JPH04290221A - Manufacture of thin film - Google Patents

Abstract

PURPOSE:To form a thin film having an excellent thin-film characteristic at a low temperature and at a high deposition speed by a method wherein a vaporized material and another gaseous material which has been introduced into a plasma on which a magnetic field has been exerted are introduced into the same chamber and the thin film containing both is formed on a substrate. CONSTITUTION:A chamber 1 and a chamber 2 are provided with vacuum lines; a crucible 5 into which a first material, e.g. Si, is put is installed at the inside of the chamber 2. The crucible 5 is heated by using an electron gun 6, and the material at the inside is vaporized. A substrate 3 is supported by a substrate holder 4 at the upper part of the crucible. On the other hand, a second material, e.g. H2, is introduced into the chamber 1 from a gas introduction port 11. The introduced second material comes into contact with microwaves and it is excited and generates a plasma. The plasma is confined in a magnetic field by a coil 8; it increases the concentration of radicals; it is supplied onto the substrate simultaneously with the first material which has been vaporized in the crucible; they are reacted; the thin film of a compound is deposited on the substrate.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a method for producing a thin film on a substrate, and more specifically to a thin film having good properties even on a substrate with relatively poor heat resistance such as an organic polymer film. The present invention relates to a method for forming .

0002

BACKGROUND OF THE INVENTION Thin films and thin film materials are used in many fields including the electronics field. Physical vapor deposition, chemical deposition, liquid phase growth, and the like are known as methods for producing compound thin films. The physical vapor deposition method includes
Vacuum deposition method, sputtering method, etc. are well known. In particular, methods for producing silicon and silicon-containing thin films, which are widely used as semiconductor thin films in solar cells, optical sensors, thin film transistors, electrophotographic photoreceptors, etc., include sputtering a silicon target in an active hydrogen atmosphere; Alternatively, a method of decomposing gas such as SiH4 by glow discharge is known.

0003

[Problems to be Solved by the Invention] The sputtering method, which is a conventional and well-known thin film formation method, has a high adhesion strength between the formed thin film and the base material, but the deposition (film formation) rate is low and it is difficult to mass-produce. It can be said that there is a lack of Although the vacuum deposition method has a relatively high deposition rate and is easy to apply to mass production, it has the disadvantage that the adhesion strength between the resulting thin film and the substrate is low. CVD is a well-known chemical deposition method, but its deposition rate is low, and in order to cause a sufficient chemical reaction, it is generally necessary to heat the base material to a high temperature. This means that it is not possible to use a base material with a relatively melting point such as. In the following, problems related to conventional silicon and silicon-containing thin film manufacturing methods will be explained in detail. It is difficult to obtain high-quality silicon and silicon-based alloy thin films obtained by sputtering because it is difficult to control the hydrogen content, which greatly affects film properties.

On the other hand, in glow discharge, dangling bonds,
Since a film with few defects such as voids can be obtained, this method has become the mainstream for forming silicon and silicon-based alloy thin films. However, the method of forming silicon and silicon-based alloy thin films by glow discharge has a problem in that the film formation rate is slow and productivity is poor. In order to increase the film formation rate, attempts have been made to increase the discharge voltage to increase the number of electrons that contribute to gas decomposition in the plasma, or to increase the reaction pressure to increase the concentration of source gas that contributes to decomposition. ing. By these means, it is possible to increase the film formation rate to some extent. However, the obtained silicon and silicon-based alloy thin films have poor photoconductive properties and many film defects, and are no longer satisfactory in terms of characteristics.

[0005] In addition, in conventional film forming methods, it is necessary to heat the substrate (base material) as in general thin film manufacturing methods, so materials with relatively low melting points such as polymeric materials cannot be used as substrates. Therefore, there is a problem that the range of application of the substrate material becomes narrower. In fact, amorphous silicon thin films on polymer substrates have already been developed in Japanese Patent Application Laid-open No. 149489/1983.
It is described in JP-A-55-4994 and JP-A-55-154726. However, in either case, the polymer substrate needs to have a certain degree of heat resistance since high-quality amorphous silicon is laminated thereon. Heat-resistant polymers generally include polyimide, polyamideimide, polyphenylene sulfide, polyetherimide, polyethersulfone,
Polyether ether ketone and the like are used, but when heated in the temperature range where amorphous silicon is deposited, solvents, water, etc. are released, and good quality amorphous silicon cannot be formed. Moreover, the price is high.

