JPS60221573A - Formation of deposited film - Google Patents

Abstract

PURPOSE:To form a deposited film contg. Si atom at a high film forming speed with low energy level by forming a gaseous atmosphere consisting of a specific Si compd. in a deposition chamber and exciting and decomposing the compd. by light energy. CONSTITUTION:The inside of the deposition chamber 1 in which a substrate 2 is set is evacuated and the substrate 2 is heated by a heater 4. Gaseous raw materials are fed into the chamber 1 from supply sources 9-12 while the flow rates thereof are regulated to form the gaseous atmosphere consisting of the Si compd. expressed by R<1>-(Si.R<2>R<3>)n-R<4>. In the formula, R<1>, R<4> denote halogen- substd. phenyl group, naphthyl group, etc., R<2>, R<3> denote H or CH<3> group, n denotes 3-7. A light energy device 7 is driven in such atmosphere to irradiate the light energy 8 to the gaseous raw materials. The photoexcitation and photodecomposition of the gaseous raw material flowing near the substrate 2 are thus accelerated and the a-Si, etc. which are the formed material are deposited on the substrate 2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a deposited film on a special holiday using light as excitation energy, and more specifically, by applying excitation energy such as light or light and optionally heat, Create an excited and decomposed state of the raw material gas, and deposit it on a predetermined support, especially amorphous silicon (hereinafter abbreviated as a-5i).
The present invention relates to a method of forming a deposited film of.

Conventionally, methods for forming deposited films of a-9i include SiH4,
Alternatively, a glow discharge deposition method and a thermal energy deposition method using Si2H6 as a raw material are known. That is, these deposition methods use SiH4 or Si2H as a raw material gas.
6 as electrician energy or thermal energy (excitation energy)
This is a method in which a deposited film of a-3i is formed on a support by decomposing the film, and the deposited film thus formed is used for various purposes such as a photoconductive film, a semiconductor film, or an insulating film.

However, in the glow discharge deposition method in which the deposited film is formed using a high-power discharge, it is difficult to control stable conditions with reproducibility, such as not always being able to obtain a uniform discharge distribution state. It is difficult to ensure the uniformity of electrical and optical properties and stability of quality of the film deposited during film formation, and the film surface is easily disturbed during deposition and defects within the deposited film are likely to occur. In particular, it has been extremely difficult to form a large-area or thick deposited film with uniform electrical and optical characteristics 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 useful bonded hydrogen atoms in the desired a-5i will be detached increases, making it difficult to obtain the desired properties.

Therefore, one way to solve these problems is to
A-Si optical energy deposition (photo-CVO) using SiH4 and Si2H6 as raw materials has recently been attracting attention.

This optical energy deposition method uses light as the excitation energy instead of glow discharge or heat in the above-mentioned methods, and allows the production of deposited films of a-9i to be performed at low energy levels. Ta. In addition, it is easy to uniformly irradiate the raw material gas with light energy, and it is 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, stable reproducibility is obtained, and there is no need to heat the support to a high temperature, and the selectivity for the support is widened.

However, with such optical energy deposition methods using SiH4 and Si2H6 as raw materials, there is a limit to how much efficient decomposition can be expected, and therefore the film formation speed cannot be improved, making it difficult to mass-produce. It has been pointed out that there is a problem.

The present invention was developed in view of these problems, and it is possible to form a deposited film containing silicon atoms at a low energy level at a high film formation rate while maintaining high quality by using light as excitation energy. An object of the present invention is to provide a light energy deposition method.

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 a compound containing silicon atoms and carbon atoms and having a chain structure constituted by at least silicon atoms as a raw material gas that is decomposed by light energy. It has been completed by discovering what can be achieved by doing so.

That is, in the deposited film forming method of the present invention, in a deposition chamber in which a support is arranged, the following general formula; represents a naphthyl group, an alkyl group having 1 to 11 carbon atoms, R2 and R3 each independently represent H or a CH3 group, n
represents an integer from 3 to 7), and the compound is excited and decomposed using light energy, thereby containing silicon atoms on the support. It is characterized by forming a deposited film.

The raw material for forming a deposited film used in the method of the present invention is a compound containing silicon atoms and carbon atoms and having a chain structure composed of at least silicon atoms, and is easily excited by light energy. , is characterized by being decomposable, and is represented by the general formula above.

