JPS60242612A - Deposition film forming method - Google Patents

Abstract

PURPOSE:To enable to form a thick deposition film of large area by a method wherein exciting energy is obtained using a specific annular silane compound, and a deposition film containing silicon atoms is formed using low level heat energy. CONSTITUTION:Pertaining to a method wherein the excitation and decompositional condition of row gas are formed by giving heat energy and, especially, an amorphous silicon (a-Si) deposition film is formed on a specific supporting member, an a-Si deposition film can be formed with low energy level and high film- forming speed using the annular silane compound in the mixed condition with a halogenide as the raw gas to be decomposed by heat energy, which is indicated by a general formula (provided that the n in the above-mentioned formula indicates 3, 4 or 5, and R indicates H or SiH3). Also, the a-Si deposition film which is excellent in uniformity of optical characteristics and stability in quality can be formed. Said deposition film is formed inside a deposition chamber 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a deposited film forming method for forming a photoconductive film, a semiconductor film, or an insulating film on a predetermined support using heat as excitation energy. By applying amorphous silicon (hereinafter referred to as a-), amorphous silicon (hereinafter a-
8i).

Conventionally, as a deposited film forming method for a-8i, Si)
A glow discharge deposition method and a thermal energy deposition method using I or 5t2H6 as a raw material are known. That is, these deposition methods use SiH or 5
i2H, is decomposed by electrical energy or thermal energy (excitation energy) to form a deposited film of a-8i on a support, and the deposited film formed is a photoconductive film,
It is used for various purposes as a semiconductor or insulating film.

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 High-power discharge has a large effect on the film during production, making it difficult to ensure the uniformity of electrical and optical properties and quality stability of the formed film, resulting in disturbances on the film surface during deposition and damage to the inside of the deposited film. Prone to defects. 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, the thermal energy deposition method also requires a high temperature of 400°C or higher, which limits the support materials that can be used, and in addition, useful bonded hydrogen atoms in the desired a-8i are separated. Since the probability increases, it is difficult to obtain desired characteristics.

Therefore, one way to solve these problems is to
A-9i low heat thermal energy deposition method (thermal CVD) using silicon compounds other than 5tn4.5i2u as raw material
) is attracting attention.

This low-calorie thermal energy deposition method uses low-temperature heating instead of glow discharge or high-temperature heating in the above-mentioned methods as excitation energy, and allows the production of a-8i 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, making it possible to form a high-quality film that maintains uniformity with lower energy consumption than the above-mentioned deposition method. It is easy to control and stable reproducibility can be obtained, and there is also the advantage that there is no need to heat the support to a high temperature and that selectivity to the support is widened.

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. We are currently working on providing thermal energy deposition methods that can be used.

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

As a result of extensive studies, the present invention has achieved these objectives by using the following general formula as a raw material gas decomposed by thermal energy: (However, in the above formula, n is 3.4 or 5, R is H or
The present inventors have discovered that this can be achieved by using a cyclic silane compound represented by (iH3) in a mixed state with a halogen compound. , the following general formula; (
However, in the above formula, n is 3, 4 or 5. R is H or fl
A gaseous atmosphere of a cyclic silane compound (representing 81H3) and a halogen compound is formed, and these compounds are heated using thermal energy.

A deposited film containing silicon atoms is formed on the support by excitation and decomposition.

The raw material for forming the a-8i deposited film used in the method of the present invention has the following general formula: (However, in the above formula, n is 3.4t or 5, R is H or S
It is a cyclic silane compound represented by iH3).

Examples of such cyclic silane compounds include the following.

/f61 Scrap 2' A3 /VL4 45 However, such cyclic silane compounds are efficient when thermal energy is used as excitation energy.
Excitation and decomposition cannot be obtained, and a good film formation rate cannot be obtained.

In the method of the present invention, a halogen compound is mixed with the cyclic silane compound in order to more efficiently promote the excitation decomposition of the cyclic silane compound by thermal energy.

The halogen compound mixed with the cyclic silane compound in the method of the present invention is one that can promote halogen atoms well. Examples of such halogen compounds include halogen gases such as C'2*Br2 eI, , F, and the like.

In the method of the present invention, the proportion of the halogen compound mixed in the raw material compound for forming the a-8i film or the amount of a used
0.01V01X to 65VOIN, although it varies depending on the raw materials for forming the 8i film and the cage of the halogen compound.
Preferably 0. It is used within the range of IVo1% to 5QVo1%.

In addition, in the cyclic silane compound represented by the above general formula, n is 6.
The above substances, in a mixed state with a halogen compound,
It is expected that the desired deposited film can be obtained by easy decomposition and low-energy excitation, but contrary to expectations, the quality of the photoconductive film and semiconductor film is poor, and in addition, defects on the surface of the film and the deposited film It was found that there was a lot of turbulence within the film, resulting in an uneven film. Therefore, if such a cyclic silane compound is used, it is difficult to control the production of the deposited film. Further, when n in the above formula is 2, it is also considered as a cyclic silane compound, but this compound is unstable and therefore difficult to isolate at present.

