JPS63164308A - Deposited film formation - Google Patents

Abstract

PURPOSE:To easily form the deposited film having the film structure in which composition and characteristics are differentiated by the direction of film thickness by a method wherein the shifting distance to a substrate in the reaction space of a gaseous raw material substance and a gaseous halogen oxidizing agent are differentiated. CONSTITUTION:The shifting distance to a substrate of the mixed gas of a gaseous raw material substance and a gaseous halogen oxidizing agent is set relatively long when a layer containing a number of Si-H2 coupling is formed while a deposited film is being formed, and said shifting distance is changed relatively short when a layer containing a large number of Si-H2 coupling is going to be formed. To be more precise, the piping to be used for introduction of gas for a deposited film forming device is constructed in a double concentrically arranged structure, and it has the first gas introducing pipe 109 with which gas is introduced from gas cylinders 101, 102, 103, 104 and 105, and also the second gas introducing pipe 110 with which gas is introduced from a gas cylinder 106. A substance 118 can be arranged properly on the position in the desired distance from the position of each gas introducing pipe by vertically moving a substrate holder 112 or the gas introducing pipes 109 and 110.

Description

[Detailed Description of the Invention] [Technical Field to which the Invention Pertains] The present invention relates to a functional film, particularly a functional film that is applied to electronic devices such as semiconductor devices, electrophotographic photoreceptors, and optical sensors for optical image input devices. The present invention relates to a deposited film forming method that is advantageous for producing functional films.

[Prior Art] Conventionally, non-single-crystalline functional films such as amorphous or polycrystalline films such as semiconductor films and insulating films have been deposited using deposition methods that are individually suited to their desired physical properties and applications. ing.

For example, if necessary, amorphous or polycrystalline non-single crystal silicon (rNON -9i (H
,

X)", rpo17- to indicate polycrystalline silicon
3i (H,

It goes without saying that this falls within the category of Generally, the plasma CVD method is widely used and commercialized.

However, the reaction process in this plasma CvD method is very complex, and therefore there are many parameters for forming the deposited film (e.g., substrate temperature, flow rate and ratio of introduced gas, pressure during formation, high frequency power, electrodes, etc.). Since it depends on a combination of many parameters (such as the structure of the reaction vessel, pumping speed, plasma generation method, etc.), it is necessary to select parameters specific to each device. Furthermore, control of each parameter during the formation of a deposited film is also complicated.

As a new deposited film formation method that eliminates these drawbacks of the plasma CVD method and reduces control parameters, it is possible to obtain films with high quality and excellent electrical and optical properties comparable to plasma CVD. A raw material and a gaseous halogen-based oxidizing agent are introduced into a reaction space and brought into contact to generate an excited state precursor, and a deposited film is formed on a substrate using the precursor as a source of deposited film constituent elements. A method for forming a deposited film (hereinafter referred to as a "chemical deposition method") has recently been announced and is attracting attention.

With this chemical deposition method, a film can be deposited simply by bringing a specific gas into contact with it, which simplifies the manufacturing equipment compared to traditional methods, and reduces the number of control parameters, making it easier to control manufacturing conditions. Become. However, the relationship between the control parameters in this chemical deposition method and the properties of the deposited film has not yet been clarified.

[Problems to be Solved by the Invention] The present invention has been made to provide a method for forming a deposited film that can control the film composition or characteristics by controlling the parameters in the above-mentioned chemical deposition method.

[Means for Solving the Problems] The method for forming a deposited film of the present invention comprises a gaseous raw material for forming a deposited film, and a gaseous halogen-based oxidizing agent having the property of oxidizing the raw material. introducing into and contacting the reaction space to produce a plurality of precursors including excited state precursors; and depositing at least one of the precursors on the substrate as a source of a deposited film component. In the deposited film forming method for forming a film, the length of the path from the position where the gaseous raw material for forming the deposited film and the gaseous halogen-based oxidizing agent are brought into contact with each other to the point where the gaseous halogen-based oxidizing agent is introduced onto the substrate is determined during the formation of the deposited film. It is characterized by changing.

