JPS60218836A - Deposited film forming method - Google Patents

Abstract

PURPOSE:To increase a film-forming rate while keeping high quality, by producing gas atmosphere of straight chain silicon hydride compound in a chamber including substrates and by forming each deposition film containing silicon over the respective substrates. CONSTITUTION:Gas atmosphere of straight chain silicon hydride compound expressed by a general expression: SinH2n+2 (n represents an integer of 4 or more) is produced in the chamber including substrates, and the compound is excited and decomposed by utilizing optical energy, forming each deposition film containing silicon over the respective substrates. The resulted deposition film may be crystalline or amorphous and the combination of silicon in the film may be from oligomer to polymer state. Moreover hydrogen atoms and halogen atoms, etc. in the raw material may be taken in the structure.

Description

Detailed Description of the Invention [Technical Field] The present invention relates to amorphous silicon (hereinafter referred to as a-8i) or polycrystalline silicon, which is useful as a deposited film containing silicon, a photoconductive film, a semiconductor film, an insulating film, etc. The present invention relates to a method suitable for forming a deposited film of crystalline silicon.

[Prior art]

Conventionally, the deposited film of A-81 was replaced with SiH4 or Si2.
It is known to form by a glow discharge deposition method or a thermal energy deposition method using H6 as a raw material. That is, 5I
It is well known to form a deposited film of A-81 on a substrate by exciting and decomposing H4 or 812H6 using electrical energy or thermal energy, and to utilize this film for various purposes.

However, when these 81H4 and S1□H6 are used as raw materials, in the glow discharge deposition method, the discharge energy has a large influence on the film being deposited under high output, and it is difficult to control the conditions to maintain reproducible and stable conditions. Especially for large areas,
This is noticeable when forming a thick deposited film.

In addition, the thermal energy deposition method also requires high temperatures, which limits the substrates that can be used, and also increases the probability that useful bonded hydrogen atoms in a-8i will detach due to high temperatures. This makes it difficult to obtain desired characteristics.

As described above, when forming a deposited film using 5IHa and 812H6, it is difficult to ensure uniform electrical and optical properties and quality stability, resulting in disturbances on the film surface and defects in the bulk during deposition. At present, there are still problems that need to be resolved, such as the ease of use.

Therefore, in recent years, in order to solve these problems, 5in4
A light energy deposition method of a-81 using Si2H6 as a raw material has been proposed and is attracting attention. According to this optical energy deposition method (photo-CVD method), the above-mentioned problems can be significantly improved due to the advantage that the A-81 deposited film can be produced at a low temperature. However, SiH4 and S under relatively small excitation energy such as light energy
With the optical energy deposition method using i2Hb as a raw material, dramatically efficient decomposition cannot be expected;
A new problem has arisen in that no improvement in film formation speed can be expected and there are difficulties in mass production.

The present invention has been made to solve these current problems.

[Purpose of the invention]

An object of the present invention is to provide a method for forming a silicon-containing deposited film that can maintain high quality and increase the film formation rate. Even in the case of membranes,
An object of the present invention is to provide a method for forming a deposited film that can produce a deposited film containing high quality silicon while ensuring uniform electrical and optical characteristics and stability of quality.

For the above purpose, the general formula: 5lnH is
Forming a gaseous atmosphere of a linear silicon hydride compound represented by 2n+2 (in the formula, n represents an integer of 4 or more), and exciting and decomposing the compound by using light energy. This is achieved by a deposited film forming method characterized by forming a deposited film containing silicon on the substrate.

[Embodiment]

The silicon-containing deposited film formed by the method of the present invention may be crystalline or amorphous, and the silicon bonds in the film may be in the form of a tilted form ranging from an orico-9mer form to a polymer form. Further, hydrogen atoms, halogen atoms, etc. in the raw materials may be incorporated into the structure.

Hereinafter, embodiments of the present invention will be described mainly in the case of an a-8i deposited film.

Although there is no particular restriction on the upper limit of the silicon number n of the cyclic hydrosilicated food of the general formula used in the present invention, it is preferable that / is less than or equal to IQ, and more preferably less than or equal to IQ.