Therefore, n in the above formula is preferably 3.44 #-i5.

Next, thermal energy is applied to the silicon compound gas introduced into the deposition chamber using a Joule heat generating element, 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. Regarding 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 conduction heat the support surface, thermally excite the raw material gas near the surface, thermally decompose it, and generate decomposition products. Deposit the material onto the surface of the support.

Alternatively, it is also possible to place the heater close to 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-8i on a support.

Formation of the deposited film takes place inside the deposition chamber 1.

Reference numeral 3 placed inside the deposition chamber 1 is a support base on which a support is placed.

Reference numeral 4 denotes a heater for heating the support, and power is supplied to the heater 4 through a conductor 5. A gas introduction pipe for introducing a-8t raw material gas 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 a gas supply source 9+10+11t12 for supplying the raw material gas and gases such as carrier gas used as necessary. In order to measure the flow of each gas flowing out toward the deposited film 1 from the gas supply source 9s10°11t12, a corresponding flow meter 15-1.15-2.15-3.15-4 is used.
Branched gas introduction pipe 17-1.17-2.1 corresponding to
It is provided in the middle of 7-3.17-4. Valve 14-1.14-2.14-3 before and after each flow meter
．． 14-4.16-1.16-2.16-3.16-4
are provided and by adjusting these valves) a predetermined flow rate of gas can be supplied. 1:3-1゜13-2.
13-3 and 13-4 are pressure meters, which are used to measure the pressure on the high pressure side of the corresponding flow meter.

The gases that have passed 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).

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

However, if a single raw material gas is used, one gas supply source is sufficient. However, when two types of raw material gases are mixed and used, or when a single raw material gas (catalyst gas, carrier gas, etc.) is mixed, two or more 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 source 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-8t can be formed in the following manner.

First, the support body 2 is set on the support stand 3 in the deposition chamber 1.

Various types of supports 2 can be used depending on the purpose of the deposited film formed. Examples of materials that can form the support include N1CL stainless steel, AI, Crs Mob Au, Nb, Ta, V,
Metals such as Ti, Pt, Pd or alloys thereof,
Semiconducting supports include semiconductors such as Sts Ge, and electrically insulating supports include polyester, polyethylene,
Examples include synthetic resins such as polycarbonate 1, cellulose acetate, polypropylene, polyvinyl chloride, 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 about ~300°C, among the materials for forming the support mentioned above, it is possible to use materials with high heat resistance that cannot be applied to conventional glow discharge deposition methods or conventional thermal energy deposition methods. It is now possible to use supports made of low material.

After the support 2 is placed on the support stand 3 in the deposition chamber 1 in this manner, 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 less than 5 x 10' Torr, preferably 10
Torr or less is desirable.

When an electric heater 4 is used as a means for applying thermal energy, once the pressure inside the deposition chamber 1 has been reduced, the heater 4 is energized to heat the support 3 to a predetermined temperature. The temperature of the support at this time is 150 to 300°C, preferably 20°C.
The temperature is 0 to 250°C.

As described above, since the support temperature is relatively low in the method of the present invention, it is possible to use the glow discharge deposition method or the 5iH4H5i method.
Since high temperature heating of the support is not required as in thermal energy deposition methods using tHa as a raw material, the energy consumption required for this process can be saved.

Next, the valves 14-1 and 16-1 of the supply source 9 storing the gases of the raw material compound (one or more) for forming the a-8i film mentioned above are opened, and the raw material gas is deposited. Room 1
Send it inside.

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 10 to 100
08CCM, preferably 20-5o.

SCCM range is preferred.

The pressure of the source gas in the deposition chamber 1 is 1o-2 to 1o.

Torr, preferably maintained in the range of 10 to I Torr.

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 a-8i, which is a product, 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 forming rate of about 5 to 50 λ/see can be obtained. a
Decomposition products other than -'St 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 it is applied with a low amount of heat rather than with high heat, the energy is always applied uniformly to a predetermined space occupied by the raw material gas to be applied. can.

There is no effect of high-power radiation on the deposited film during the waveform process, as observed in the glow discharge deposition method. The formation of the deposited film continues while maintaining the temperature.

In this way, an a-8i film is formed on the support 2, and a
When the desired film thickness of -8i is obtained, the application of thermal energy from the heater 4 is stopped, and further [pulp 14-1
．． 16-1 is closed and the supply of raw material gas is stopped. a-
The thickness of the Si film is appropriately selected depending on the intended use of the formed a-8i film.

Next, after the gas in the deposition chamber is removed by driving an exhaust device (not shown), the pulp 21 is opened when the support and the deposited film have reached 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-8i film is formed is taken out.

The a-8f film thus formed on the support by the method of the present invention is an a-8i film with excellent uniformity of electrical and optical properties and stability of quality.

In addition, in one example of the method of the present invention explained above, M! Although a private membrane was formed, the method of the present invention is not limited thereto, and the method of the present invention can also be carried out under normal pressure or under pressurized pressure, as desired.