According to the deposited film forming method of the present invention described above, it is possible to easily form a deposited film having a film structure having different compositions or characteristics in the film thickness direction, for example.

Next, the circumstances leading to the discovery of the structure of the present invention and its effects will be explained.

The present inventor conducted various experiments in order to elucidate the relationship between the distance traveled by a gaseous mixture of a gaseous raw material and a gaseous halogen-based oxidizing agent to a substrate in a chemical deposition method and the physical properties of a deposited film, and the results were as follows. It has been found that the bonding form of hydrogen in the deposited film is greatly influenced by the distance traveled by the gaseous mixture of the gaseous source material and the gaseous halogen-based oxidizing agent.

For example, in the above-mentioned WON-St (H,
It has an absorption peak near C11, and the 5r-H2 bond is 21
It is known that the hydrogen bond form in the film, which has an absorption peak near 00 cm, has a great influence on the physical properties of the film.
Device containing i-H2 bonds at a certain ratio (Japanese Patent Application Laid-open No. 58
-88380, JP-A-58-152280, etc.) and S
A device in which a layer containing mainly i-H bonds and a layer containing mainly 5i-H2 bonds are stacked
etc.) have been proposed.

The present inventor deposited various films by a chemical deposition method by setting various travel distances of a gas mixture of a gaseous raw material and a gaseous halogen-based oxidizing agent to a substrate, and determined that the infrared light absorption spectra of the deposited films were Ratio of the intensity of the absorption peak near 2000 C and the absorption peak near 2100 C
It has been found that (2000c)/I(2100am), that is, the ratio of 5i-H bonds to Si-[2 bonds in the deposited film, increases as the distance from the gas inlet to the substrate increases.

For example, in the deposited film forming stage shown in FIG.
9, F2 diluted to 10% with He of Pombe 106
Gas was introduced into the reaction chamber 120 from the gas inlet pipe 110 at 150 scctm, and the distance from the gas inlet to the substrate was changed from 30 mm to 80 layers, and the A-S was placed on the substrate 118.
i(H,X) film was deposited. Note that the internal pressure of the reaction chamber is 0,
The temperature of the substrate was kept constant at 3 Torr and 300°C. At this time, the distance from the gas inlet to the substrate and the deposited film I (2
000 cm ) / I (210 Gcm ) is shown in FIG. 2, and it can be seen that the ratio of Si-H bonds to 5i-H2 bonds changes greatly depending on the distance from the gas inlet to the substrate.

That is, in the deposited film forming method of the present invention, the distance traveled by the mixed gas of the gaseous raw material and the gaseous halogen-based oxidant to the substrate is such that a layer containing many 5i-H bonds is formed during the deposited film formation. When trying to form a layer containing many 5i-82 bonds, it is relatively long (and when trying to form a layer containing many 5i-82 bonds, it is changed to be relatively short).

For example, when using the apparatus shown in Fig. 1, the moving distance of the mixed gas of the gaseous raw material and the gaseous halogen-based oxidant in the reaction space to the substrate can be changed by moving the gas inlet pipe. , the substrate may be moved, and the rate of change in distance may be rapid when a rapid change in film properties is required, or slow when a gradual change in film properties is required, depending on the application.

Furthermore, control of the film composition or characteristics by changing the moving distance of the mixture of gaseous raw material and gaseous halogen-based oxidizing agent is applicable not only to non-single-crystal silicon but also to other non-single-crystal materials, such as non-single-crystal silicon. Single crystal germanium A-G e (H,
), non-single crystal silicon germanium A-3iGe (
H,X), non-single crystal silicon carbide A-3iC(H,X)
, non-single crystal fermented silicon A-3iO(H,X), non-single crystal silicon nitride A-3iN(H, This was confirmed by measuring the hydrogen bonding state using infrared absorption spectroscopy.