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 excitation energy and is susceptible to radical decomposition. On the other hand, as the number of directly bonded silicon atoms in the compound increases, radical decomposition becomes easier due to lower excitation energy;
If the number of bonding silicon atoms is 8 or more, the quality of the formed a-3i film will deteriorate, which is not preferable.

Therefore, in order to efficiently excite and decompose and deposit a high-quality a-9i film, the number of silicon atoms in the compound is preferably 3 to 7, more preferably 3 to 6. Optimally, the force is preferably 3 to 5.

Furthermore, when R1 or R2 in the above formula is an alkyl group, the number of carbon atoms in the alkyl group is l -11, which is easy to synthesize, easily gasifies, and has a high decomposition efficiency with light energy. It is also suitable for use in the method of the present invention.

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

Notification I G)13-9i)+2-9i)12-9iH2
-C) 13A, 2 CI(3(C:t(2)2-(S
iH2)4-(CH2)2CH3A, 3CH3(C
H2) 2-(SiH2)s-(C)I2)2cH3 muscle 4
CL(CH2)n-(SiH2)s-(CHz)+C
H3 notification 5 (CH3)2CH-CH2-(SiH2)4
Jl:R2-C)l(CI(3h notification 6 (CH3h(H)
-(SiH2-CH(CR3)2 Notification 8 O1e-(Si
t(2) Defense C1d6.10 CH3<CH2h (S
iH2)3-5iH2,J,II CH3(C)I2)
2-(SiH2)8Br4,12(CH3)3Si-
9! H2-3i (CH3)3 notification 13 CH3 (C:Hz
h 5i(CH3h-(SiH2)2-9i (CIi
31h-(c1 Sat hC■-13 414(C)13)2C)1-C)1z-3i(CH3
h-9iH2-3i(CH2h-CI(2-C)l(C
)l, ) 2 Notification 15 CH3-CH2-3i(CH3)2-Si(C
:R3)2-9i(CH3)2-CH2-CH3 A, 1t3 Cj-, @-8i(CH3h 5iI(2
-3i142-8 i (C1-13)2ku◇-ctl
o, 19 R4-(Si)ICR3)36Br゛Notification 2
0 (CR3), CH-CR2-Si(CH3h-(S
ithhIn the method of the present invention, such a silicon compound is introduced into the deposition chamber so as to be in a gaseous state at least within the deposition chamber, and is irradiated with light energy.
This is excited and decomposed, and a deposited film (a-Sil) containing silicon atoms is formed on a support placed in the deposition chamber.

In the present invention, light energy refers to energy rays that can provide sufficient excitation energy when irradiated to the raw material gas, which can excite and decompose the raw material gas and deposit decomposition products. Any wavelength can be used as long as it has a wavelength range. Examples of such light energy include ultraviolet rays, infrared rays, visible light, X-rays, and gamma rays.

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.

Reference numeral 3 placed inside the deposition chamber 1 is a support base on which the support body 2 is placed.

4 is a heater for heating the support, and the road! The heater is powered by Q5. A gas introduction pipe 17 is connected to the deposition chamber 1 for introducing a-51 raw material gas and gases such as a carrier gas used as necessary into the deposition chamber 1. The other end of this gas introduction pipe 17 is connected to the gas supply source 9.10.11.1 used for the above gas and if necessary.
It is connected to 2. Gas supply source 9, 10.11.1
In order to measure the flow rate of each gas flowing out from 2 toward the deposition chamber 1, a corresponding flow meter 15-1.15-
2,15-3.15-4 are provided in the middle of the corresponding branched gas introduction pipes 17-1.17-2.17-3.17-4. Valve 14-1 is installed before and after each flow meter.
．． 14-2.14-3. , 14-4.16-1゜16-
2.18-3.16-4 are provided, and by adjusting these valves a predetermined flow rate of gas can be supplied.

13-1.13-2.13-3.13-4 is a pressure meter, and is for measuring 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). 7
is a light energy generator.

If the deposition chamber l is not made of a transparent material such as quartz glass, a window for irradiating the light energy 8 may be provided.

