JPS6190416A - Formation of deposited film - Google Patents

Abstract

PURPOSE:To form the high-quality silicon deposited film while ensuring the uniform electrical and optical characteristics and the stability of quality by increasing a film forming velocity by applying an alternate magnetic field to the inside of the chamber containing a substrate so as to excite a hydrogenated silicon compound by utilizing a light energy and to decompose or polymerize it. CONSTITUTION:In the chamber containing a substrate, a gas state atmosphere of a hydrogentated silicon compound expressed by a general formula Sin Hm (n is an integer of 1 or more and m is that 2 or more) is formed as a material. The light 15 directed to the substrate from a light energy generator 14 is projected to a material gas or the like and causes excitation and decomposition or polymerization thereby forming a deposited film of a-Si on the base 3. A coil 17 for generating an alternate magnetic field inside a deposition chamber 1 can promote a radical reaction velocity by changing a frequency and an amplitude of the alternate current. Also the radical reaction can be made uniform by the alternate magnetic field and the control of film thickness can be attained by the control of the pressure, flow, and concentration of the material gas and the control of a quantity of excited energy. Thus the film forming velocity can be improved while maintaining a high quality of the deposited film.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a conjunctive film containing silicon, particularly amorphous silicon (hereinafter referred to as a-9i) useful as a photoconductive film, a semiconductor film, an insulator nrJ, etc. ) or a method suitable for forming a deposited film of polycrystalline silicon or the like.

[Prior Art] Conventionally, glow discharge deposition method or thermal energy deposition method is known as a method for forming a deposited film using, for example, SiH4 or Si2 H6 as a raw material. That is, SiH
In this method, 4 or Si2 H@ is excited using electrical energy or thermal energy, and decomposed or polymerized to form a deposited film of a, -9i on the substrate. Additionally, this membrane is used for various purposes.

However, when these SiH4 or Si2 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, making it difficult to control to achieve stable and reproducible conditions. becomes. This is particularly noticeable when forming a thick deposited film over a wide area.

In addition, the thermal energy deposition method also requires high temperatures, which limits the types of substrates that can be used and increases the probability that useful bonded hydrogen atoms in a-Si will dissociate due to high temperatures. , it becomes difficult to obtain the desired characteristics.

In this way, when forming a deposited film using Sin4 or Si2H6, it is difficult to ensure uniform electrical and optical properties and quality stability, and the film surface is disturbed during deposition and defects in the bulk occur. At present, there are still problems that need to be resolved, such as the tendency for problems to occur.

Therefore, in recent years, in order to solve these problems, SiH4
Alternatively, an a-9i optical energy deposition method (photo-CVD method) using Si2H6 as a raw material has been proposed and is attracting attention. According to this optical energy deposition method, the above-mentioned problems can be significantly improved due to the advantage that the a-9i deposited film can be produced at a low temperature.

However, with the optical energy deposition method using SiH4 or Sr2 H6 as a raw material under relatively small excitation energy such as optical energy, dramatically efficient decomposition cannot be expected, so an improvement in the film formation rate cannot be expected. figure,
A new problem has arisen in that mass production is difficult.

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

[Objective of the Invention] The object of the present invention is to increase the film formation rate while maintaining high quality, and to ensure uniform electrical and optical characteristics and quality stability even in the case of a wide area and thick film. An object of the present invention is to provide a method for forming a deposited film that can produce a high quality silicon deposited film while maintaining the same quality.

[Summary of the invention] In a chamber containing a substrate, the general formula Sin Hm (wherein,
n is an integer of 1 or more, and m is an integer of 2 or more. ) in which a silicon-containing deposited film is formed on the substrate by forming a gaseous atmosphere of a silicon hydride compound and exciting the compound to decompose or polymerize the compound; The method is characterized in that the compound is excited and decomposed or polymerized by applying an alternating magnetic field to the compound and using light energy.

[Example] Hereinafter, embodiments of the present invention will be described mainly in the case of an a-9i deposited film.

First, in the present invention, in order to excite, decompose or polymerize the silicon hydride compound of the general formula in the gaseous state, the hydrogen and halogen compounds (
For example, F2 gas, C12 gas, gasified Br2. I
It is desirable to introduce St.
A radical generation reaction occurs between the H1/\rogen atom and Si and H, and the excitation/decomposition or polymerization of the silicon compound,
This is because the formation of a deposited film is therefore promoted. In addition, halogen is incorporated into the deposited film that is formed, causing defects in the structure.
11111t%, and is expected to combine with the 9i dangling bond to function as a terminator, resulting in a high quality silicon film. The norogen to be introduced may be radicalized in advance.