In the present invention, in order to excite and decompose the linear silicon hydride compound of the general formula that is in a gaseous state, a halogen compound (for example, F2 gas, C60, , gasified Br2, I2, etc.), radical generation reactions occur between halogen atoms and 81 and H, excitation and decomposition of silicon compounds,
Therefore, the formation of a deposited film is promoted, which is preferable. Also,
It is expected that halogen will be injected into the deposited film to reduce structural defects, and that dangling Sl will combine with bonds to act as a terminator, resulting in a high-quality silicon film. The halogen to be introduced may be radicalized in advance.

In the present invention, the group forming the silicon-containing deposit is preferably placed under reduced pressure, but the method of the present invention can also be carried out under normal pressure or under pressure. The excitation energy used to excite and decompose a linear silicon hydride compound is limited to light energy, but the cyclic silicon hydride compound of the above general formula can be used to impart relatively low energy such as light energy. It can be easily excited and decomposed to form a high-quality silicon deposited film, and the temperature of the substrate can be kept relatively low. It is applied uniformly or selectively to the raw material that has arrived, but if optical energy is used, it is possible to irradiate the entire substrate using an appropriate optical system to form a deposited film, or It also has the convenience of being able to selectively and controlly irradiate only a desired area to form a deposited film, or to form a deposited film by irradiating only a predetermined graphical area using a resist or the like. Because of this, it can be used advantageously.

In addition, two or more of the linear silicon hydride compounds having the above general formula may be used in combination, but in this case, the film properties expected to be improved by each compound are averaged or synergistically improved. properties obtained.

This will be explained below with reference to the drawings.

The drawing is a schematic diagram showing an example of an apparatus used to form an a-8i deposited film used as a photoconductive film, a semiconductor film, an insulating film, etc. by the method of the present invention.

In the figure, 1 is a deposition chamber, and a desired substrate 3 is placed on a substrate support 2 inside. The base 3 may be conductive, semiconductive, or electrically insulating. Examples of electrically insulating bases include polyester, polyethylene,
Films or sheets of synthetic resins such as polycarnate, cellulose acetate, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, etc.
Glass, ceramic, paper, etc. are commonly used. Moreover, an electrode layer, another silicon layer, etc. may be laminated on the base 3 in advance.

Numeral 4 is a heater for heating the substrate, which is supplied with electricity through a conductor 5 and generates heat. The substrate temperature is not particularly limited, but in carrying out the method of the present invention, it is preferably 50 to 15
The temperature is preferably 0°C, more preferably 100 to 150°C.

Reference numerals 6 to 9 are gas supply sources, and if a liquid one of the linear silicon hydride compounds represented by the above general formula is used, an appropriate vaporizer is provided. The vaporizer may be of any type, such as a type that utilizes heating and boiling, or a type that allows a carrier gas to pass through the liquid raw material. The number of gas supply sources is not limited to four, and the number of linear silicon hydride compounds of the general formula used. When using halogen gas, carrier gas, diluent gas, catalyst gas, etc., they are appropriately selected depending on whether or not they are premixed with the compound of the general formula as the raw material gas. In the figure, to the gas supply sources 6 to 9, a is added to the branch pipe, a b to the flowmeter, and a C to the pressure pipe on the high pressure side of each flowmeter. , d or e are pulps for opening/closing each gas flow and adjusting the flow rate. Raw material gases etc. supplied from each gas supply source are mixed in the middle of the gas introduction pipe 10 and are not shown. It is energized by the exhaust device and introduced into the chamber 1. Reference numeral 11 denotes a pressure gauge for measuring the pressure of gas introduced into the chamber 1. Further, reference numeral 12 is a gas exhaust pipe, which is connected to an exhaust device (not shown) for forcibly exhausting the pressure inside the deposition chamber 1 and the introduced gas.

13 is legator pulp. When the inside of the chamber 1 is evacuated and brought into a reduced pressure state before introducing the raw material gas etc., it is desirable that the atmospheric pressure in the chamber is preferably 5 X 10-5 Torr or less, more preferably I X 10-'Torr or less. . In addition, when raw material gas etc. are introduced,
The pressure inside the chamber 1 is preferably between 1×10 and 100 To
rr, preferably maintained in the range of lXl0 to ITorr.