In the deposited film forming method of the present invention, the gaseous raw material used for forming the deposited film is oxidized by chemical contact with a gaseous halogen-based oxidizing agent, so that the desired deposited film cannot be formed. In the present invention, the above-mentioned gaseous raw material and gaseous halogen-based oxidizing agent are those that are made into a gaseous state upon chemical contact. In normal cases, it may be gas, liquid, or solid.

Ar+He when the raw material for forming the deposited film or the halogen-based oxidizing agent is liquid or solid.

N2. Using a carrier gas such as H2, bubbling is performed while applying heat if necessary, and a raw material for forming a deposited film and a halogen-based oxidizing agent are introduced in gaseous form into the reaction space.

At this time, the partial pressure and mixing ratio of the gaseous raw material and the gaseous halogen-based oxidizing agent can be adjusted by adjusting the flow rate of the carrier gas or the vapor pressure of the raw material and the gaseous halogen-based oxidizing agent during the formation of the deposited film. Set.

As the raw material for forming the deposited film used in the present invention, for example, if a tetrahedral deposited film such as a semiconductor or electrically insulating silicon deposited film or germanium deposited film is to be obtained, a linear deposited film may be used. Effective examples include branched chain silane compounds, cyclic silane compounds, and chain germanium compounds.

Specifically, as the linear silane compound, Stu
(n = i I 213141 s + 6 +
7rn 2n+2 8), as a branched chain silane compound, SiH35i
Examples of H(SiH3)SiH2SiH3 and chain germane compounds include CeH (m=1.2.3°rs 2+s+2 4.5). In addition, for example, if a deposited film of tin is to be produced, tin hydride such as SnH4 can be used as an effective raw material.

Of course, these raw materials can be used not only alone but also as a mixture of two or more.

The halogen-based oxidizing agent used in the present invention is in a gaseous state when introduced into the reaction space, and only comes into chemical contact with the gaseous raw material for forming a deposited film that is simultaneously introduced into the reaction space. It has the property of effectively oxidizing, and halogen gas such as '21 cjL 21''2112 can be cited as an effective gas.

These halogen-based oxidants are in gaseous form, and are introduced into the reaction space together with the gaseous raw material for forming the deposited film at a desired flow rate and supply pressure, and mixed and collided with the raw material. The raw material is brought into chemical contact and oxidized to efficiently generate a plurality of types of precursors including excited state precursors.

Excited state precursors and other precursors are generated.

At least one of them serves as a source of components for the deposited film being formed.

The precursors produced can decompose or react to form another excited state precursor or a precursor in another excited state, or optionally release energy, but can be formed in that form. A deposited film with a three-dimensional network structure is created by touching the surface of the substrate disposed in the film space.

The excited energy level is preferably an energy level that accompanies luminescence in the process of energy transition of the excited state precursor to a lower energy level or change into another chemical species. The deposited film forming process of the present invention proceeds more efficiently and with less energy by forming activated precursors including excited state precursors that emit light during the transition of
A deposited film is formed that is uniform over the front surface of the film and has better physical properties.

In the present invention, the type and type of raw material and halogen-based oxidizing agent are selected as film-forming factors so that the deposited film forming process can proceed smoothly and a film with high quality and desired physical properties can be formed. The combination, the mixing ratio of these, the pressure during mixing, the flow rate, the internal pressure of the film forming space, the gas meteor, the film forming temperature (substrate temperature and atmosphere temperature), and the resistance from the gas inlet to the substrate can be adjusted as desired. be selected as appropriate. These film-forming factors are generally organically related and are not determined independently, but are considered to be determined depending on each other in relation to each other. The ratio of the amount of the gaseous raw material for forming the deposited film and the gaseous halogen-based oxidizing agent is:
Among the above film formation factors, it can be determined as desired in relation to the relevant film formation factors, but the introduction flow rate ratio is preferably l/100 to 100/l, more preferably 1150 to 100/l. A ratio of 50/1 is desirable.

