JPS62156270A - Deposited film forming device - Google Patents

Abstract

PURPOSE:To make film forming speed higher and film quality better by blowing the precursors formed by blowing raw materials and halogen oxidizing agents out of a prescribed gas blow port onto a base body. CONSTITUTION:The gaseous raw materials 101, 102 for forming a deposited film and the gaseous halogen oxidizing agents 103-105 for oxidizing said materials are blown out of the blow pipe 111 having a space where both gases 101-105 meet. Such gases 101-105 are introduced into a reaction space where the gases are brought into chemical contact with each other and the precursors including the precursors in the excited state are formed. >=1 kinds of the precursors among such precursors are then blown onto the base body 118 existing in a vacuum vessel 120 from the pipe 111 by which the deposited film is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to functional films, particularly for electronic devices such as semiconductor devices, photosensitive devices for electrophotography, and optical input sensor devices for optical image input devices. The present invention relates to a deposited film forming apparatus used for forming a functional deposited film useful for various applications.

[Conventional technology]

Conventionally, amorphous or polycrystalline functional films such as semiconductor films, insulating films, photoconductive films, magnetic films, or metal films have been formed by forming films that are individually suited from the viewpoint of desired physical properties and applications. method has been adopted.

For example, if necessary, amorphous or polycrystalline non-single crystal silicon (hereinafter [N ON -8i(H, J
In particular, it is abbreviated as "A-8i (H,X) J" when it refers to amorphous silicon, and [poly -8i (H.

Vacuum is used to form silicon deposits such as `` Deposition method, plasma CVD method, thermal CVD method, reactive sputtering method,
Ion blating method, photo-CVD method, etc. have been tried, but in general, plasma CVD method is widely used.
It has been corporatized.

[Problem that the invention seeks to solve]

Hyakunen et al. said that the reaction process in forming silicon deposited films by the conventionally popular plasma CVD method is more complex than that of the conventional CVD method, and there are still many unknowns about the reaction mechanism. do not have. In addition, there are many formation parameters for the deposited film (e.g. substrate humidity, flow rate and ratio of introduced gas, pressure during formation, high frequency power, electrode structure, reaction vessel structure, pumping speed, plasma generation method, etc.). Due to the combination of many parameters, the plasma sometimes becomes unstable, which often has a significant adverse effect on the deposited film formed. Moreover, device-specific parameters must be selected for each device.
Therefore, the reality is that it is difficult to generalize the manufacturing conditions.

On the other hand, in order to develop a silicon deposited film that satisfies the electrical and optical characteristics for each application, it is currently considered best to form it by plasma CVD.

However, depending on the application of silicon deposited films, plasma CV
Forming a silicon deposited film using the D method requires a large amount of equipment investment for mass production equipment, and the management items for mass production are also complicated, the tolerance range for management is narrow, and the adjustment of the equipment is delicate. , these have been pointed out as problems that should be improved in the future.

In addition, in the case of plasma CVD method, since plasma is directly generated by high frequency waves or microwaves in the film forming space where the substrate to be film is placed, the generated electrons and many ion species are This causes damage to the film during the film formation process, causing deterioration of film quality and non-uniformity of film quality.

An indirect plasma CVD method has been proposed as an improvement on this point.

The indirect plasma CVD method generates plasma using microwaves or the like at an upstream location away from the film-forming space, and transports the plasma to the film-forming space to selectively use chemical species that are effective for film-forming. It was planned to be possible.

However, since the plasma CVD method also requires plasma transport, the lifetime of the chemical species effective for film formation must be long, which naturally limits the types of gases that can be used.
These problems include the inability to obtain various deposited films, the large amount of energy required to generate plasma, and the fact that the generation and amount of chemical species effective for film formation cannot be easily controlled. The problems are stacked.

