JPS6197029A - Formation of coated film - Google Patents

Abstract

PURPOSE:To eliminate the generation of uncoupled bonds by adding heat energy or heat energy and light energy of <=300nm wavelength to a gaseous silicon fluoride contg. Si2F6, and forming a coated film consisting essentially of silicon on the surface to be coated. CONSTITUTION:Si2F6 is supplied from 11, and discharged by a vacuum pump 14 from a discharge port 7 through a pressure regulating valve 12 and a stop valve 13. Ten lamps 4 (low-voltage mercury-vapor lamp) for generating light of <=300nm wavelength and their related electric power source system 5 are used for the photochemical reaction. Some gaseous hydrogen is introduced into a lamp chamber 28 from 24 to prevent the reflux of a reactive gas, and heated to about 600 deg.C by a heater 25 to decompose a refluxed undercomposed silicon compd. The pressure in the lamp chamber 28 is equalized with the pressure in the reaction chamber 1 by regulating a valve 27 to prevent the breakage of the quartz glass 26 of the window.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to a coating mainly composed of silicon to which fluorine is added by a vapor phase reaction method using thermal and photochemical reactions (hereinafter referred to as CVD method), such as a non-single crystal semiconductor or amorphous silicon. The present invention relates to a method of manufacturing a semiconductor.

In this invention, 5i-F bond or 5i-F bond is added with fluorine.
...Has an H bond, and hydrogen is the conventionally known 5i
The present invention relates to a method for producing a film whose main component is silicon in a sufficiently smaller amount than that when produced from Ha.

This invention involves reacting 5izF4, a fluoride of silicon, with hydrogen to form a silicon coating at a temperature of 800°C or less, preferably 10°C.
It relates to a method of forming at 0 to 500°C, for example 300°C.

Conventionally, in order to produce an amorphous silicon film, 5i
A photo-CVD method using zF is known. However, such an amorphous silicon film has dangling bonds of silicon remaining in the film, and has residual hydrogen of 10 atomic % or more, so it lacks heat resistance.

Furthermore, the hydrogen for neutralizing the remaining dangling bonds is broken by a relatively strong electric field, creating dangling bonds.For example, this hydrogen forms a channel forming region in an insulated gate field effect semiconductor device. I can name semiconductors. In such a region, the electric field is concentrated at the semiconductor insulating film interface by the gate voltage method, and carriers are concentrated, resulting in 5i
When the -H bond breaks, the resulting unpaired bond constitutes an interfacial unit, causing property deterioration. For this reason, there has been a need for a terminator that has strong binding strength and neutralizes unpaired bonds.

For this purpose, the present invention aims to produce a film containing silicon as a main component by using a fluoride of silicon, particularly preferably 5izF4.

The main reaction formula is 5izFb → 2Si + 3h + 3T.

Or, SigFh+ 38z → 2Si + 6H
It is F. - Therefore, 5izF* or 5i as a fluorinated silicide gas
It is characterized by using 5inFzy++t (n≧2), particularly preferably SiJ+, represented by 3FB.

The present invention will be described below according to the drawings.

Figure 1 shows the optical CVD or thermal CVD used in the present invention.
An overview of the device is shown.

In the drawing, the reaction vessel or vacuum vessel (1) is made of stainless steel and is provided with a quartz window (26). The substrate (2) is placed on a holder (22) heated from below by a halogen heater (3), and heated to room temperature to 900°C, preferably 200 to 500°C, for example 300°C. The doping system consists of a flow meter (6) and a pulp (7), and hydrogen is supplied from (10).

Further, silicon fluoride is supplied from (11). Here, 5izF was used as the silicon fluoride.

Further, the pressure adjusting pulp (12) and the stop pulp (13) were passed through the exhaust port (7), and the mixture was evacuated from the vacuum pump (14). In order to cause a photochemical reaction, a generation lamp with a wavelength of 300 rv or less (low-pressure mercury lamp, manufactured by Ushio Inc., υL) is used.
1-45EL2-N-1) (4) and the associated power supply system (5) were used. Furthermore, this lamp chamber (28) was connected to an exhaust system and evacuated. In order to prevent the backflow of reactive gas into this lamp chamber, a small amount of hydrogen gas was introduced from (24) and heated to 600° C. with a heater (25) to decompose the backflow of undecomposed silicon compounds. In addition, the lamp chamber (2
In 8), the pressure was adjusted to be the same as that in the reaction chamber (1) using pulp (27) so as not to break the quartz glass (26) of the window. In this way, among the ultraviolet light generated at the source, it was possible to prevent the absorption loss of the short wavelength light of 184 nm, especially due to water vapor in the atmosphere, before it reaches the inside of the reaction vessel (1).