In the present invention, the number of gas supplies [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 using a mixture of two or more raw material gases, or when mixing a catalyst gas, carrier gas, etc. with a single raw material gas, 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 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 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 NiCl, stainless steel, Al, Cr, Mo, Au, Nb, Ta, V,
Metals such as Ti, Pt, and Pd or alloys thereof; semiconductive supports include semiconductors such as Sl and Ge; electrically insulating supports include polyester, polyethylene, polycarbonate, cellulose, acetate, polypropylene, and polyester. Examples include synthetic resins such as vinyl 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 set at 50 to
Since the temperature can be relatively low at around 150°C, it is possible to use materials with low heat resistance that cannot be applied to the conventional glow discharge deposition method or thermal energy deposition method among the materials that form the support. It is now possible to use other supports.

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 5X 10'5 Torr, preferably 10''
It is desirable that the pressure is 6 Torr or less.

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 preferably 50 to 1500C1, more preferably 50 to 100C.

As described above, since the support temperature is relatively low in the method of the present invention, it is not necessary to heat the support to a high temperature as in glow discharge deposition method or thermal energy deposition method. The energy consumption required for this can be saved.

Next, the valves 14-1 and 16 of the supply source 9 in which the raw material compound gas for forming the a-8i film as mentioned above is stored.
-1 is opened, and the raw material gas is sent into the deposition chamber l. In addition, when using one or more raw material mixed gases, the supply source 9 may be filled with a mixture of these gases at a predetermined mixing ratio, as long as they do not react with each other.

At this time, the flow rate is adjusted while being measured by the corresponding flow meter 15-1, 15-2. Normally, the flow rate of the raw material gas is 1
0-10003CCM, preferably 20-5009CCM
A range of M is desirable.

The pressure of the source gas in the deposition chamber 1 is 10-2 to 1'0OTo.
rr, preferably maintained in the range of 10-2 to I Torr.

When the source gas is introduced into the deposition chamber 1, the optical energy generator 7 is driven to irradiate the source gas with optical energy.

As the light energy generating device 7, for example, a mercury lamp,
A xenon lamp, carbon dioxide laser, argon ion laser, excimer laser, or the like can be used.

An optical system (not shown) is incorporated so that the desired light energy generated by driving the light energy generating device 7 irradiates the support 2 installed in the deposition chamber 1.

The light energy can be applied uniformly to the gas flowing in the vicinity of the support 2 disposed in the deposition chamber 1 or by selectively controlling the irradiated portion.

In this way, optical energy is applied to the raw material gas flowing near the surface of the support 2, promoting photoexcitation and photodecomposition, 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 light energy.
A high deposition rate of ~100 A/see 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, light energy is used as excitation energy, and this light energy is applied so that it can always uniformly irradiate a predetermined space occupied by the raw material gas to be irradiated. It is easy to control using an optical system so that uneven distribution of energy does not occur, and it is also recognized in the glow discharge deposition method that the light energy itself is applied to the deposited film in the process of forming. There is no effect from high-power discharge, and there is no disturbance of the film surface during deposition or defects within the deposited film.
The formation of the first pattern of deposits continues while maintaining uniformity. especially,
Since light energy can be irradiated uniformly over a wide range, it has become possible to uniformly form a deposited film over a large area with high precision.

Further, by selectively controlling the irradiated portion of the light energy, it is possible to limit the portion on the support where the deposited film is formed.

In addition, the excitation and decomposition of the raw material gas by light energy in the present invention includes not only the case where the raw material gas is directly excited and decomposed by the light energy, but also the case where the light energy is absorbed by the raw material gas or the support and generates heat. This also includes cases where the light energy is converted into energy and the resulting thermal energy causes excitation and decomposition of the source gas, which is a derivative effect of light energy.

In this way, an a-3i film is formed on the support 2, and a
When the desired film thickness of -9i is obtained, light energy emission 4: Stops the injection of optical mulch from M7, closes pulp 14-1, 16-1, and stops supply of raw material gas. do. The thickness of the a-3i film is appropriately selected depending on the intended use of the formed a-Si film.

Next, by driving an exhaust device (not shown), the gas in the deposition chamber is expelled, and then the heater 4 is turned off. When the support and the deposited film reach room temperature, the pulp 21 is opened and the atmosphere is gradually introduced into the deposition chamber. Then, 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-9i film thus formed on the support by the method of the present invention is an a-5i 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 method is not limited to this, and the method of the present invention may be formed under normal pressure, under normal pressure, as desired. It can also be carried out under pressure.

