JPS5989410A - Vapor phase reaction method - Google Patents

Abstract

PURPOSE:To prevent undesiable inclusion of oxide or hydroxide, by mixing fluorine or hydrogen fluoride into silane having oxygen or oxide mixed therein, and carrying out a thermochemical or plasma chemical reaction. CONSTITUTION:A plurality of pairs of substrates 1 are retained by a holder 19 and disposed in a reaction furnace 2 such as to be parallel to the flow of a reactive gas. After the furnace 2 is evacuated, silane having fluorine mixed therein is introduced into the furnace 2, and thermal or electrical energy is supplied by means of infrared heaters 7, 9 or a high-frequency power source 4, thereby to cause a thermochemical or plasma chemical reaction. If silane has oxygen or oxide mixed therein, silicon oxide or sulicon hydroxide is mixed in a silicon semiconductor film grown on the substrates 1 by the chemical reaction, causing electrical properties thereof to be deteriorated. Therefore, silane is dehydrated or deoxidized by mixing fluorine or hydrogen fluoride therein.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves adding fluorine or hydrogen fluoride to silane mixed with 1 mole or less of oxygen or oxide in an amount of 0.00% relative to the silane.
It is intended to be a reactive gas mixed at a temperature of 1 to 20%, preferably 1 to 10 degrees.

In this invention, silane mixed with such fluorine or hydrogen fluoride (hereinafter simply referred to as fluorine) is produced using a plasma vapor phase method.
It is an object of the present invention to form a non-single-crystalline semiconductor film on a surface of a substrate by using PCVD (referred to as PCVD) or reduced-pressure vapor phase method (referred to as PCVD). Non-single crystallography in which 11C1, IQ silicon oxide (S10□Generally, Siq) is mixed into such a semiconductor, and its electrical conductivity increases. and 5i-O
Electrical conduction with H-bonds mixed in! (2) By preventing the deterioration of characteristics, the purpose is to form a semiconductor that has high electrical conductivity and is not accompanied by deterioration of characteristics.

Conventionally, in the gas phase method (P (collectively referred to as 3V D or LPOVD method)), there were problems such as leakage of a very small amount of oxygen from the reactor b° into the reactor, water adhering to the inner walls of stainless steel, etc. Due to the generation of silicon oxide due to the reaction with oxygen and the incorporation of such silicon oxide into the single-layer semiconductor film, its electrical properties were not satisfactory.

In addition, when filling silane into a high-pressure container (also called a cylinder), silicon oxide is generated in the cylinder due to the adsorbed water that remains in the cylinder at the initial stage, and the ultrafine silicon oxide powder remaining in this cylinder also becomes silane. and fly inside the reactor with
Silicone and a half 4′! He was creating oxides or hydroxides in his body. In general, 10 to 3X10 am of f2 elements are mixed into the semi-decayed body of f1 and hydroxide, resulting in 'C061 to 2%.
The humidity level of Takumi Natsu was stored away. Furthermore, the conduction is not sufficient and the above-mentioned equipment? (7.) Due to leakage, more oxygen was mixed into the silicon semi-N body.

The object of the present invention is to eliminate oxygen, which is the main cause of such property deterioration and deterioration.

Therefore, the main issue is 1. ! Fluorine or pure hydrogen is mixed into silane (monosilane of 81H, or polysilane of 5inH, -Ln>2), and the fluorine dehydrates the disilane, resulting in a reaction product. 1 is characterized by removing silicon oxide or silicon hydroxide represented by KSiOx or 5i (OHλ) in non-mono-crystalline silicon.

That is, while the electric 411 degrees of oxygen is 3.0, it is 11 degrees, which is 3.5 degrees. The purpose is to carry out a dehydration reaction (which may be changed to a de-rK reaction) by adding and depleting fluorine having a gas Pi of 41 degrees.

Examples are shown below according to the drawings.

Example 1 FIG. 1 shows the (°; L) of the PCVD apparatus used in the present invention.

The substrate (1) whose surface to be formed is a) on the [,41 plane is 2
′! The reactor (2) is equipped with an infrared heater (2) in the upper and lower parts. 7) (9), which heats the substrate (1).The reactive gas flows from the blowout port (3) to the bottom of the substrate surface from above the exhaust port (8) K, and the reactive gas flows into the space near the substrate. A non-single-crystal semiconductor film is formed on the surface to be formed by converting the reactive gas into plasma in the reactor. The holder is placed in the preliminary chamber (10), and the pulp (c) is evacuated using a vacuum pump, and then introduced into the reactor by opening the gate valve.

The doping system) also includes a flowmeter α'L) and a valve 9).

In this figure, a hydrogen-diluted diporane Q, a hydrogen-diluted 7-hin Q'→, and a hydrogen or helium carrier gas Qυ are shown. The silane was added to the cylinder ψ)K, passed through the J1 force 1,1ε preconditioner, and was then piped from the pulp box 9 to the cell.