In the present invention, the reaction space in which the gaseous raw material and the gaseous halogen-based oxidizing agent contact to produce the precursor is a reaction space in which the precursor is deposited on the substrate to form a deposited film. It may be separate from the membrane space or may be integrated with it.

The pressure at the time of mixing when introduced into the reaction space is preferably higher in order to increase the probability of chemical contact between the base material and the base halogen-based oxidizing agent, but It is preferable to determine the optimum value as desired by considering the following.The pressure at the time of mixing is determined as described above, but the pressure at the time of each introduction is preferably from ixto atm to 10 atm. , more preferably IX1O
It is desirable that the pressure be between atm and 3 atm.

The pressure in the film-forming space, that is, the pressure in the space where the substrate on which the film is to be formed is disposed, is the pressure of the excited state precursor (E) generated in the reaction space and, if necessary, the precursor. The precursor (CD) derived from the precursor (E) is appropriately set as desired so as to effectively contribute to film formation.

When the film forming space is open and continuous with the reaction space, the internal pressure of the film forming space is the pressure introduced into the reaction space between the substrate-like raw material for forming the deposited film and the gaseous halogen oxidant. In relation to the flow rate, adjustment can be made by using, for example, differential exhaust or a large exhaust device.

Alternatively, if the funductance of the connection between the reaction space and the film-forming space is small, an appropriate exhaust system may be provided in the film-forming space.
By controlling the exhaust volume of the device, the pressure in the film forming space can be adjusted.

In addition, if the reaction space and film-forming space are integrated and the reaction position and film-forming position are only spatially different, use differential pumping as described above or use a large-scale pump with sufficient exhaust capacity. It is best to install an exhaust system.

As described above, the pressure in the film forming space is determined based on the relationship between the gaseous raw material introduced into the reaction space and the introduction pressure of the gaseous halogen-based oxidizing agent, but is preferably 0.0
01 Torr to 100 Tarr, more preferably 0.01 Torr to 30 Torr, optimally 0.0
It is desirable that the pressure be 5 to 10 Torr.

Regarding the gas meteor, when the raw material for forming the deposited film and the halogen-based oxidizing agent are introduced into the reaction space, they are mixed uniformly and efficiently, and the precursor (E) is efficiently generated. It is necessary to take into consideration the geometrical arrangement of the gas inlet, the substrate, and the gas outlet when designing so that the film can be formed properly without any trouble. One preferred example of this geometry is shown in FIG.

The substrate temperature (Ts) during film formation is set as desired depending on the type of gas used, the type of deposited film to be formed, and the required characteristics. When forming a silicon deposited film with better properties such as semiconductor properties and photoconductivity, the temperature is preferably room temperature to 450°C, more preferably 50 to 400°C. Substrate temperature (Ts) is 70-350℃
In addition, when obtaining a polycrystalline film, the temperature is preferably 200 to 650°C, more preferably 30°C.
The temperature is preferably 0 to 600°C.

The atmospheric temperature (Tat) in the film forming space is set such that the precursor (E) and the precursor (D) to be produced do not change into chemical species unsuitable for film formation, and the precursor (E) is efficiently heated. ) is determined as appropriate in relation to the substrate temperature (Ts) as desired.

The substrate used in the present invention includes the deposit formed! It may be electrically conductive or electrically insulating as long as it is selected as desired depending on the use of J.
Examples of the conductive substrate include:

NiCr, stainless steel, A1. Cr, No,
Au, Ir, Nb, Ta, V, Ti, Pt
, Pd, or alloys thereof.

As the electrically insulating substrate, films or sheets of synthetic resins such as polyester, polyethylene, polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, glass, ceramic, paper, etc. are usually used. Ru. Preferably, at least one surface of these electrically insulating substrates is subjected to a conductive treatment, and another layer is preferably provided on the conductive treated surface side.