Note that the chamber in which the deposited film containing silicon is formed is
Although it is preferable to use the method under reduced pressure, the method of the present invention can also be carried out under normal pressure or increased pressure.

In the present invention, the excitation energy used to excite and decompose the silicon hydride compound of the general formula is limited to light energy. However, if light energy is used, gas can be generated using an appropriate optical system. A deposited film can be formed by irradiating the entire area, or a deposited film can be formed partially by irradiating only a desired part in a selective and controlled manner.
Further, it is advantageously used because it has the convenience of being able to form a deposited film by irradiating only a predetermined graphical portion using a resist or the like.

In addition, two or more types of silicon hydride compounds having the above general formula may be used in combination, but in this case, the expected film properties of each compound will be averaged or synergistically improved. You can get

Hereinafter, one embodiment of the present invention will be described in detail using the drawings.

The drawing is a schematic configuration diagram showing an example of a light energy irradiation type deposited film forming apparatus for use in an embodiment of the method of the present invention.

In the figure, reference numeral 1 denotes a deposition chamber f, in which a desired substrate 3 is placed on a substrate support 2. The substrate 3 may be conductive, semiconductive, or electrically insulating. For example, electrically insulating substrates include polyester, polyethylene, polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride, polyvinylidene chloride, Films or sheets of synthetic resins such as polystyrene and polyamide, glass, ceramics, paper, etc. are commonly used. Also,
The base body 3 may be provided with an electrode layer, another silicon layer, etc. in advance.

Reference numeral 4 denotes a heater for heating the substrate, which is supplied with electricity via a conductive wire 5 and generates heat. Although the substrate temperature is not particularly limited, in carrying out the method of the present invention, it is preferably 50 to 150℃.
℃, more preferably 10G-15000.

6 to 9 are gas supply sources, and if a liquid silicon hydride compound represented by the above general formula is used, an appropriate vaporizer is provided.

There are two types of vaporizers, such as a type that uses heating and boiling, and a type that allows a carrier gas to pass through the liquid raw material. When using silicon hydride compounds, halogen gas, carrier gas, diluent gas, catalyst gas, etc.

The gas supply sources 6 to 9 are appropriately selected depending on the presence or absence of premixing with the compound of the general formula that is the raw material gas. 1 is a flowmeter, C is a pressure gauge that measures the pressure on the high pressure side of each flowmeter, and d or e is a valve for opening/closing each gas flow and adjusting the flow rate.

Raw material gases and the like supplied from each gas supply source are mixed in the middle of the gas introduction pipe 10, energized by a ventilation device (not shown), and introduced into the chamber l. 11 is a pressure gauge for measuring the pressure of the gas introduced into the chamber l. Also, 12
is a gas exhaust pipe, which reduces the pressure inside the deposition chamber 1 and forcibly exhausts the introduced gas. J, big 42. Yo 0.
A6. ...l13 is a regulator valve. Before introducing raw material gas etc., exhaust the inside of chamber 1,
In the case of reduced pressure, the atmospheric pressure in the room is preferably 5
10-5 Torr or less, more preferably lXl0-6
It is as follows. In addition, when raw material gas etc. are introduced,
The pressure in chamber 1 is preferably between I x 10' and 100
Torr.

More preferably, I x 10-2 to l Torr.

As an example of the excitation energy supply source used in the present invention, 1
4 is a light energy generator, such as a mercury lamp,
A xenon lamp, carbon dioxide laser, argon ion laser, excimer laser, etc. are used. It should be noted that the light energy used in the present invention is not limited to ultraviolet energy, and the wavelength range does not matter as long as it can excite the source gas, cause φ decomposition or polymerization 1, and deposit the decomposition products. It also excludes cases where light energy is absorbed by the source gas or the substrate and converted into thermal energy, and the thermal energy causes excitation, decomposition, or polymerization of the source gas and forms a deposited film. do not have. The light 15 directed from the light energy generator 14 to the entire substrate or a desired part of the substrate using an appropriate optical system is irradiated to the raw material gas flowing in the direction of the arrow 1B, causing excitation, decomposition, or polymerization. a- on the whole or desired part of the base 3.
A deposited film of Si is formed.

17 is a coil for generating an alternating magnetic field inside the deposition chamber l. By appropriately changing the frequency and amplitude of the alternating current flowing through the coil 17, the reaction rate of the radical reaction can be accelerated. It is assumed that this phenomenon is caused by a group of reactive radicals with a certain degree of polarization being given energy by an alternating magnetic field and exhibiting a kind of energy resonance state in the reaction process between the radicals, which accelerates the reaction rate. be done. It is also presumed that the alternating magnetic field spatially homogenizes the radical reaction.

