JPS60245129A - Forming method of accumulated film - Google Patents

Abstract

PURPOSE:To obtain an alpha-Si film having uniform and stable characteristic and quality on the prescribed support by applying thermal energy to gas atmosphere of Si compound of general formula of SinHmXr. CONSTITUTION:A valve of a supply source 9 of the prescribed Si compound which includes halogen X and m+r=2n+2, where n, m, r are 1 or larger integers such as H2SiBr2 is opened, the flow rate is regulated, and fed to a room 1. The room is reduced under pressure, a support 2 is heated by a heater 4 to approx. 250 deg.C, raw gas pressure is held at 10<-2>-1Torr, thermal energy is applied to raw base flowed near the surface of the support 2, thermally excited, thermally decomposed to accumulate alpha-Si. According to this configuration, the obtained alpha-Si film has uniform electrical and optical properties with stable quality, and can be formed on a low thermal resistance support.

Description

Detailed Description of the Invention The present invention utilizes heat as excitation energy to form a photoconductive film, a semiconductor film, or an insulating film on a predetermined support.
More specifically, regarding the method for forming a deposited film, in particular, amorphous silicon (hereinafter referred to as a
-Si (abbreviated as Si).

Conventionally, glow discharge deposition and thermal energy deposition using SiH4 or Si2H6 as a raw material are known as methods for forming a-3T deposited films. That is, these deposition methods use SiH4 or Si2 as a raw material gas.
This is a method of decomposing H6 using electrical energy or thermal energy (excitation energy) to form a deposited film of a-3T on a support, and the deposited film formed can be a photoconductive film, a semiconductor film, an insulating film, etc. It is used for various purposes.

However, in the glow discharge deposition method, in which the deposited film is formed under high-power discharge, it is difficult to control reproducible and stable conditions, such as not always achieving a uniform discharge distribution state, and furthermore, the film formation The high-power discharge has a large effect on the film inside the film, making it difficult to ensure the uniformity of electrical and optical properties and quality stability of the formed film, causing disturbances on the film surface during deposition, and damage to the inside of the deposited film. defects are likely to occur. In particular, it has been extremely difficult to form a thick deposited film with uniform electrical and optical properties using this method.

On the other hand, in the thermal energy deposition method, the temperature is usually 400°C.
Since the above-mentioned high temperature is required, the support material to be used is limited, and in addition, the probability that the useful bonded hydrogen atoms in the desired a-3i will be separated increases, making it difficult to obtain the desired properties.

Therefore, one way to solve these problems is to
A-3T low heat energy deposition method (thermal CVN) using silicon compounds other than SiH4 and Si2H6 as raw materials
is attracting attention.

This low-calorie thermal energy deposition method uses low-temperature heating instead of the glow discharge and high-temperature heating in the above-mentioned methods as excitation energy, and allows the production of a-3i deposited films at low energy levels. It is something that makes it possible.

In addition, the lower the temperature, the easier it is to uniformly heat the raw material gas, and the energy consumption is lower than that of the above-mentioned deposition method.
It is possible to form a high-quality film that maintains uniformity, it is easy to control manufacturing conditions, and stable reproducibility can be obtained, there is no need to heat the support to high temperatures, and there is good selectivity to the support. There is also the advantage of expanding.

The present invention has been made in view of the above points, and uses low-level thermal energy as excitation energy to form a deposited film containing silicon atoms at a high deposition rate while maintaining high quality at a low energy level. The object of the present invention is to provide a thermal energy deposition method that can be used.

Another object of the present invention is to form a high-quality deposited film that ensures uniform electrical and optical properties and stable quality even in the formation of a large-area, thick deposited film. The purpose is to provide a method that can be used.

The present invention has been completed based on the discovery that these objects can be achieved by using a silicon compound containing a halogen atom as a raw material gas that is decomposed by thermal energy.

That is, in the deposited film forming method of the present invention, in a deposition chamber in which a support is placed, the following general formula; By forming a gaseous atmosphere of a silicon compound represented by r = 2 n + 2) and using thermal energy to excite and decompose the compound, a deposit containing silicon atoms is formed on the support. It is characterized by forming a film.