In such a PCVD apparatus, Yang-8 without adding electric energy (4) is equivalent to LPOVD by 2.

After evacuating the Hidden-C reactor, including the piping, the vacuum was sufficiently evacuated (below IXlo-'torr), and then fluorine-containing silane was poured into the reactor to bring the temperature up to 25,060 degrees. The pressure inside the reactor was set to 0.1 Torr, and IOW was added as electrical energy. The board is 10 here.
cm' is 161 and is placed across a gap of 4 cm.

If silane is 30ccZ and fluorine/sila/ is 5 parts, fluorine is l, 5007 parts);+,,':L people.

Then, the reaction equation shown in Figure 2 occurs inside the reactor,
A; - In the non-single crystal semiconductor formed as a result ゛vr
H:p cumulative is less than or equal to IX10 crr+', preferably 1x10 to lXl0C! I was able to lower it by nK't. This is called the infrared absorption spectrum or engineering MA (
It was detected using an ion micro analyzer).

Managed by light.

Figure 2 r (Oi1suJ', ii,, rJA' (3
0%31) ``'C'; h 60 As a result, the non-silica crystalline silicon contained hydrogen and also partially contained conventional fluorine to form the form L).

At this time, if there is generally no fluorine, the formula (3 reactions also take place, and as a result, the reaction product is mixed with S 10 x ).In addition, the formula (33) (', 34) because the intermediate reaction occurs, 5
It was found that i-OH was also mixed into the water at the same time.

However, when fluorine is mixed into this reaction equation as shown in equation (31)K, fluorine'! f, hydrogen fluoride is expressed by the formula (
35) (36) K As shown, it was found that 5 inL was dehydrated and the reaction of RI (compound or hydroxide) of silicon could be prevented from rusting.

Furthermore, rather than using this reaction FiSiF as a reactive gas, it is important to use fluorine (or hydrogen fluoride (HF), silane-based) ~30W silicon 11
4-R〉cho does not make 〆3. This is clearly chemically stable SiF, ld
, it is clear that it is a secondary product.

Thus, by adding fluorine or hydrogen fluoride, the amount of oxide or hydroxide in the reaction product can be sufficiently reduced. And the range of addition of fluorine is the third
The curve shown in the figure (the shaded area (38) surrounded by three) was optimal.

No deoxidizing reaction could be expected. It is also possible to increase the amount of fluorine added to 20% or more, but if there are too many ridges, the piping system or reactor is likely to be etched, and as a result, total fluorine impurities are likely to enter. ~10% was optimal.

The temperature at which the reaction product is produced is also not 250'O but 150
At ~300°OR, 7; ji dl was preferred.

However, when the temperature reached 500 to 'i'oo'o, simple r, pCvD was sufficient and no electrical energy was required.

When a polysilane (for example, 5 itl-) was used instead of the above-mentioned monosilane, LPCVD was possible at 300 to 500°C. It was effective to add 1 to 10 fluorine at that time.

Figure 4 shows a semi-structured layer of KO, 5μ on a glass substrate parallel to f.
The electrical conductivity characteristics were investigated by providing an f1lf pole. Figure 4 particularly shows the properties (44) to (48) of the method of the present invention when fluorine or hydrogen fluoride is cooled, and the layer properties (44) to (48) when no fluorine or hydrogen fluoride is added.
39) to (43) are shown.

In the drawing, area (49) shows 1 dark change and 10 (
It has a value on the order of ncJ. KotoKAMI (10
0mW/Q m L) f area (50) When irradiated with K, conventionally it is a curve? a(40)K as shown < I X 10'
(A C! m5' and after continuous irradiation for 2 hours approximately 1
That value had deteriorated.

On the other hand, I'i 8J] Koi-CFi, that. Wow, 5. 1,1. It was about an order of magnitude larger than 6', and furthermore, when irradiated with continuous light, almost no deterioration was seen as seen in curve (45)+.

Furthermore, in the conventional example, the dark conversion conductivity after irradiation in the region (51) shows a deterioration of no order of magnitude of (3'') (' 1) S', but in the present invention, (44) and (46)?,! [n11
〇 When heating is further performed at 150'O, the conventional example shows the curve (
41) becomes (42), there is no improvement in the characteristics of ηlj, but the subsequent region (when light irradiation is performed at 5 points, curve 0 step and curve <40) show deterioration of characteristics. That is, in the conventional example, the electrical conductivity is small as shown in (5), and the Q+ property of deterioration is observed by light irradiation.

However, in the present invention, the electrical conductivity was as high as (54), and almost no deterioration of the characteristics was observed with or without light irradiation and with or without thermal annealing.

Here, as shown in Fig. 1, boron is added in a doping system of 10'' to 5XlO''C, typically 2X10'' to 1
By incorporating Xl6'cI71□J, this boron change could be further completely removed.

