33 degree antimony 3.3 x 101
8a toms/i, the surface finish is super mirror finish, the diameter is 4″φ, and the thickness is 500 iLm.The off-angle surface orientation was used to prevent channeling during ion implantation.

FIG. 1(b) shows a state in which ions have been implanted into the main surface of the silicon single crystal substrate 10. Substrate 1 before ion implantation
0 cleaning involves etching with hydrochloric acid to remove the oxide film.
Prevents oxygen knock-on due to ion implantation. For ion implantation, the substrate holder was cooled to keep it below room temperature, and Ge+ ions were introduced at 100 KeV and 5X10"■-2. This resulted in a range of 600 people and a maximum of 1 degree I
oms/all was obtained, and an amorphous layer 11 was formed to a depth of about 800 nm from the surface.

FIG. 1(c) shows an amorphous silicon film 1 on the above substrate.
2 is shown deposited. Pre-cleaning of the substrate on the deposition surface involves degreasing with an organic mixture, boiling in nitric acid to form a silicon oxide film on the surface, and removing the silicon oxide film with hydrofluoric acid to expose the clean surface. In order to avoid adsorption of contamination in the atmosphere, cleaning was done with a mixture of hydrogen peroxide and ammonia water and a mixture of hydrogen peroxide and hydrochloric acid to intentionally form a silicon oxide film that is stable at room temperature but easy to remove by heating etc. . The amorphous silicon film was deposited using monosilane Si
Microwave plasma CVD using f-1,s as raw material
/i! By i. First, a vacuum container (ultimate pressure 1 x 10-
7 Torr). Flow the hydrogen and argon mixed gas to a pressure of 3 to 5 X L O-'Torr.
2,45 GHz, 600 W (7
) 7 A') Generate hydrogen/argon plasma by applying 0 waves and a magnetic field of maximum 2000 Gauss. This sputter-etches the silicon oxide film on the surface of the substrate.

Subsequently, monosilane is introduced into the vacuum container, and an amorphous silicon film is deposited on the substrate under the same conditions as above. A 1.5 μm thick film was deposited in a reaction time of 3 minutes.

At this time, the substrate temperature rose to about 160'C due to microwave and plasma irradiation.

FIG. 1(d) shows a state in which the amorphous layer and film are made into a single crystal 13 by solid phase epitaxial growth by annealing. Annealing consists of two steps: 700° C. for 30 minutes in a wet oxygen atmosphere and 800° C. for 12 minutes in a dry nitrogen atmosphere.

The epitaxial layer created in this way has a film thickness of 1.5
μm, uniformity within the wafer ±5%, impurity concentration determined by capacitance voltage method: l x I O13cm-3, resistivity 10
0Ω- mark, resistivity of 12% or less in the wafer, and stacking fault density of 5 or less in the wafer.

Embodiment 2 FIGS. 2 and 3 show an example in which the method of the present invention is applied to a bipolar LSI.

FIG. 2(a) shows a silicon single crystal substrate 2o.

The quality of the crystal is manufacturing method CZ, plane orientation (100) 4° off angle, conductivity type P type, dopant boron, resistivity 1~2
Ω-■, surface finish super mirror finished, diameter 4″φ, thickness 500 μm.

FIG. 2(b) shows a state in which a buried collector diffusion layer 21 is formed. Antimony was selectively diffused using a silicon oxide film as a mask. Antimony diffusion is carried out at 1175° in a nitrogen atmosphere using antimony trioxide 5b203 as a source.
1000°C in oxygen atmosphere after 115 minutes of deposition
, 500m, the diffusion depth is 1.1 μm, the sheet resistance is 45 to 500Ω/hole, and the thickness of the oxide film 22 on the surface is 650 and 4000.

FIG. 2(c) shows a state where ion implantation has begun after the oxide film 22 has been patterned by photolithography. The pattern of the oxide film 22 corresponds to the isolation region and has a width of 1.0 μm. The ion implantation conditions were an acceleration voltage of 150 KeV for antimony sb+, a dose of I X L O14an-2, and a substrate temperature of 30'C or less. As a result, the portion of the surface layer of the silicon substrate 20 where the silicon oxide film mask 22 is not formed becomes an amorphous layer 23.

FIG. 2(d) shows that after the silicon oxide film 22 on the substrate is removed by etching, an amorphous silicon film 2 is formed using the CVD method.
4 is shown deposited. Amorphous silicon film 24
The deposition conditions were the same as in Example 1, except that phosphine PH3 was used as a dopant to make it n-type, and the film thickness was 0.
．． It is 8 μm.

FIG. 2(e) shows the state of solid phase epitaxial growth by annealing. The annealing conditions are the same as in Example 1. At this time, the amorphous silicon film deposited on the surface of the ion-implanted area has an n-type conductivity and a resistivity of 1.
Although a single crystal film 25 of 0Ω-■ is formed, the amorphous silicon film deposited on the surface of the portion masked during ion implantation does not become a perfect single crystal but becomes a polycrystalline film 26.

FIG. 3(f) shows the state of isolation and base diffusion. The diffusion was performed using a main 1 with a 1.0 μm wide isolation opening and a 7 μm wide base opening.
- Boron B+ is ion-implanted using a resist as a mask, and drive-in diffusion is performed. Since the isolation region is made of polycrystalline silicon, the diffusion rate of boron is several times higher than that in single-crystal silicon. Therefore, by setting the boron diffusion conditions to those for forming the base layer 28, the isolation WJ2'l can be formed at the same time. In this way, photolithography and diffusion for the isolation WJ 27 and the base layer 28 can be performed simultaneously, and the process can be shortened. Furthermore, the lateral inward expansion of the isolation diffusion layer can be reduced, which can greatly contribute to increasing the drawing area.

FIG. 3(g) shows a state in which an emitter layer 29 has been formed and aluminum contacts 30a, 30b, and 30c have been further formed.

〔Effect of the invention〕

According to the present invention, a high quality silicon epitaxial layer with few defects and good uniformity can be formed at low temperature. Furthermore, it can also contribute to shortening the process and increasing precision in the semiconductor integrated circuit manufacturing process.

[Brief explanation of the drawing]

FIG. 1, FIG. 2, and FIG. 3 are schematic cross-sectional views of each step showing an embodiment of the present invention. 10.20...Silicon single crystal substrate, 11.23...
Amorphous layer, 12.24...Amorphous film, Fig. 2

Claims (1)

[Claims] 1. In forming an epitaxial layer on a single-crystal substrate, (a) forming an amorphous layer by implanting ions into the surface layer of the single-crystal substrate; (b) forming an amorphous silicon film on the substrate; A method for manufacturing a semiconductor device, comprising: (c) depositing an amorphous layer and an amorphous film into a single crystal by annealing the substrate.