As an example of an excitation energy supply source used in the present invention,
Reference numeral 14 denotes a light energy generating device, which may be a mercury lamp, a xenon lamp, a carbon dioxide gas lede, an argon ion lede, an excimer laser, or the like. Note that the light energy used in the present invention is not limited to ultraviolet energy, and any wavelength range may be used as long as it can excite and decompose the source gas and deposit decomposition products. Furthermore, this does not exclude the case where light energy is absorbed by the raw material gas or the substrate and converted into thermal energy, and the thermal energy causes excitation and decomposition of the raw material gas to form a deposited film. The light 15 directed from the energy generating device 14 to the entire substrate or a desired part of the substrate using an appropriate optical system is irradiated to the raw material gas etc. flowing in the direction of the arrow 16, causing excitation and decomposition to cause the substrate 3 A deposited film of A-8T is formed on the entire top or a desired portion.

According to the method of the present invention, a deposited film having any thickness from thin to thick can be obtained as desired, and the area of the film can also be selected as desired. The film thickness can be controlled by conventional methods such as controlling the pressure, flow rate, concentration, etc. of the source gas, and controlling the amount of excitation energy. For example, a-81 that constitutes a general photoconductive film, semiconductor film, or insulator film, etc.
When producing a film, the film thickness is preferably 500 to 5×10
'X% is preferably selected in the range of 1000 to 1ooo-X.

Specific examples of the present invention are shown below.

Example 1 As the linear silicon hydride compound of the general formula, 5i4
A Jlla-8t deposited film was formed using H1o and the apparatus shown in the drawing.

First, the polyethylene terephthalate film substrate was placed on the support stand 2, and the inside of the deposition chamber 1 was evacuated using an exhaust device to reduce the pressure to 10-' Torr. At the substrate temperature shown in Table 1, the silicon halide compound in the gaseous state was introduced into the deposition chamber at a flow rate of 1508 CCM, and the halogen gas was introduced at a flow rate of 20 SCCM, and the atmospheric pressure in the chamber was adjusted to 0.1 Torr.
The substrate was irradiated perpendicularly to the substrate with a 100 kW X-lamp while maintaining the temperature at 100 kW to form an I-8I film with a thickness of 5,000×. The film formation rate was 1.3X/IIec.

For comparison, an a-81 film was formed in the same manner using S1□H6. The film formation rate was /X/aec.

Next, each obtained a-81 film sample was placed in a vapor deposition tank, and 1
After pulling down to 0-' Torr, the vacuum level is 10-5 Torr.
After evaporating At at 1500X at a deposition rate of 20L/see to form a comb-shaped U gap electrode (length 250μ, medium 5μ), photocurrent (AM 1.10) was applied at an applied voltage of 10V.
0mW7G++s') and dark current, photoconductivity σp
, taking the ratio σp/σd of σp and dark conductivity σd, a-8
One film was evaluated. The results are shown in the table.

Example 2 As the cyclic silicon hydride compound of the general formula, 814H
,. (8i5H42, 816H, 4 or 8i instead of 0,
An a-81 film was formed in the same manner as in Example 1 except that H16 was used, and σp and σp/ad were determined. From the results shown in Table 0, the a-8t film according to the present invention can obtain good σp and σp/cF d even at low substrate temperatures.

〔Effect of the invention〕

According to the present invention, a high quality silicon deposited film can be formed at a low substrate temperature and at a high film formation rate. Moreover, even when the film to be formed has a wide area and is thick, uniform electrical and optical characteristics can be obtained and quality stability can be ensured, which is an unprecedented and exceptional effect. In addition, there is no need to heat the substrate at high temperatures, which saves energy; it is possible to form a film even on substrates with poor heat resistance; the process can be shortened by low-temperature ripening; and the raw material compounds can be easily synthesized. It is inexpensive, has excellent stability, and has few handling risks.

[Brief explanation of drawings]

The drawing is a schematic diagram showing the J1 structure of the optical energy irradiation type deposited film interaction apparatus used in the present invention. DESCRIPTION OF SYMBOLS 1... Deposition chamber, 2... Substrate support stand, 3... Substrate,
4...Heater, 6-9...Gas supply source, 1o...
- Gas introduction pipe, 12... Gas exhaust pipe, 14... Light energy generator.

Claims (1)

[Claims] A gaseous atmosphere of a linear silicon hydride compound represented by the general formula "nH2n+2 (in the formula, n represents an integer of 4 or more) is formed in a chamber containing a substrate, and light energy is utilized. A method for forming a deposited film, comprising: exciting and decomposing the compound to form a deposited film containing silicon on the substrate.