JPH01183825A - Formation of single crystal silicon film - Google Patents

Abstract

PURPOSE:To improve Hall mobility, i.e., crystallizability, by annealing and treating a single crystal Si film grown by applying Si molecular beams in a hydrogen atmosphere at a temperature within a specific range. CONSTITUTION:The upper section of a single crystal substrate 1 is irradiated with silicon molecular beams and a single crystal silicon film 3 is formed, and the single crystal silicon film 3 is annealed and treated at a temperature of 700-900 deg.C in a hydrogen atmosphere. The Hall mobility of the single crystal Si film 3 shaped by applying Si molecular beams is improved through the annealing treatment, and crystailizability is enhanced. Accordingly, the single crystal Si film 3 having excellent crystallizability can be formed, inhibiting the generation of autodoping in which impurity concentration in the single crystal Si film 1 and the insulating layer changes.

Description

DETAILED DESCRIPTION OF THE INVENTION A) Field of Industrial Application The present invention relates to a method for forming a single crystal silicon film, and more particularly to a method for forming a single crystal silicon film on an insulating layer to form an SO1 structure.

) Conventional technology: Insulating @ or monocrystalline silicon (Si) on an insulating substrate
) [ is formed as S OI (Sil 1con
onInsulJor) or S OS (Sili
This structure is known as a con-on-5-apphire structure, and is known as a structure that enables higher integration and higher speed in semiconductor integrated circuits.

CVD, beam annealing, MBE, and other methods are known as methods for forming single-crystal Si films, which are important in creating SOI structures. Profile control can be performed with high precision (for example, Applied Physics
s Letters 36 (91, I May 19
80 pages 741 to 745 rGrowth of
$1hin 5ilicon films on 5a
phire and spinelg by mol
ecular beam epitaxyJ).

C) Problems to be Solved by the Invention The film quality of the single crystal Si film formed on the insulating film has a great influence on the characteristics of the semiconductor layer formed on the single crystal Si film, so it is about the same as that of the single crystal Si substrate. It is desired to improve the film quality so that it has crystallinity.

As a method to improve the crystallinity of single-crystal Si films, high temperature (1
There is an annealing treatment at a temperature of 000°C or higher).

However, if the lower insulating layer of the single crystal Si film is a sapphire substrate or a spinel (MgO, At203) film, the AL will pass from the insulating layer to the upper single crystal Si film.
There was a problem in that auto-doping occurred and the impurity concentration of the single crystal Si film and the insulating layer changed.

The present invention has been made with the above points in mind, and is intended to form a single crystal Si film with good crystallinity while suppressing the occurrence of autodoping.

2) Means for Solving the Problems The present invention provides a single-crystal Si film formed by irradiating a Si molecular beam onto a single-crystal substrate at a temperature of 700°C to 900°C in a hydrogen atmosphere.
This is a diagram showing the formation of a single crystal Si film which is annealed at a temperature of .degree.

E) Effect The above-described annealing treatment improves the hole mobility of the single crystal 5ifli formed by irradiating Si molecular beams. That is, crystallinity is improved.

f) Embodiment FIGS. 1A to 1C are process explanatory diagrams according to an embodiment of the present invention.

(1) is a single-crystal Si substrate (FIG. 1A) having a (100) plane as a main surface. The group &(1
) was grown using a vapor phase epitaxial method using At-HCL-MgC12-CO2-H2 yarn at a growth temperature of 920°C, and a single crystal spinel (MgO.At20S) [
[! ii! +21 (Figure 1B). The thickness of the spinel film (2) is 200°C. Next, this substrate is installed in an MBE apparatus (not shown), and a single crystal Si film (3) is grown epitaxially on the spinel film (2) (see Section 1).
Figure C). At this time, the growth temperature (substrate degree) was set to 800°C, and a Si molecular beam was irradiated onto the spinel film (2) so that the growth rate was about 1OA/S.
is grown to 1 μm.

The substrate on which the Si film (2) has been formed is annealed at a temperature of 800° C. for 10 minutes in a hydrogen atmosphere.

This annealing treatment improves the crystallinity of the single crystal Si film (3).

The hole mobility of a single crystal Si film without annealing treatment is 1
FIG. 2 shows the value of the hole transfer 1lFIK of a single crystal Si film annealed in a hydrogen atmosphere at different temperatures. As can be seen from FIG. 2, compared to a single crystal Si film that is not annealed in a hydrogen atmosphere, hydrogen #Fi598. The hole mobility of the single-crystal Si film that has been annealed inside is improved by about 1.4 times (Hole mobility is .

Without annealing treatment 66 a4/vsee, 8
When annealing in a hydrogen atmosphere at 00°C, 91
, 1 ai/v seC). This is thought to be due to the crystal rearrangement caused by heat and the reduction of the oxygen concentration on the Si-exchanged surface, that is, the reduction of acid-induced dendrite defects due to the condensation atmosphere.

In particular, molecular beam irradiation is performed in an ultra-high vacuum, but in order to heat the substrate, impurity gas (particularly oxygen) is generated from the substrate holder, etc., and oxygen is supplied from the underlying insulating film to cause growth. The oxygen concentration in the Si film may become crystallized. When this oxygen is removed by annealing in a hydrogen atmosphere, the crystallinity improves, thereby increasing the hole mobility.

As can be seen from FIG. 2, the hole mobility is significantly improved when the humidity of the annealing treatment is in the range of about 700° C. to 900° C. compared to the case without the annealing treatment.

Furthermore, when the annealing temperature exceeds 950°C, autodoping of ht occurs from the underlying spinel film (2), changing the impurity concentration (which is also thought to be the cause of deterioration of hole mobility); Since the annealing treatment is performed at , the occurrence of autodoping can also be suppressed.

In this embodiment, the lower layer of single crystal Si formed by Si molecular beam irradiation is a single crystal spinel film, but as long as it is a single crystal, it may be a sapphire substrate or a spinel substrate.

g) Effects of the Invention As is clear from the above description, the present invention provides a method for growing a single crystal Si film grown by irradiating Si molecular beams at 700°C to 900°C.
By annealing in a hydrogen atmosphere at a temperature of .degree. C., the hole mobility can be improved, that is, the crystallinity of the single crystal Si film can be improved. □Therefore, it is possible to form an element with different characteristics as an element on the 501 structure.

[Brief explanation of the drawing]

FIGS. 1A to 1C are process explanatory diagrams of an embodiment of the present invention, and FIG. 2 is a diagram showing the relationship between annealing temperature and hole mobility. (1)...Single crystal Si substrate, (2)...Single crystal spinel film, (3)...Single crystal Si@.

Claims (2)

[Claims] (1) A single crystal substrate is irradiated with a silicon molecular beam to form a single crystal silicon film, and the single crystal silicon film is annealed at a temperature of 700°C to 900°C in a hydrogen atmosphere. A method for forming a single crystal silicon film. (2) The method for forming a single crystal silicon film according to claim 1, wherein the single crystal substrate is an insulator.