JPH01181512A - Vapor growth of single crystal silicon - Google Patents

Abstract

PURPOSE:To enable the vapor growth of a single crystal silicon layer with improved crystallizability at low growth temperature by performing washing and nucleation of surface of single crystal insulating material by using first and second surface treatment agents. CONSTITUTION:Before a first single crystal silicon layer 15 is subjected to hetero epitaxial forming on a single crystal insulation layer 12, constituting material of the single crystal insulation layer 12 is activated by a first surface treatment agent 14. Then, after removing the first single crystal silicon layer 15 by etching, the single crystal insulation layer 12 is activated again by a second surface treatment agent 16 before allowing a second single crystal silicon layer 17 which becomes a species crystal to be subjected to hetero epitaxial forming. It reduces heating temperature of the single crystal insulation material 12 and restricts impurities which thermally diffuse into a single crystal silicon layer 18 to allow the single crystal silicon layer 18 with improved crystallizability to be formed.

Description

[Detailed Description of the Invention] [Summary] The present invention relates to a method for vapor phase growth of single crystal silicon, particularly to a method for forming a single crystal silicon layer by heteroepitaxially growing silicon atoms on a single crystal insulator. A process of forming a single-crystal insulating layer on a semiconductor substrate, with the aim of lowering the heating temperature of the silicon, suppressing impurities thermally diffusing into the single-crystal silicon, and forming the single-crystal silicon layer with good crystallinity. a step of applying a first surface treatment agent over the entire surface of the single crystal insulating layer; and a step of heteroepitaxially forming a first single crystal silicon layer over the entire surface of the single crystal insulating layer coated with the surface treatment agent. , a step of removing the single crystal silicon layer by an etching method to expose the single crystal insulating layer, a step of applying a second surface treatment agent to the entire surface of the single crystal insulating layer, and a step of applying the surface treatment agent. a step of heteroepitaxially forming a second single-crystal silicon layer on the entire surface of the single-crystal insulating layer; and a step of forming a third single-crystal silicon layer on the entire surface of the single-crystal silicon layer. .

[Industrial application field]

The present invention relates to a method for vapor phase growth of single-crystal silicon, and more specifically, to a method for forming a single-crystal silicon layer by heteroepitaxially growing silicon atoms on a single-crystal insulator.

[Prior Art] Fig. 2 is a diagram explaining a conventional single-crystal silicon vapor phase growth method, and Fig. 2 (a) to (e) show diagrams of the vapor-phase growth process of a single-crystal silicon layer. There is.

In the figure, first, a single crystal insulator jl! is placed on a p-type or n-type Si substrate l! form 12. The single crystal insulating layer 2 is made of sapphire (81zOi), magnesia spinel (M
gO.^tWO□) or yttrium-stabilized zirconia (ZrOt-YtOs). Further, the temperature of the Si substrate 1 is maintained at about 1050° C. by the heating source 3 (FIG. 2(a)).

Next, p-type or n-type Si atoms are heteroepitaxially grown in a hydrogen (H) atmosphere by atmospheric pressure CVD or the like to form a single-crystal Si layer 4 on the Altos JI2 or the like. The crystallinity of the single crystal 5iji4 is based on the Si substrate l.
It depends on the heating temperature, and the higher the heating temperature, the better the crystallinity. However, when the heating temperature becomes high, for example, M
In the case of gO Altoz N 2, Mg and AI, and in the case of A1102 layer, AI thermally diffuses into the heteroepitaxially grown single crystal 5iJi4 to form a good single crystal S.
LJg cannot be formed (Figure (b)).

Therefore, the entire surface of the single crystal 5iJi4 is once removed by anisotropic etching such as RIE. The etching gas is CF.
Use alox. As a result, MgO・AI,O.

Mg thermally diffused into the single crystal Si layer 4 from near the interface of N2, etc.
and AI can be removed ((C) in the same figure).

Next, a surface treatment agent 5 containing a molybdenum compound is applied onto the MgO.AItos JFI2 to perform surface treatment.

The surface treatment agent 5 containing molybdenum is an aqueous solution obtained by diluting a mixed solution of molybdenum oxide (Mo01) and hydrogen peroxide (llto*) several tens of times. According to the vapor phase growth method of single crystal silicon previously patented by the present inventors (Japanese Patent Application No. 58-233118, Japanese Patent Application Laid-open No. 60-124817), the surface treatment agent 5 is
By coating a single crystal insulating layer such as
The effect of lowering the heating temperature (growth temperature of single crystal SIN) has been reported (Figure (d)).

Next, heteroepitaxial growth is performed on the entire surface of the surface-treated Sii plate 1 by atmospheric pressure CVD, etc.
Single crystal 5iJl again on zOs Ji2! form j6. In addition, single crystal SiJ! J6 becomes the silicon layer for seeding. In addition, the temperature of the heating a3 of the Si substrate 1 may be about 965°C. Also, in the enlarged diagram drawn out by the broken circle in FIG. MgO・A1201 layer 2 to single crystal 5iJi'J
These are impurities such as Mg and A1 that have thermally diffused into 6 (see figure (e)
)).