The raw material for forming the deposited film used in the method of the present invention is a silicon compound containing halogen atoms, which is characterized by being easily excited and decomposed by thermal energy, and is represented by the above general formula. It will be done.

Among such compounds, n in the above formula is 3 to 7.
is preferably an integer of , more preferably 3 to 6,
Optimally, it is desirable to be an integer of 3 to 5. That is, when the number of silicon atoms in the compound is 3 or more, the bond between adjacent silicon atoms, especially the bond between a silicon atom sandwiched between two silicon atoms and another silicon atom bonded to the atom, It becomes unstable due to relatively low thermal energy and is susceptible to radical decomposition. On the other hand, as the number of directly bonded silicon atoms in a compound increases, radical decomposition becomes easier due to lower thermal energy, but when the number of bonded silicon atoms is 8 or more.

This is not preferable because the quality of the formed a-3t film deteriorates.

Therefore, in order to efficiently excite and decompose and deposit a high-quality a-St film, the number of silicon atoms in the compound is preferably 3 to 7, more preferably 3 to 6, and most preferably It is desirable that it is 3-5.

On the other hand, r halogen atoms represented by X in the above formula are 1
It is not limited to only seeds, but may be a mixture of several types.

The total number of halogen atoms in the compound is determined by m+n=r, but it is preferable that the total number of halogen atoms in the compound is smaller than the total number of hydrogen atoms.

The halogen atom contained in the silicon compound used in the method of the present invention is preferably a bromine atom or an iodine atom, with an iodine atom being more preferred. This is true for silicon-bromine or monoiodine bonds, especially silicon-iodine bonds.

This is because it is more unstable than the silicon-hydrogen bond and is easily excited and decomposed even with low energy such as thermal energy.

The silicon compound used in the method of the present invention is easily excited and decomposed by thermal energy.
Radicals such as HX, :5i2H, :5iH2X2 are generated, and these are further thermally excited and decomposed to form a high quality a-St film.

Typical silicon compounds used in the method of the present invention include the following compounds.

No, 1) 12siBr2 No, 2 H2S1I2 No, 3 H3SiF No, 4 H3SiBr No, 5 H3SiI No, 6 H3SiFI No, 7 H2S1CuI No, 8 H2S1B-I No, 9 (HBr2Si)2 No, 1 0 (HI2Si)2 No , 11 (H2FSi)2 No, 12 (H2C1Si)2 No, 13 (H2C1Si)2 No, 14 (H2ISi)2 No, 15 H45i2FI No, 16 H45t2CuI No, 17 H45i2BrI No, 18 H45i2FBr No, l 9 H4S i 2CJIB rNo, 2
0 H5Si2F No, 21 H5S i, Cl No, 22 I (5Si2Br No, 23 H5St2I F F C sentence C view 0 sentence No, 26 H6Si6F6 No, 27 H2S1I2 No, 28 H45t3Br4 No, 29 H45i3I4 No , 30 H6Si6F6 No. 31 H2S1I2 No, 32 H7Si3F No', 33 H6Si6F6 No, 34 H7Si3Br No, 35 H7St3I No, 36 eye-H45i2BrINo, 37 c
yc-)16si6Br6No, 38cyc-H45
i2FBrNo, 39 eye-H6Si6Cu6No
, 40 eye-H6Si6F6 No, 41 cyc-H2Si6F10 In the method of the present invention, such a silicon compound is introduced into the deposition chamber so that it becomes gaseous at least in the deposition chamber, and thermal energy is given to it. This is excited and decomposed,
A deposited film (a-3t film) containing silicon atoms is formed on a support placed in a deposition chamber.

Next, imparting thermal energy to the silicon compound gas introduced into the deposition chamber includes a Joule heat generating element;
This is carried out using high frequency heating means or the like.

Examples of the Joule heat generating element include heaters such as heating wires and heating plates, and examples of the high frequency heating means include induction heating and dielectric heating.

To explain the embodiment using the Joule heat generating element, the heater is brought into contact with or close to the back surface of the support to conductively heat the surface of the support, thermally excite and decompose the raw material gas near the surface, and the decomposition products are transferred to the surface of the support. to be deposited.

Alternatively, it is also possible to place the heater near the surface of the support.

Hereinafter, the method of the present invention will be explained in detail with reference to FIG.