For example, if it is glass, its surface may be NiCr, AI,
Cr, No, Au, Ir, Nb, Ta,
V, Ti, Pt, Pd, In203,
Sn02, ITO(In203+Sn02
), or if it is a synthetic resin film such as polyester film, Ni
Cr, AI, Ag, Pb, Zn, Xi,
Au, Cr, No, Ir,
Nb, Dina, V, Ti, Pt
The surface is subjected to conductive treatment by vacuum evaporation, electron beam evaporation, sputtering, etc., or by laminating with the metal. The shape of the support may be any shape such as a bicylindrical shape, a belt shape, a plate shape, etc., and the shape is determined depending on the need.

It is preferable to select the substrate from among the above in consideration of the adhesion and reactivity between the substrate and the film. Furthermore, if the difference in thermal expansion between the two is large, a large amount of distortion will occur in the film, making it difficult to obtain a high-quality film. Therefore, it is preferable to select and use a substrate whose thermal expansion difference is close to that of the two substrates.

In addition, the surface condition of the substrate is directly related to the structure (orientation) of the film and the occurrence of cone-shaped structures, so it is important to treat the surface of the substrate so that it has a film structure and structure that provides the desired characteristics. is desirable.

FIG. 1 shows an example of an apparatus suitable for implementing the method for forming a deposit HtW1 of the present invention.

The deposited film forming apparatus shown in FIG. 1 is roughly divided into three parts: an apparatus main body, an exhaust system, and a gas supply system.

The main body of the apparatus is provided with one reaction space and a film forming space.

101 to 106 are cylinders filled with gas used in film formation, 101a to 106a are gas supply pipes, and 101b to 106b are mass flow controllers 5- for adjusting the flow rate of gas from each cylinder. ．． 101
c~106C are gas pressure gauges, 101d~106 respectively
d and 101e-106e are valves, 101f-1
06f is a pressure gauge that indicates the pressure inside the corresponding gas cylinder.

Reference numeral 120 denotes a vacuum chamber, which has a structure in which a pipe for introducing gas is provided at the upper part and a reaction space is formed downstream of the pipe.
It has a structure in which a film forming space is formed in which a substrate holder 112 is provided such that a substrate holder 18 is installed therein. The gas introduction pipes have a double concentric arrangement structure, and include a first gas introduction pipe 109 through which gas from gas cylinders 101, 102, 103, 104, and 105 is introduced, and a gas cylinder lO.
It has a second gas introduction pipe 110 into which six gases are introduced.

Gas is supplied from the tube cylinder to each introduction pipe through gas supply pipelines 123 and 124, respectively.

Each gas introduction pipe, each gas supply pipeline, and the vacuum chamber 120 are evacuated via the main vacuum valve 119 by a vacuum evacuation device (not shown).

The base body 118 is the base body holder 112 or the gas introduction pipe 109
, 110 up and down, it is placed at a desired distance from the position of each gas introduction pipe.

In the case of the present invention, the distance between the substrate and the gas inlet of the gas inlet tube is determined appropriately by taking into account the type of deposited film to be formed, its desired characteristics, gas flow rate, internal pressure of the vacuum chamber, etc. However, it is preferably several inches to 20 centimeters, more preferably 5 mm to
It is desirable that it be about 15c■.

113 heats the base 118 to an appropriate temperature during film formation, or preheats the base 11g before film formation,
Furthermore, it is a substrate heating heater that heats the film to 7 anneal the film after film formation.

The base heater 113 is connected to the power source 11 by a conductor 114.
Power is supplied by 5.

116 is a thermocouple for measuring the substrate temperature (Ts), and is electrically connected to the temperature display device 117.

〔Example〕

The present invention will be specifically described below with reference to Examples.

Example 1 A deposited film was produced by the method of the present invention in the following manner using the deposited film forming apparatus shown in FIG.

The SiH gas filled in the cylinder 101 has a flow rate of 15
F2 gas diluted to 10% with He filled in the cylinder 106 (hereinafter F2 gas
2/H2 gas) was introduced into the vacuum chamber 120 from the gas introduction pipe 110 at a flow rate of 15° and 5 ccs.