Figure 5 shows the photodegradation characteristics (Photo) of the conventional example in Figure 4.
o-engine induced Effect is called 1P-engine E,
This shows the principle of Stezleronski (also known as 7JJJ) and the characteristics and principles of the present invention.

That is, (A) is Ti f, Y f? If there is a bond with [j in A, SiO is formed in this part, which deteriorates electrical conduction. For this reason, FIG. 4 (53) and (49) are created. 4"1: VC, which has the spin (55) (5a) due to the 0H group in the opposite direction. There is no significant change in electrical conduction due to this 8l-OH. However, the curves (40) (43) in Figure 4
When irradiated with light, especially ultraviolet iiη, as seen in K, one of the 8l
The orientation of the -OH group changes. Because of the two balls, the electrical conductivity decreases exponentially according to the amount of light, as shown by curves (40) and (43).This is 150
Since the heat treatment at temperatures higher than 0.degree. C. causes the heat 4.degree.

Since this reversible cycle occurs repeatedly, the lp performance deteriorates. This model was created by Akito Motomoto and is currently being submitted to Physical Review Letters.

Furthermore, as shown in this book, when fluorine or hydrogen fluoride is added, oxygen can be completely or completely removed as shown in Figure 5 (D), and at the same time, the dangling bonds of silicon can be neutralized. Due to the contribution of hydrogen and fluorine, the fourth
As shown in Figure 5, the electrical conductivity is improved and the properties do not deteriorate due to the reversible process of the 5i-OH group.

Furthermore, if K hz C and oxygen still remain in the silicon of the present invention, as shown in FIG. 5(K), 34? boron and 5i-OH were mixed as shown in FIG. As a result, we were able to further improve the electrical conductivity.

In this embodiment, as shown in FIG. 1, the inner wall of the cylinder was coated with 1qty of gold, dioxide, or ≧d silicon to prevent the reaction between the cylinder and fluorine in the cylinder. Alternatively, a stainless steel cylinder 9 was used, the inner wall of which was treated with plasma hydrogen oxide and, in addition, a plasma cylinder 1f.

In this way, 7 pieces of 0.1 to 20% and the rest of silane, Kono J-skin silane, were added to lo=30Kg/cm"c.
It could be filled under high pressure, and its properties were sufficiently stable over I4-.

In this invention, silane mixed with fluorine or hydrogen fluoride was used in a high-pressure container.

However, in FIG.
The silane may be diluted to 1 to 10% and introduced, and only silane may be introduced from the zero point, and mixed in a doping system.

The viscosity can be further improved by examining the characteristics shown in Figure 3.

1 for this invention? This indicates an intrinsic silicon film containing no more than 0.001 inch of P- or N-type impurities.

However, it is also possible to create a P- or N-type half 2', "4'+ body" by introducing N-valent or V-valent impurities. B i X Or-y ((0< x, < 1
) can also be made.

In addition, S 1 with silicon as the main component by 4 Germans
It is also possible to make XGe+-, I (0<X<1).

Furthermore, a conversion device or an IGFE
, Stone collection 1 circuit It % l ;, :, l' f(
)5++ to Ll, high ir; :'NtI semiconductor device I
V1' can be put to practical use, and its industrial value is great.

[Brief explanation of the drawing]

Figure 1 shows an overview of the OVD device used in the present invention. Figure 2 shows the chemical reaction formula used in the present invention.
FIG. 3 shows the area of jl:1 required for Honkari JK. FIG. 4 shows changes in the electrical conductivity of the Kinoi IJil and the conventional example. 5th] indicates the 16.1 ratio of the bond coordination in the present invention and the conventional example. 5iH4-------→ S, -1-2H1----
-(Wonos, H, +2 l-1-~ SH+ 2)
IF -----(?I)Si) 1400, -
-U S α+2Hxj ---(a2)02+
2) -12-m-→2HtO↑ ~---(99
)S, H3+2H10---1 5102+ 4H ↑ -----C34)S;Oz'2h +2)4m
-) 5r-V*1+ 2HtOi ---tq
s) S, α+4) -IF --1 Si):, D+2HtO4---t9g) Replacement 91a 0-00Q/ 0-001 0.01
0. J //@3(2) g8 questions (kr) Sheep 4 ■ 0 S. (E) (A) (B) (C) CD) ♂, -B-5゜$l

Claims (1)

[Claims] Fluorine or hydrogen fluoride is added to silane mixed with oxygen or oxides of 11 molar proportion or less.
The mixed reactive gas is introduced into a reactor maintained at 1 atmosphere or less, and heat or electrical energy is supplied to cause a thermochemical reaction or a plasma chemical reaction. A gas phase reaction method characterized by forming a non-single crystal semiconductor film mainly composed of silicon. 2. In claim 1, Silane d! 9 j
, H,'IH or S 1 n Hi*+z(n 2'
”) A gas phase reaction method characterized by consisting of 0: ty1% Ita'C!
.