FIG. 1 is a schematic diagram of a deposited film forming apparatus for forming a functional film such as a photoconductive film, a semiconductor film, or an insulating film made of a-3i on a support.

Formation of the deposited film takes place inside the deposition chamber 1. Deposition chamber l
Reference numeral 3 placed inside is a support stand on which the support body is placed.

Reference numeral 4 denotes a heater for heating the support, and power is supplied to the heater 4 through a conductive wire 5. The inside of the gas introduction pipe for introducing the raw material gas of a-3i and gases such as carrier gas used as needed into the deposition chamber 1 is connected to the deposition chamber 1.

The other end of this gas introduction pipe 17 is connected to gas supply sources 9, 10, 11, 12 for supplying the raw material gas and gases such as carrier gas used as necessary. In order to measure the flow rate of each gas flowing out from the gas supply sources 9, 10° 11.12 towards the deposition chamber 1, the corresponding flow meters 15-1.15-2.15-3.15-4 are installed. Corresponding branched waste introduction pipe 17-1゜17-2.17-3
．． It is installed in the middle of 17-4. Pulp 14-1.14-2.14-3.14- is placed before and after each flow meter.
4°16-1.16-2.16-3.16-4 are provided, and by adjusting these pulps, a predetermined flow rate of gas can be supplied. 13-1゜13-2.13-3.
13-4 is a pressure meter for measuring the pressure on the high pressure side of the corresponding flow meter.

The gases passing through the flow meters are mixed and introduced into the deposition chamber 1 under reduced pressure by an exhaust device (not shown). In addition, the pressure meter 18 measures the total pressure in the case of mixed gas.

A gas exhaust pipe 20 is connected to the deposition chamber 1 in order to reduce the pressure inside the deposition chamber 1 and to exhaust the introduced gas.

The other end of the gas exhaust pipe is connected to an exhaust device (not shown).

2 In the present invention, the number of waste supply sources 9, 10, 11, 12 can be increased or decreased as appropriate.

That is, when using a single raw material gas, one gas supply source is sufficient. However, when two types of raw material gases are mixed and used, or when a single gas (catalyst gas, carrier gas, etc.) is mixed, two or more gases are required.

Note that some raw materials do not turn into gas at room temperature and remain liquid, so when using liquid raw materials, a vaporizer (not shown) is installed. There are two types of vaporizers: those that utilize heating and boiling, and those that pass a carrier gas through a liquid raw material. The raw material gas obtained by vaporization is introduced into the deposition chamber 1 through a flow meter.

Using the apparatus shown in FIG. 1 and the method of the present invention, a deposited film consisting of a-3i can be formed in the following manner.

First, the support body 2 is set on the support stand 3 in the deposition chamber l.

Various types of supports 2 can be used depending on the purpose of the deposited film formed. Examples of materials that can form the conductive support include NiCu, Steer L/S, An, and Cr.

Mo, Au, Nb, Ta, V, Ti, Pt.

Metals such as Pd or alloys thereof; semiconductive supports include semiconductors such as St and Ge; and electrically insulating supports include
Polyester, polyethylene, polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride,
Examples include synthetic resins such as polyvinylidene chloride, polystyrene, and polyamide, glass, ceramics, and paper. The shape and size of the support 2 are determined as appropriate depending on the intended use.

In particular, in the method of the present invention, the temperature of the support is 150°C.
Since the temperature can be relatively low at ~300°C, among the materials forming the support, it is a material with low heat resistance that cannot be applied to conventional glow discharge deposition methods or thermal energy deposition methods. It has now become possible to use supports made of

After the support 2 is placed on the support stand 3L in the deposition chamber 1 in this way, the air in the deposition chamber is exhausted through the gas exhaust pipe 20 by an exhaust device (not shown) to reduce the pressure. The atmospheric pressure in the deposition chamber under reduced pressure is preferably 5X 1.0-5 Torr or less, preferably 10-6 Torr or less.

When an electric heater 4 is used as the thermal energy measuring means, the heater 4 is energized to heat the support 3 to a predetermined temperature after the pressure inside the deposition chamber 1 is reduced. The temperature of the support for this poem is 150-300℃, preferably 200-300℃
It is said to be 2500C.