At this time, the pressure inside the vacuum chamber 120 was adjusted to 0.3 Tarr by adjusting the opening/closing degree of the vacuum valve 119. A Si wafer (1 inch in diameter) was used as the substrate, and the substrate temperature was 3.
The temperature was set at 00°C. The distance between the gas inlet and the base is 40m
m, and film formation was performed for 20 minutes in this state. After 20 minutes, the gas inlet tube was moved to change the distance between the gas inlet and the substrate, and open film formation was continued for another 60 minutes.
A Si:H:F film with a thickness of zm was deposited. 2000c
Si
The average value of the ratio of H bonds to SiH2 bonds for all layers was found to be SiH/SiH2 = 3.1. This is a film prepared by fixing the distance from the gas inlet to the substrate at 40mm (SiH/SiH2 = 1, deposition rate 7A/sec),
The film was fixed at 80 mm (SiH/SiH2=
8, a deposition rate of 117 seconds), which was calculated from the data.

In addition, the ratio of the time to form a film in a 40 m layer and the time to form a film in an 80 m layer from the gas inlet to the substrate is 1/10.

Deposited films were prepared in the same manner with 1/1, 3/1, and 10/1, and their infrared absorption ratios were examined. All deposited films had a relatively large number of SiH2 bonds (SiH/SiH2
=1) layer and 5il (mainly bonded (SiH/SiH2=
8) It was confirmed that it had a laminated structure of layers.

Example 2 An electrophotographic photoreceptor was produced as an example of a functional deposited film by the method of the present invention. Set the A1 substrate (15cs x 15c layer) in the film forming apparatus shown in FIG.
; iH4 gas, pombe 102 c7) Ge) I a gas, CH4 gas in pombe 103, F 2 in pombe 106
Using B2H6 gas (hereinafter abbreviated as B2H6/He gas) diluted to 1,000 pp with He from Pombe 105, under the conditions shown in Table 1, while changing the distance from the gas inlet to the substrate. A deposited film having a four-layer structure was formed.

The obtained deposited film was uniformly corona charged at +6 kV, and 1
After exposure to pattern light of lux*sec, cascade development of the electrostatic latent image was performed using a two-component developer, and a clear toner image was obtained.

〔Effect of the invention〕

As is clear from the description of the above embodiments, according to the deposited film forming method of the present invention, by changing the moving distance of the gaseous raw material and the gaseous halogen-based oxidizing agent to the substrate in the reaction space, It is possible to easily form a deposited film with a film structure that differs in composition and properties in the film thickness direction, etc.
The film composition and properties can be freely controlled.

[Brief explanation of the drawing]

FIG. 1 is a schematic structural explanatory diagram showing one example of an apparatus suitable for implementing the deposited film forming method of the present invention. FIG. 2 is a curve diagram showing the relationship between the moving distance of gaseous raw materials and the composition of the deposited film formed when the method of the present invention is carried out, and the horizontal axis is from the gas inlet to the substrate. distance (ms+), the vertical axis is the 5i-H bond (
2000 cm), and 5i-H2 bond (2100 cm
Ratio of absorption peak intensity to 1 (near 2000 cm)
)/I (2100c+++). 101-106... Gas cylinder, 109... First gas introduction pipe, 110... Second gas introduction pipe, 118... Substrate.

Claims (1)

[Claims] (1) A precursor in an excited state is created by introducing a gaseous raw material for forming a deposited film and a gaseous halogen-based oxidizing agent having the property of oxidizing the raw material into a reaction space and bringing them into contact with each other. A deposited film forming method in which a plurality of precursors including: A method for forming a deposited film, characterized in that the length of a path from a position where a gaseous raw material and a gaseous halogen-based oxidizing agent are brought into contact with each other until the gaseous halogen-based oxidizing agent is guided onto the substrate is changed during the formation of the deposited film.