Compared to the plasma CVD method, the photo-CVD method is advantageous in that it does not generate ion species or electrons that damage film formation and film quality, but it does not have as many types of light sources, and the light source wavelength For industrial use, a large light source and its power source are required; and because the window that introduces the light from the light source into the deposition space is covered with a film during deposition, the amount of light decreases during deposition. There is a problem in that the light from the light source is no longer incident on the film forming space.

As mentioned above, there are still many issues to be solved regarding the formation of silicon deposited films, and it is important to mass-produce them using low-cost equipment that saves energy while maintaining its practical properties and uniformity. There is a great desire to develop a method of forming the material. These problems can be cited as similar problems to be solved in other functional films, such as silicon nitride films, silicon carbide films, and silicon oxide films.

[Object] The object of the present invention is to eliminate the drawbacks of the above-mentioned deposited film forming method and at the same time provide a novel deposited film forming apparatus that does not rely on conventional forming methods.

Another object of the present invention is to provide a deposited film forming apparatus that saves energy, allows easy control of film quality, and provides a deposited film with uniform characteristics over a large area.

Still another object of the present invention is to provide a deposited film forming apparatus that is highly productive and mass-producible, and that can easily produce films of high quality and excellent physical properties such as electrical, optical, and semiconductor properties. be.

[Means for solving problems]

A deposited film forming apparatus of the present invention that achieves the above object introduces into a reaction space a gaseous raw material for deposited film formation and a gaseous halogen-based oxidizing agent having the property of oxidizing the raw material. In an apparatus for generating a precursor in an excited state by chemically contacting the precursor, and forming a deposited film on a substrate in a deposition space using the precursor as a source of deposited film components, It is characterized by having a mechanism for blowing out gas from a gas outlet having an intervening space for both gases.

[Effect]

According to the above-described deposited film forming apparatus of the present invention, it is possible to achieve sufficient uniformity of film thickness and film quality at the same time as saving energy, simplifying management and mass production, and requiring a large amount of equipment and resources for mass production equipment. In addition, the control items for mass production become clear, the control tolerance is wide, and equipment adjustment becomes easy.

In the deposited film forming apparatus of the present invention, the gaseous raw material for forming the deposited film used is oxidized by chemical contact with the gaseous halogen-based oxidizing agent, and the target deposited film is In the present invention, the above-mentioned gaseous raw material and gaseous halogen-based oxidizing agent may be selected as desired depending on the type, characteristics, use, etc. In normal cases,
It can be a gas, liquid, or solid.

When the raw material for forming the deposited film or the halogen-based oxidizing agent is liquid or solid, use a carrier gas such as A, He1N2, I2, etc., and perform bubbling while adding heat if necessary. Then, 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 for forming the deposited film and the gaseous halogen-based oxidizing agent. 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, linear Effective examples include linear and branched chain silane compounds, cyclic silane compounds, and chain germanium compounds.

Specifically, as a linear silane compound, S 1 nH
2n+2 (m=t 12131415161718)
, as the branched chain silane compound, 5iHaSiH
(S 1Ha) S 1H2s iH3, as a chain germane compound, GemI2m+2 (m=1.2.3
．． 4.5) etc. 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 is simultaneously introduced into the reaction space through chemical contact with the gaseous raw material for forming a deposited film. It has the property of effectively oxidizing, and F
Effective examples include halogen gases such as 2, (:'j2, Br2, and I2), nascent fluorine, chlorine, and bromine.

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. The excited precursors and other precursors produced serve as a source of components of the deposited film in which at least one of them is formed.

The precursors produced may decompose or react to become other excited precursors or precursors in another excited state, or may be formed in that form, though releasing energy if necessary. A deposited film with a three-dimensional network structure is created by touching the surface of the substrate disposed in the film space.