As described above, since the support temperature is relatively low in the method of the present invention, it is possible to use glow discharge deposition method or SiH4,S
Because it does not require high-temperature heating of the support as in the thermal energy deposition method using i2H6 as a raw material,
The energy consumption required for this can be saved.

Next, the valves 14-1 and 16-1 of the supply source 9 in which the gases of the 5 raw material compounds (one or more) for forming the a-5i film as mentioned above are stored are opened, and the raw material gases are into the deposition chamber l.

At this time, the flow rate is adjusted while being measured by the corresponding flow meter 15-1. Usually, the flow rate of the raw material gas is lO~11
0003 cc, preferably in the range of 20 to 5003 CCM.

The pressure of the raw material gas in the deposition chamber 1 is 10-2 to 100 Torr.
r, preferably maintained in the range of 10-2 to ITorr.

In this way, thermal energy is imparted to the raw material gas flowing near the surface of the support 2, promoting thermal excitation and thermal decomposition, and the product a-3i is deposited on the support.

As mentioned above, the raw material gas used in the method of the present invention is easily excited and decomposed by thermal energy.
A high film formation rate of about 5 to 50 people/sec can be obtained. Decomposition products other than a-3i and undecomposed surplus raw material gas are discharged through the gas exhaust pipe 20, while new raw material gas is continuously supplied through the gas introduction pipe 17.

In the method of the present invention, thermal energy is used as excitation energy, but since the application is not a high amount of heat but a low amount of heat, the energy is always applied uniformly to a predetermined space occupied by the raw material gas to be provided. can.

The deposited film in the process of being formed is not affected by high-power discharge as observed in the glow discharge deposition method, and uniformity is maintained without disturbing the film surface or causing defects within the deposited film during deposition. The formation of the deposited film continues.

In this way, an a-St film is formed on the support 2, and a
When the desired film thickness of -3i is obtained, the application of thermal energy from the heater 4 is stopped, and further the valve 14-1.
16-1 is closed and the supply of raw material gas is stopped. a-3t
The film thickness of the film is appropriately selected depending on the purpose of the formed a-St film.

Next, after the gas in the deposition chamber is removed by driving an exhaust device (not shown), the valve 21 is opened when the support and the deposited film reach room temperature, and atmospheric air is gradually introduced into the deposition chamber.
The inside of the deposition chamber is returned to normal pressure, and the support on which the a-3i film is formed is taken out.

The a-gi film thus formed on the support by the method of the present invention is an a-3t film with excellent uniformity of electrical and optical properties and stability of quality.

In the example of the method of the present invention described above, the deposited film was formed under reduced pressure, but the present invention is not limited to this, and the method of the present invention can be formed under normal pressure or under pressure as desired. It can also be carried out under pressure.

According to the method of the present invention as described above, thermal energy with a low calorific value is used as excitation energy, and a source gas that is easily excited and decomposed by the thermal energy is used, so that a high film formation rate can be achieved. It has become possible to form an a-3t deposited film at a high energy level, and it has become possible to form an a-3i deposited film with excellent uniformity of electrical and optical properties and stability of quality.

Therefore, in the method of the present invention, supports made of materials with low heat resistance that cannot be applied to conventional glow discharge deposition methods or conventional thermal energy deposition methods can be used. It has become possible to save energy consumption required for high-temperature heating.

Hereinafter, the method of the present invention will be explained in more detail according to the examples.1 Using the apparatus shown in FIG.
-3t (Amol 77-St) film was formed as follows.

First, a support (trade name: Corning #7059, transparent conductive film (polyester base)) is set on the support stand 3 in the deposition chamber l, and passed through the gas exhaust pipe 20 to the exhaust device (
(not shown) to reduce the pressure in the deposition chamber 1 to 104 Torr, energize the heater 4 to maintain the support temperature at 220°C,
Next, a raw material supply source 9 filled with silicon compound No. 1
The valves 14-1 and 16-1 were opened, and the raw material gas was introduced into the deposition chamber 1.

At this time, the gas flow rate was adjusted to 150 SCCM while measuring with the corresponding flow meter 15-1. Next, the pressure inside the deposition chamber was kept at 0.1 Torr, and the thickness of the a-
A Si film was deposited on support 2 at a deposition rate of 47 people/sec.