According to the method of the present invention as described above, by using light energy as excitation energy and using a raw material that is easily excited and decomposed by the light energy, a low energy level can be achieved with a high film formation rate. a-3i at
It has become possible to form a deposited film, and it has become possible to form an a-5i 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 thermal energy deposition methods can be used, and the high temperature of the supports can also be used. It has become possible to save energy consumption required for heating.

Furthermore, the light energy can be easily controlled so that the energy can always be uniformly irradiated onto a predetermined space occupied by the source gas to be irradiated, and thick deposited films can be formed uniformly with high precision. In particular, since uniform irradiation can be performed over a wide range, it has become possible to form a deposited film uniformly and accurately even over a large area.

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

Example 1 Formation of a-9i (amorphous-3i)'H using the apparatus shown in FIG. was carried out 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 1, and the interior of the deposition chamber 1 is pumped through the gas exhaust pipe 2o by an exhaust device (not shown). The pressure was reduced to 10"6 Torr, the heater 4 was energized to maintain the support temperature at 50°C, and then the raw material supply source 9 filled with silicon compound was heated.
The valves 14-1 and 18-1 were opened, and the raw material gas was introduced into the deposition chamber 1.

At this time, the gas flow rate was adjusted to 15O5CGH while measuring with the corresponding flow meter 15-1. Next, the pressure inside the deposition chamber was reduced to 0. Maintained at I Torr, light intensity 100 mW
/cm' of light from a low-pressure mercury lamp is generated from the light energy generator 7 and irradiated perpendicularly to the support to form a mercury lamp with a thickness of 400 mm.
0A type 1 a-3i film, 15A/see c)
The film was deposited on the support 2 at a film formation rate. Note that the light energy was uniformly applied to the gas flowing in the vicinity of the entire support body 2 disposed in the deposition chamber 1. At this time, a-
Decomposition products other than 3i and undecomposed surplus raw material gas were discharged through the gas exhaust pipe 20, while new raw material gas was continuously supplied through the gas introduction pipe 17.

a-3 thus formed by the method of the present invention.
For evaluation of the i film, a comb-shaped A1 cap electrode (length 25
0p, width 5mm) to form a photocurrent (light irradiation intensity AM
This was carried out by measuring the dark current (I, about too mW/crry') 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
- Put the 3i film into a vapor deposition tank, and turn the tank once to 10' Torr.
After reducing the pressure to a vacuum level of
7) AI was deposited on the a-9i film to a certain thickness, 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 5 Each of the silicon compounds listed above (Examples 2 to 5) was used individually as a starting material for forming a deposited film, and the support temperature was indicated. A-3 of type I was prepared in the same manner as in Example 1 except that the settings were made as shown in 1.
An i film was formed, and the obtained a-9i film was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.

Comparative Example 1 I′y! ! An a-3i film was formed, and the obtained a-3i film was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.

To summarize the results of Examples 1 to 5 and Comparative Example 1 above,
As for the film formation rate, as shown in the evaluation results in Table 1, when light from a low-pressure mercury lamp with a light intensity of 100 mW/crn' was used and the support temperature was 50°C, Comparative Example 1 The film forming rate in Example 1.2 of the present invention was 15 A/sec, whereas the film forming rate in Example 1.2 of the present invention was 15 A/sec.
c and a good film formation rate were obtained, and Examples 1 to 1 of the present invention
In any case of 5, the photoconductivity σp is 3X10
'~1.5X10', and σp/σd is 5X]03~1
．． A good value of 2XIO' was obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an example of a deposited film forming apparatus used in the method of the present invention. l: Deposition chamber 2. Support 3: Support base 4: Heater 5: Conductor 6-1.6-2.8-3: Gas flow 7: Light energy generator 8: Light energy 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°18-1,1t (-2,16-3,18-4 , 21 + valve 1.5-1.15-2.15-3.15-4: flow meter 17.17-1.17-2.17-3.17
-4: Gas introduction pipe 20: Gas exhaust pipe

Claims (1)

[Claims] (1) In the deposition chamber in which the support is placed, the following general formula: % formula % (However, R1 and R4 are each independently a phenyl group or naphthyl group which may be substituted with halogen, and have 1 to 1 carbon atoms. Represents an alkyl group of 11 1172
and R3 each independently represent H or a CH3 group, and n represents an integer from 3 to 7), and the compound is excited using light energy, A method for forming a deposited MK film, characterized in that a deposited film containing silicon atoms is formed on the support by decomposition.