As the energy level to be excited, the excited state precursor is energy to a lower energy level? In the process of transferring or changing into another chemical species, it is preferable that the energy level is accompanied by light. By forming activated precursors including excited state precursors that are accompanied by light emission due to such energy transition, the axillary formation process of the present invention progresses more efficiently and with more energy savings, A deposited film is formed that is uniform throughout 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 thereof, the pressure during mixing, the flow rate, the internal pressure of the film forming space, the original gas, and the film forming temperature (substrate temperature and ambient temperature) are appropriately selected as desired. These film-forming factors are organically related and are not determined independently, but are determined depending on each other in relation to each other. In the present invention, the ratio of the amounts of the gaseous raw material for forming a deposited film and the gaseous halogen-based oxidizing agent introduced into the reaction space is determined depending on the relationship with the relevant film-forming factors among the above-mentioned film-forming factors. The introduction flow rate ratio can be determined as desired, but preferably,
1/20 to 100/1 is suitable, preferably 1/20 to 100/1.
It is desirable that the ratio be 15 to 50/1.

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 gaseous raw material and the gaseous halogen-based oxidant, but If the pressure in the space is too high, the precursors produced in the chemical contact will collide with other precursors or gaseous source materials, causing secondary reactions in the gas phase and causing the polypropylene to form before reaching the substrate. Melization occurs and becomes a polymer, which no longer contributes to film deposition. Furthermore, the quality of films formed using partially polymerized precursors is poor. Therefore, the pressure within the film forming space cannot be made too high, and therefore there is a limit to the amount of precursor produced through chemical contact. Therefore, in the present invention,
By narrowing the gas outlet, the pressure in the gas outlet tube can be kept high and the pressure in the reaction chamber can be kept low, making it possible to form a high-density, high-quality film. The pressure inside the gas outlet pipe is determined by the size of the gas outlet and the gas flow, but it increases the chemical contact between the gaseous source material and the gaseous halogen-based oxidant, and facilitates the creation of the precursor. In order to do it efficiently, it is usually necessary to
Q torr or more, more preferably 100 torr or more. In this way, narrow the gas outlet,
By increasing the pressure inside the blow-off tube, the raw material for forming the deposited film and the halogen-based oxidizing agent are mixed uniformly and efficiently, and the precursor (1) is efficiently produced.

However, after mixing both gases, in order to cause a sufficient reaction and to efficiently generate precursor 0, it is necessary to hold the gases at a high pressure place in the blow-off pipe for a certain period of time (this time is required for the raw material and the halogen-based oxidant (varies depending on the flow rate). Therefore, it is necessary to provide an intervening space after the introduction tubes for both gases, and then blow out the precursor through the hole in the blowout tube.

It is more desirable that the pressure in the film forming space be low in order to prevent reaction of the precursor produced in the blow-off tube in the gas phase and to prevent contamination with impurities. Usually less than 1 torr,
The substrate temperature (Ts) during film formation is preferably set to 0.1 torr or less as desired depending on the type of gas used, the number of types of deposited films to be formed, and the required characteristics. However, in order to obtain an amorphous film, it is desirable that the temperature is preferably between room temperature and 450°C, more preferably between 50 and 400°C. In particular, when forming a deposited silicon film with better properties such as semiconductor properties and photoconductivity, it is desirable that the substrate temperature (Ts) be 70 to 350°C. When obtaining a polycrystalline film, the temperature is preferably 200 to 650°C, more preferably 300°C.
~a o o ”c is preferable.

The atmospheric temperature (Tat) in the film forming space is set so that the precursor (1) and the precursor (0) that are generated do not change into chemical species unsuitable for film formation, and the precursor (2) is efficiently generated. It can be determined as desired in relation to the substrate temperature (Ts).

The substrate used in the present invention may be electrically conductive or electrically insulating, as long as it is appropriately selected depending on the intended use of the deposited film to be formed. As the conductive substrate, for example, NiCr.

Stainless steel, Ai, Cr, MoXAuXI r, N
b, Ta.

Examples include metals such as VXTi and Pt5Pd, and 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. 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 is NiCr.

A1, Cr, MO% Au, Ir, Nb, T
as V, Tt, Pt.