Note that the thermal energy was uniformly applied to the gas flowing near the entire surface of the support 2 placed in the deposition chamber 1. At this time, decomposition products other than a-3i and surplus raw material gas that has not been decomposed are removed from the gas exhaust pipe 20.
Meanwhile, new raw material gas was continuously supplied through the gas introduction pipe 17.

Thus formed by the method of the present invention. a-3
Evaluation of the t-film was performed by adding a comb-shaped AI gap electrode (length 2
50 IL width 5 mm) and photocurrent (light irradiation intensity A
MI: approximately 100 mW/cm2) and the dark current was measured, and its photoconductivity σP and photoconductivity σP and dark conductivity σ were measured.
This was done by calculating the ratio (σP/σd) to d.

Note that the cap electrode is a
- Place the Si film in a vapor deposition tank and heat the nuclide once to 1O-6 Torr.
After reducing the pressure to a vacuum level of r, the vacuum level is reduced to 1O-5 Torr.
The deposition rate was 20 people/sec, and the deposition rate was 150.
A10 was deposited on the a-3i film to a film thickness of 0.05 mm, and this was etched using a pattern mask having a predetermined shape to form a pattern mask.

The obtained σP values and σP/σd ratios are shown in Table 1.

Examples 2 to 7 As starting materials for forming deposited films, the silicon compounds listed above No. 6, No. 14, No. 24
.

No. 26, No. 30, No. 32 (Examples 2 to 7) were used individually to form an a-Si film in the same manner as in Example 1, and the resulting a-3i film was Evaluation was made in the same manner as in Example 1. The evaluation results are shown in Table 1.

Comparative Example 1 An a-3i film was formed in the same manner as in Example 5 except that Si2H6 was used as the raw material for supplying Si, and the obtained a-3i film was evaluated in the same manner as in Example 1. . The evaluation results are shown in Table 1.

Examples 8 to 14 Silicon compounds No. 2, No. 10, and No. 13 listed above were used as starting materials for forming deposited films.

No, 14, No, 27, No, 30, N
o, 34 (Examples 8 to 14) individually,
The support temperature was set at 250°C and the same procedure as in Example 1 was carried out.
A-3i film was deposited. The obtained a-3t film was used in Example 1.
It was evaluated in the same manner. The evaluation results are shown in Table 2.

Comparative Example 2 An a-3i film was formed in the same manner as in Example 8 except that Si2H6 was used as the raw material for supplying Si, and the obtained a-3t film was evaluated in the same manner as in Example 5. . The evaluation results are shown in Table 2.

To summarize the results of Examples 1-14 and Comparative Example 1.2 above, as shown in the evaluation results in Tables 1 and 2, the film formation rate was lower when the support temperature was 220°C. , the film formation rate in Comparative Example 1 was 10 k/sec, whereas the film forming rate in Example 1.2 of the present invention was 47 k/sec, and the support Body temperature 25
When the temperature was 0°C, the film formation rate in Comparative Example 2 was 11 seconds/sec, whereas in Example 8 of the present invention.
In Example 13, a good film formation rate of 45 to 49 people/sec was obtained, and in any of Examples 1 to 34 of the present invention, the photoconductivity σP was 5X IO- 5~
9X 10-5, Mata σP/σd is 7X103~7X1
Showing a good value of 04 3 4

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an example of a deposited film forming apparatus used in the method of the present invention. 1: Deposition chamber 2: Support 3: Support 4: Heater 5: Conductor 6-1.8=2°6-3: Gas flow 9. to, 11° 12: Gas supply source 13-
1.13-2゜13-3.13-4.18: Pressure meter 14-1.14-2.14-3.14-4゜16-1
．． 16-2.16-3.16-4゜21; Valve 15
-1.15-2.15-3.15-4: Flow meter 17゜17-1.17-2.17-3.17-4: Gas inlet pipe Long assembly company nose 20: Gas exhaust pipe Applicant Canon 7 Co., Ltd.

Claims (1)

[Claims] (1) In the deposition chamber in which the support is placed, the following general formula; A method for forming a deposited film, comprising: forming a gaseous atmosphere of a silicon compound represented by (a) and applying thermal energy to the compound to form a deposited film containing silicon atoms on the support.