There is also a method of directly forming single crystal Si by heteroepitaxial growth without surface treatment of the Mg0-Altos layer 2 after the formation step shown in FIG.
It is necessary to maintain the heating temperature of the TG board 1 at 1050°C.

[Problem that the invention seeks to solve]

By the way, according to the conventional example, the first single crystal 5LN4, which was heteroepitaxially grown on the MgO.41.01 layer 2 at a heating temperature of 1050.degree.
It was used to clean the interface between O, N 2 and the single crystal 5ilW4, and then the heating temperature was set to 965°C, and the M g O.
The surface of Altoz 712 is treated with a surface treatment agent 5 to form a second single crystal 5iJi6.

For this reason, even though the heating temperature was lowered from 1050°C in the first heating to 965°C in the second heating, the amorphous portion 8 as shown in FIG. 2(e) and the Mg0-Alto
A thermally diffused from the s-layer 2 to the single crystal 5iJiJ6! Ya Mg
Impurities 7 such as the following are generated in the single crystal Si layer 6.

This poses a problem in that a single crystal silicon layer with good crystallinity cannot be obtained.

The present invention was created in view of the problems of the conventional example, and it lowers the heating temperature of the single crystal insulator, suppresses impurities thermally diffusing into the single crystal silicon layer, and creates a single crystal silicon layer with good crystallinity. A vapor phase growth method for single-crystal silicon that makes it possible to form .

[Means for Solving the Problems] The single-crystal silicon vapor phase growth method of the present invention includes a step of forming a single-crystal insulating layer I2 on a semiconductor substrate 11, as shown in FIG. a step of applying a first surface treatment agent 14 to the entire surface of the single crystalline KIM 12; and a step of heteroepitaxially applying a first single crystal silicon layer 15 to the entire surface of the single crystal insulating layer 12 coated with the surface treatment agent 14. a step of removing the single-crystal silicon layer 15 by etching to expose the single-crystal insulating layer 12; and applying a second surface treatment agent 16 to the entire surface of the single-crystal insulating layer 12.
a step of heteroepitaxially forming a second single crystal silicon layer 17 on the entire surface of the single crystal insulating layer 2 coated with the surface treatment agent 1G; and a step of forming a third single crystal silicon layer 17 on the entire surface of the single crystal silicon layer I7. The above-mentioned promise is achieved by forming a single crystal silicon layer 18.

[For production]

According to the present invention, before the first single-crystal silicon layer is heteroepitaxially formed on the single-crystal insulating layer, the constituent material of the single-crystal insulating layer is activated with the first surface treatment agent. For this reason, when the first single crystal silicon layer is formed heteroepitaxially, the constituent materials present on the surface of the single crystal insulating layer activated by the heating temperature lower than that in the past and the first single crystal silicon layer are
It becomes possible to replace silicon atoms in the first single crystal silicon layer to form nuclei, and to thermally diffuse surplus constituent materials into the first single crystal silicon layer.

Further, according to the present invention, after the first single crystal silicon layer is removed by etching and before the second single crystal silicon layer serving as a seed crystal is heteroepitaxially formed, the single crystal insulating layer is etched using a second surface treatment agent. Since the surface is activated again, it is possible to further reduce the heating temperature for heteroepitaxially forming the second single-crystal silicon layer compared to the heating temperature for heteroepitaxially forming the first single-crystal silicon layer. .

This makes it possible to form a single crystal silicon layer with good crystallinity.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram illustrating the vapor phase growth of a single crystal silicon layer according to an embodiment of the present invention, and the figure is a diagram illustrating the vapor phase growth process of a monocrystalline silicon layer according to an SOI structure according to an embodiment of the present invention. The figure shows.

In the figure, first, a single crystal insulating layer 12 is formed on an n-type or n-type Si substrate 11. In addition, single crystal insulation [12 is sapphire (81□03), magnesia spinel (MgO
・81g (h) or indolium stabilized zirconia (
ZrO□・Yz(h), etc., and in this example, MgO
・A1□o, i12 is used. Further, the temperature of the Si substrate 11 is maintained at approximately 965° C. by the heating source 13 (FIG. 1(a)).

Next, a first surface treatment agent 14 is applied to the Mg0-Alz (h layer 2).The first surface treatment agent 14 is an aqueous solution of a molybdenum compound.The molybdenum compound is molybdenum oxide (MoO□) This is a solution in which a mixture of hydrogen peroxide (11□0□) is dissolved in water.
4 has the effect of promoting the replacement of silicon atoms with constituent substances in the single-crystal insulating layer 12 and activating the removal of excess constituent substances on the surface of the insulating substrate 12 (FIG. 4(b)).

Next, in a hydrogen (H) atmosphere, a p-type or n-type Si layer is heteroepitaxially grown by atmospheric pressure CVD or the like to form a first single crystal 5i layer on MgO.^1ioi [12].
ji15 is formed. Note that the first single crystal Si layer 15
is used for cleaning the surface of the MgO.41201 layer 12.