Pd, InzOa, 8n02, ITO (In203+5
NiCr, Aj, Ag, PbXZnXNiXAu if conductive treatment is performed by providing a thin film such as nOz) or a synthetic resin film such as polyester film.

cr, Mo, Ir, Nb, Ta, V, Ti
, Pt or the like by vacuum evaporation, electron beam evaporation, sputtering, or the like, or by laminating with the metal, and the surface thereof is subjected to conductive treatment. The shape of the support is
It can be of any shape, such as cylindrical, belt-like, plate-like, etc., and the shape is determined according to desire.

The substrate is preferably selected from the above in consideration of the adhesion and reactivity between the substrate and the membrane. Furthermore, if the difference in thermal expansion between the two is large, a large amount of distortion will occur in the film, and a high-quality film may not be obtained, so select and use a substrate with a close difference in thermal expansion between the two. is preferable.

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.

The deposited film forming apparatus of the present invention will be described below with reference to Examples.

〔Example〕

FIG. 1 shows an example of the deposited film forming apparatus 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 apparatus main body is provided with a reaction space and a film forming space.

Reference numerals 101 to 105 are cylinders filled with gas used in film formation, 101a to 105a are gas supply pipes, and 101b to 105b are mass flow controllers for adjusting the flow rate of gas from each cylinder, respectively.
c to 105c are gas pressure gauges, 101d to 105, respectively.
d and 101e to 105e are respectively /<A/pu, 101
f to 105f are pressure gauges each indicating the pressure within 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 basic holder 112 is provided such that a basic holder 18 is installed therein. The gas introduction pipes have a double concentric arrangement structure, with a first gas introduction pipe 109 into which gas from gas cylinders 101 and 102 is introduced, and a first gas introduction pipe into which gas from gas cylinders 103 to 105 is introduced. It has two gas introduction pipes 110. The tip of the gas introduction pipe 109 is narrowed to a diameter of about 1 mm to prevent the gas introduced from the gas introduction pipe 110 from back diffusing. Reference numeral 111 denotes a gas blowing pipe having a gas intervening space 106, the outlet of which is narrowed to a diameter of about 1 mm. Within the gas blowing tube, the gaseous raw material and the gaseous halogen oxidizer come into chemical contact to form a precursor. The precursor is blown onto the substrate from the outlet of the gas blowing tube to form a film.

Gas is supplied from the tube cylinder to each introduction pipe through gas supply pipelines 123 to 125, respectively. 10
Reference numeral 6 denotes a gas interposition space, and in the apparatus of this embodiment, it is a space of about 1 cm from the tip of the inner gas introduction pipe 109 to the gas blowing pipe 111.

Each gas introduction pipe, each gas supply pipeline and film forming space 1
20 is evacuated via the main vacuum pulp 119 by a vacuum evacuation device (not shown).

The base body 118 is installed at a desired distance from the position of each gas introduction pipe by moving the base body holder 112 up and down.

Reference numeral 113 denotes a substrate heater that heats the substrate 118 to an appropriate temperature during film formation, preheats the substrate 118 before film formation, and further heats the substrate 118 to anneal the film after film formation. .

The base heater 113 is connected to a power source 115 by a conductor 114.
The power will be supplied.

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

The process of forming an a-8i film using the apparatus of this embodiment will be described below.

Using the film forming apparatus shown in FIG. 1, a deposited film according to the method of the present invention was created as follows.
F2 gas diluted to 5% with He gas filled in the pump 103 was introduced into the gas blow-off tube 111 through the gas introduction tube 110 at a flow rate of 400 seconds through the gas introduction tube 109 at a flow rate of 20 seconds.

At this time, the pressure inside the gas blowing pipe was 5 torr. In addition, the pressure in the film forming space 120 is set to 1×1O−5To.
I made it rr. Quartz glass base (15cm x 15cm)
The distance between the gas blowing pipe 111 and the base is 30 cm.
It was set to A strong bluish-white light emission was observed in the intervention space 106. The substrate temperature (Ts) for each sample was set between room temperature and 400°C as shown in Table 1.