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 raw material gas that is easily excited and decomposed by the thermal energy is used. a at level
It has become possible to form a -8im film, and it has become possible to form a whole a-8i 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 gelatin discharge, deposition methods, or conventional thermal energy deposition methods can also be used. It also became possible to save energy consumption required for high temperature heating of the support.

Hereinafter, the method of the present invention will be explained in more detail according to examples.

Example 1 Using the apparatus shown in FIG. 1, using the above-mentioned silane compound 1 as the raw material for forming the a-8i deposited film, and using 2 as the halogen compound, the a-8i (Amorphous-5i) The film was formed as described in F below. First, a support (polyethylene terephthalate) is placed on the support stand 3 in the deposition chamber 1, and the entire gas exhaust pipe 20 is passed through the deposition chamber 1 using an exhaust device (not shown) to pump the inside of the deposition chamber 1 for 10'l.
'orr VC pressure is reduced, the heater 4 is energized to maintain the support f4 temperature at 225°C, and then the valve 14-1.16-1 of the raw material supply tank 9 filled with cyclic sila/compound N1 and Pulp 14 in filled source 29. -5, 1
Open each 6-5 and check the raw material gas? and a halogen compound gas were introduced into the deposition chamber 1 TIc.

At this time, while measuring with the corresponding flow meters 15-1 and 15-5, the gas flow rate of the cyclic silane compound 1 was measured at 1508.
For CCM, the gas flow rate of (■) was adjusted to 308 CCM.

Next, the pressure inside the deposition chamber was kept at 0.1 Torr, and the thickness was 5
An a-8i film of oooA was deposited on support 2 at a deposition rate of 281/sec. Note that the thermal energy was uniformly applied to the gas flowing near the entire support 2 disposed in the deposition chamber 1. At this time, decomposition products other than a-8i and surplus raw material gas that has not been decomposed are discharged through the gas exhaust pipe 20, while new raw material gas and halogen compound gas are continuously supplied through the gas introduction pipe 17.30. was supplied to.

A-8 thus formed by the method of the present invention
For evaluation of the i-film, a comb-shaped At gap electrode (length 250 μm, width 5 yen) was further formed on each of the a-Si films formed on the substrate, and a photocurrent (photocurrent) was formed. This was done by measuring the irradiation intensity (AMI; about 100 mW/cf) and the dark ILE current, and calculating the photoconductivity σp and the ratio of the photoconductivity σp to the dark conductivity σd (σp/σd).

Note that the gap electrode is a
-8i film was placed in a vapor deposition tank, and the cypress was heated to 1O-Torr once.
After reducing the pressure to a vacuum level of 5, the vacuum level was adjusted to 10 Torr, and the deposition rate was increased to 20
/sec, with a film thickness of tsooX, AI is a-8i
It was deposited on a film, and then etched using a pattern mask having a predetermined shape to form a butter/layer.

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

Examples 2 and 3 Br as a compound/(Example 2) and II'i
CI, (Example 3) was used to form a type I a-8i film in the same manner as in Example I, and the obtained a-8i film was formed in the same manner as in Example I.
The Si film was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.

To actual fA&N4・12 a-81 Take the raw materials and halogen compounds for forming the deposited film, and add the cyclic silane compound 1'l!12゜i3 mentioned above.
, l'i4 and 12. A-8! was carried out in the same manner as in Example 1 except that Br2, ct, and o were each used in combination and the hydrogen gas flow rate was set as shown in Tables 1 and 2. A film was deposited. The obtained a-8i film was evaluated in the same manner as in Example 1.

The evaluation results are shown in Tables 1 and 2.

Comparative Examples 1 to 4 The cyclic silane compounds N11l, l'111-12, positive 3.
An a-Si film was deposited in the same manner as in Example 1 except that N4 was used and no halogen compound was used.

The obtained a-8i film was evaluated in the same manner as in Example 1.

The evaluation results are shown in Tables 1 and 2.

To summarize the results of Examples 1 to 12 and Comparative Examples 1 to 4 above, as shown in the evaluation results in Tables 1 and 2, the film formation rate was When comparing corresponding Examples and Comparative Examples in which the halogen compound was mixed, the film formation rate was about 2 to 6 times higher when the halogen compound was mixed than when it was not mixed. Generally speaking, the rate of promotion of film formation continuity depending on the type of
Br, , I! Largest in order of

Furthermore, the a-S'i films formed in this example had good electrical properties as well.

Table 1 Yo2σP: 1 area (Ω・Cm)−1 Table 2 Yo2σP: 9 solutions (Ω・cm)−1

[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 6-1.6-2゜6-3: Gas flow 9, 10, 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 introduction pipe Nanato = Shichiushi 20: Gas exhaust pipe Applicant Canon Co., Ltd.

Claims (1)

[Claims] (1) In the deposition chamber in which the support is placed, the following general formula; (However, in the above formula, n is 3.4 or 5.R is H or
1H3) and a halogen compound, and applying thermal energy to these compounds to form a deposited film containing silicon atoms on the support. How to form a film.