Furthermore, the temperature of the heating source 13 of the Si substrate 11 is 96° C. in the embodiment of the present invention, compared to the conventional substrate temperature of 1050° C.
It can be 5°C.

As a result, Si atoms are substituted with the constituent substances of MgO・Ah (h N12, such as AI and Mg, to form nuclei, and surplus constituent substances are thermally diffused into the single crystal (5ijl15).
Same figure (C)).

Next, single crystal S
The i-layer 15 is removed to expose the MgO.^l□Ox N 12 (FIG. 4(d)).

Next, the second surface treatment agent 16 is MgO・Altos7
Apply to the entire surface of 1512. Note that the surface treatment agent 16 is a solution of a molybdenum compound or the like similar to the first surface treatment agent 14 (FIG. 2(e)).

Next, similarly to the first single crystal Si layer 15, hydrogen (11)
In an atmosphere, a p-type or n-type Si layer is heteroepitaxially grown by atmospheric pressure CVD to form hgO/AhOz.
A second single crystal Si layer 17 serving as a seed crystal is formed on the N12. Note that the temperature of the heating source 13 of the Si substrate 11 is further increased by 3.0 µm compared to the time of forming the first single crystal 5tlfi 15.
It can be reduced to 935°C, which is a 0'C reduction (see the same figure (
f)).

Next, similarly to the 1.2 single crystal 5ill15.17, Si atoms are heteroepitaxially grown by atmospheric pressure CVD to form a third single crystal Si[18] on the single crystal Si layer 17. Note that the temperature of the heating source for the Si substrate 11 at this time was 920°C. Furthermore, the single crystal Si layer 18 is used for forming elements such as bipolar transistors and MOS transistors (FIG. 2(g)).

In this way, before heteroepitaxially forming the first single crystal sil?W 15 on MgO.
The constituent materials of the first layer 12 are activated. Therefore, when forming the first single crystal 81 layer by heteroepitaxial formation, the constituent substances present on the surface of the MgO.AItoz II 12 activated by a lower heating temperature (965° C.) than in the past and the first single crystal The formation is performed by replacing the S1 atoms of the Si layer 15, or the surplus constituent material is formed into the first single crystal SIN.
This makes it possible for heat to diffuse inside.

Further, after removing the first single crystal Si layer 15 by anisotropic etching such as RIE method, a second single crystal 5 which becomes a seed crystal is etched.
The second step before heteroepitaxial formation of ill 17
The surface of the Mg0-Altos layer 12 is activated again using the surface treatment agent 16. Therefore, compared to the heating temperature (growth temperature) for heteroepitaxially forming the first single-crystal silicon, it is possible to further reduce the growth temperature (935° C.) for heteroepitaxially forming the second single-crystalline Si base layer. .

This makes it possible to form a single crystal Si layer 18 with good crystallinity at a substrate temperature of 920°C.

〔Effect of the invention〕

As explained above, according to the present invention, the surface treatment agent 1.2 and the first single crystal silicon layer clean the surface of the single crystal insulator and form nuclei.

Therefore, it is possible to grow a single crystal silicon layer with good crystallinity in a vapor phase at a low growth temperature.

This makes it possible to manufacture semiconductor devices with high density, high degree of integration, and high reliability.

[Brief explanation of the drawing]

FIG. 1 is a process diagram of a vapor phase growth process of a single crystal silicon layer according to an embodiment of the present invention, and FIG. 2 is a process diagram of a vapor phase growth process of a single crystal silicon layer according to a conventional example. 6 (Explanation of symbols) 1.11...Si substrate (semiconductor substrate), 2J12...
・MgO・A1203 layer (single crystal insulating layer), 3.13・
...Heat source, 4.6,15,17.18...Single crystal Si layer (single crystal silicon layer), 5.14.16...Surface treatment agent, 7...Amorphous portion, 8. ··impurities. 0V-13 force 51, 13 (bl Fig. 1 (2) (e) Fig. 1 (gφ3)

Claims (2)

[Claims] (1) A step of forming a single crystal insulating layer (12) on a semiconductor substrate (11), and applying a first surface treatment agent (
14), and a single crystal insulating layer (12) coated with the surface treatment agent (14).
A step of heteroepitaxially forming a first single crystal silicon layer (15) on the entire surface of the single crystal silicon layer (
15) by an etching method to expose the single crystal insulating layer (12), and applying a second surface treatment agent (
16), and a single crystal insulating layer (12) coated with the surface treatment agent (16).
A step of heteroepitaxially forming a second single crystal silicon layer (17) on the entire surface of the single crystal silicon layer (
17) A method for vapor phase growth of single crystal silicon, comprising the step of forming a third single crystal silicon layer (18) on the entire surface of the silicon layer. (2) The method for vapor phase growth of single crystal silicon according to claim 1, wherein the first and second surface treatment agents (14, 16) are aqueous solutions containing molybdenum compounds.