In this way, a deposited film of any thickness from a thin film to a thick film can be obtained, and the film area can also be arbitrarily selected as desired. The film thickness can be controlled by conventional methods such as controlling the pressure, flow rate, concentration, etc. of raw material gas, and controlling excitation energy. When producing the constituent a-9illI, the film thickness is preferably 500 to 50,000, more preferably 1,000 to 10,000.

Specific examples of the present invention will be shown below.

As the silicon hydride compound of the general formula, chain SiH
3SiH (SiH3) Using SiH3, an a-8i deposited film was formed using the apparatus shown in the drawing.

First, place the polyethylene terephthalate film on support stand 2.
The inside of the deposition chamber was evacuated using a ventilation device, and
The pressure was reduced to O-6 Tart, the temperature was kept at 80°C, and the silicon halide compound in the base state was heated at a flow rate of 1509 CCM and the halogen gas was heated at a flow rate of 209 CCH into the deposition chamber 1 without applying an alternating magnetic field. A 1kW Xe lamp was used to vertically irradiate the room with a 1kW Xe lamp while maintaining the indoor air pressure at 0.1 Tarr.
A film was formed. The film formation rate was 35 people/SeC.

For comparison, a-
A 9i film was formed. The film deposition rate at that time was 15 people/sec.
Met. - On the other hand, under the same conditions, an alternating current of 100 Hz was applied to the coil 17, and the effective value at the center of the deposition chamber 1 was approximately 40 Hz.
When a type I a-9i film was similarly formed while applying an alternating current magnetic field of 0 Gauss, the film formation rate was as low as that of SiH3S.
iH (SiH3) In SiH3 and Si2 H6,
They were 40 people/sec and 18 people/sec, respectively, which was an increase of about 10 to 20% compared to the case without an alternating magnetic field.

Subsequently, each of the a-3i film samples obtained in this way was placed in a vapor deposition tank, the pressure was reduced to 10" Torr, and then the vacuum level was reduced to 1.
Aluminum was evaporated by 1500 people at a deposition rate of 20 people/sec at 0''5 Torr to form a comb-shaped aluminum gap electrode (length 250 m, width 5 mm), and then a photocurrent (AMI , 100aW/cm2)
Measure the dark current and photoconductivity σp, σp (Ω・Cm)
The a-9i film was evaluated by determining the ratio σp/σd between ” and the dark current σd. The results are shown in Tables 1 and 2.

As shown in Tables 1 and 2, the photoconductivity and dark conductivity of the obtained film were constant regardless of the presence or absence of an alternating magnetic field. Furthermore, the film obtained by photo-CVN is plasma Cvn.
Unlike the membranes obtained by vD, 5taebled-
It is known that the Wronski effect is almost nonexistent, but even in optical CvD with an applied alternating magnetic field, the
No taebled-Wronski effect was observed. The silicon-containing deposited film formed by the method of the present invention may be crystalline or amorphous, and the bonding of silicon in the film may be in any form from oligomers to polymers. Furthermore, hydrogen atoms, halogen atoms, etc. in the raw materials may be incorporated into the structure.

Furthermore, the present invention is not limited to the above-mentioned embodiments, and as long as a desired alternating current magnetic field can be applied to the interior of the deposition chamber, the arrangement or number of coils can be changed as appropriate.

[Effects of the Invention] As explained in detail above, the method for forming a deposited film according to the present invention improves the deposition rate while maintaining the quality of the deposited film at a high level by using an alternating magnetic field in combination with photo-CVD. I can do it.

[Brief explanation of drawings]

The accompanying drawing is a schematic configuration diagram showing an example of a light energy irradiation type deposited film forming apparatus for realizing an embodiment of the deposited film forming method according to the present invention. l...Deposition chamber 2φ...Substrate support 3...Substrate 4...Heaters 6 to 9...Gas supply source 10--Fist gas introduction pipe 12...Gas exhaust pipe 14...
・Light energy generator 17...Φ coil

Claims (1)

[Claims] (1) A gaseous atmosphere of a silicon hydride compound represented by the general formula SinHm (where n is an integer of 1 or more and m is an integer of 2 or more) is formed in a chamber containing the substrate, and the compound In the deposited film forming method of forming a deposited film containing silicon on the substrate by exciting and decomposing or polymerizing the A method for forming a deposited film, characterized in that the compound is excited and decomposed or polymerized.