When gas was allowed to flow in this state for 30 minutes, a Si:H:F film having the thickness shown in Table 1 was deposited on the substrate.

Moreover, the unevenness in film thickness distribution was within ±5%.

It was confirmed by electron diffraction that all of the Si:H:F films formed were amorphous.

AJ comb-shaped electrodes (
A gap length of 200 μm) was deposited to prepare a sample for conductivity measurement. Each sample was placed in a vacuum cryostat, a voltage of 100μ was applied, and a microcurrent meter (YHP4140B) was used.
The current was measured and the dark conductivity (Od) was determined. 600 again
irradiated with light of 0.3 mw/7 nm, and the light guide rate (σ
p) was calculated. Furthermore, the optical bandgap (F g "t) was determined from the light absorption. These results are shown in Table 1.

Table 1 Comparative example Next, a -8i film was deposited using the apparatus shown in FIG.

This device has the same structure as the device shown in FIG. 1, with the gas intervening part 106 and gas blowing pipe 111 removed, and the same numbers as in FIG. 1 correspond to the same components as in FIG. 1. The gas introduction pipe 10 is arranged on a double concentric circle.
The inner gas introduction pipe 109 of the gas introduction pipes 9 and 110 is designed to be disposed at a position farther from the surface of the base body than the outer gas introduction pipe 110. This design takes gas mixing into consideration.

Hereinafter, the lower two digits of each number in FIG. 2 and each number in FIG. 1 correspond to the same number.

The substrate temperature was 200°C, the SiH4 gas flow rate was 20 sec,
F2 gas flow rate 400 sec diluted to 5% with He gas
Table 2 shows the film thickness, 0610918g0pt, of each sample prepared by varying the internal pressure. It should be noted that the film formation time was 3 hours each because it was not possible to obtain a sample with a film thickness that could be evaluated in 30 minutes.

Table 2 [Effects] From the above detailed description and each example, if the deposited film forming apparatus of the present invention is used, high-speed film formation can be achieved and at the same time, a deposited film with good quality can be obtained. Furthermore, it is possible to easily obtain a film with excellent productivity and mass production, and with high quality and excellent physical properties such as electrical, optical, and semiconductor properties.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of a film forming apparatus according to an embodiment of the present invention. FIG. 2 is a schematic diagram of a film forming apparatus used in a comparative example. 101-105... Gas cylinder, 101
a~105a...Gas introduction pipe, 101b~1
05b...Mass flow meter, 101C~10
5c... Gas pressure gauge, 101d to 105d and 101e to 105e... Valve, 101f to 1
05f・・・Pressure gauge, 106・・・・・・・・・
・・・・・・・・・・・・Gas intervention space, 10
9.110・・・・・・・・・Gas introduction pipe, 11
1・・・・・・・・・・・・・・・・・・・・・・・・
Gas blowoff pipe, 112......Base holder, 113...
・・・・・・・・・・・・Heater for heating the substrate, 11
6・・・・・・・・・・・・・・・Thermocouple for monitoring substrate temperature, 118・・・・・・・・・・・・・・・
・・・・・・・・・Base, 119・・・・・・・・・・
・・・・・・・・・・・・Represents a vacuum exhaust valve.

Claims (2)

[Claims] (1) A gaseous raw material for forming a deposited film and a gaseous halogen-based oxidant having the property of oxidizing the raw material are introduced into a reaction space and brought into chemical contact to bring them into an excited state. A deposited film forming method in which a plurality of precursors including precursors are generated, and at least one of these precursors is used as a source of a deposited film component to form a deposited film on a substrate located in a deposition space. 1. A deposited film forming apparatus comprising a mechanism for blowing out a gaseous raw material and a gaseous halogen-based oxidizing agent from a gas blowing port having an intervening space for both gases. (2) The deposited film forming apparatus according to claim 1, wherein the pressure within the air outlet is 10 torr or more, and the pressure within the film forming space is 1 torr or less.