Examples are shown below.

Example 1 In this example, a semiconductor film containing silicon as a main component was prepared by a photochemical reaction between 5izFa and ammonia.

In FIG. 1, a silicon substrate (2) for forming a silicon nitride film by heating the substrate to 300° C. with a heater (3) is placed on a boat holder (2) above the heater. Furthermore, the pulp (10) was opened to introduce hydrogen. Furthermore, 5izF was introduced as 5izF*/Hz#1/1. The internal pressure of the reaction vessel was in the range of 0.1 to 100 torr, for example 10 torr. Then, silicon nitride could be obtained in the reaction tube at a growth rate of 0.7 persons/second without using mercury sensitization by photo-CVD method using irradiation with ultraviolet light of 184 nm and 254 nm. The film growth rate was reduced to 0.2 people/second when set to 3 torr.

Further investigation of the electrical properties of the formed film revealed that the dark conductivity was 3 x 10'° (0 cm)-rin, and the photo conductivity was 6 x 104.
(0cm) -'(AMI 100o+W/cm was obtained. Furthermore, the optical energy band width was 1.6 to 1.7
eV, and the optical energy band width hardly changed even when heated to 400°C.

When this reaction product was examined by IR (infrared absorption spectrum) with a thickness of 0.2 μm, large absorption was observed at 2000 cm-' and 880c+i-', and 5t-H
, it was found that SiF bonds exist. Furthermore, what is important in the method of the present invention is that when the oxygen concentration in this film was investigated by SIMS (secondary ion spectroscopy, using a 3F model manufactured by Cameca), it was found that the plasma gas phase reaction with the conventionally known 5in4 In I x 10"cm-'~
Although it contained a large concentration of oxygen of 5 X 10"cm-", in the present invention, it is less than 4XIO"cm-3, which is less than 1/10 of the conventional value.The reason is that The following can be considered: 5izF6 and H2
HF is generated as a residual gas after the reaction with. This I
P exists as an impurity and reacts with SiO□, 5iOH to form Sin, + 4HP-+SiF4+ H
2O produces water and 5iFa, which are more stable than 5izFa. As a result, since water cannot react with SiF4 again in such a state, it is presumed that the high purification action was completed at the same time as the film was formed. However, in the conventionally known decomposition reaction of silane, silane leaks at room temperature and reacts with residual oxygen and water, so it is presumed that silicon oxide and 5iOH are likely to exist in the film. .

That is, 5inFia*z (n = 2+
3+...) or a reaction between this fluoride and hydrogen to form a silicon film. However, this reaction
When eHa or GeF4 is mixed at the same time, fluorine-doped S i xGe I-x (0<X<2) can be obtained. Also WF6. It is also possible to form WSizJOSi2 by mixing it with MOC14.

In addition, BF3, which is a compound with ■ value. It is possible to form a semiconductor film mainly composed of P or N type silicon by simultaneously mixing an appropriate amount of B2H4 or a monovalent compound PH3 or AsH.

In the present invention, an excimer laser (wavelength 300 to 100 rv) is used as an irradiation source of light energy of 300 nm or less;
It goes without saying that f: may be used.

In the present invention, it is also possible to simultaneously mix mercury for excitation of a photochemical reaction and use a mercury excitation method.

However, methods using mercury bubblers tend to leave mercury in the exhaust gas, which tends to cause pollution problems.

[Brief explanation of drawings]

FIG. 1 shows an outline of an optical CVO apparatus for carrying out the method of the present invention.

Claims (1)

[Claims] 1. Creating a film mainly composed of silicon on a surface to be formed by applying thermal energy or thermal energy and light energy with a wavelength of 300 nm or less to a silicon fluoride gas containing Si_2F_6. A method for producing a film characterized by: 2. In claim 1, thermal energy or thermal energy and 30
A method for producing a film, characterized in that a silicon semiconductor film is produced on a surface to be formed by applying light energy with a wavelength of 0 nm or less.