As mentioned above, conventionally,
There has been no known method for forming a thin film with good thin film properties and excellent adhesion to the base material at a high deposition rate on a base material with relatively poor heat resistance. In view of this situation, the present inventors have conducted intensive research and have arrived at the following invention, which makes it possible to form a thin film with excellent thin film properties at low temperature and high deposition rate.

[0007]

[Means for Solving the Problems] That is, the present invention provides a method for forming a thin film containing a plurality of types of materials on a base material by using a vaporized material (A) and a gas introduced into plasma to which a magnetic field is applied. This thin film manufacturing method is characterized in that a thin film containing (A) and (B) is formed on a substrate by introducing the other materials (B) in the same chamber into the same chamber.

(First Material) The first material (ie (A)) in the present invention is not particularly limited, but preferable ones include Li, Be, B, C, Na, Mg,
Al, Si, P, S, K, Ca, Sc, Ti, V, Cr
, Mn, Fe, Co, Ni, Cu, Zn, In, Ga,
Ge, As, Se, Y, Zr, Nb, Mo, Pd, Ag
, Cd, Sb, Te, Tb, Mo, Pd, Ag, Cd,
One or more of the group consisting of Sb, Te, Dy, Ho, Sn, Pb, Bi, their oxides, nitrides, halides, and intermetallic compounds can be used. Two or more of these can be used in combination as necessary.

[0009] Preferred first materials are Si,
C, Ge, SiO, SiO2, and a mixture of Si and SiO2. The first materials more preferably applied in the present invention are single crystal silicon and polycrystalline silicon. In the present invention, the heating method for vaporizing the first material is not particularly limited, but electron beam heating,
Induction heating, resistance heating, etc. can be preferably used.

(Second Material) The second material in the present invention, that is, (B), is not particularly limited, but H
2, N2, O2, etc., F2, Cl
2, Br2, etc., He, Ne, Ar, K
Rare gases such as r, Xe, saturated hydrocarbons, unsaturated hydrocarbons,
At least one of the group consisting of hydrogen silicide, phosphorus hydride, boron hydride, germanium hydride, metal halide, metal hydrogen halide, etc. can be used. Two or more of these can be used in combination as necessary.

[0011] In the present invention, preferably H2,
N2, O2, F2, Cl2, CH4, C2
H2, SiH4, B(CH3)3, NH3,
At least one of the group consisting of PH3, B2 H6, and rare gases can be used. In the present invention, especially when the purpose is to manufacture a non-oxide semiconductor thin film, H2, Six Hy, Cx Hy, Gex
Hy, Mx Xy, Mx X4x-yHy, X
2, N2 can be used. In addition, especially when the purpose is to produce an oxide compound thin film, O2, O3
, can be used. In the present invention, the method for obtaining plasma is not particularly limited, but
Microwaves, RF discharge, DC discharge, etc. can be preferably used.

(Dopant) In the present invention, a dopant may be added to the first material, the second material, or both, if necessary. (Magnetic field) The present invention is particularly characterized by applying a magnetic field to plasma. The magnetic flux density of the magnetic field at this time is
It is preferably in the range of about 100 Gauss or more, more preferably in the range of 300 to 2,000, and even more preferably in the range of 900 to 1,000.

[0013] In the present invention, a vaporized first material (A) and a gaseous material (B) introduced into a plasma are placed on a base material.
and (as a result, the radical generated from (B)),
(A) and (B) are reacted by simultaneously introducing them onto a substrate, and a thin film of the reacted compound is formed from (A) and (B). Compared to conventional CVD etc., the present invention has (B)
Since the radicals and ions generated from the material can be supplied to the substrate in large quantities independently of the material generated from the material (A), the material from the material (A) tends to undergo structural relaxation on the surface of the substrate. Therefore,
It is possible to form a high-quality thin film at a lower temperature than with CVD or the like. In the present invention, in particular, by applying a magnetic field to the plasma, electrons are spatially confined by the Lorentz force, and the electron concentration in the plasma is increased compared to when no magnetic field is applied. The electrons are introduced into the system from the gaseous material (B
) can generate high-density radicals or ions. In this case, it is not necessarily necessary to satisfy the electron cyclotron resonance conditions (input power frequency: 2.45 GHz, magnetic field strength: 875 Gauss). Furthermore, by applying a magnetic field, plasma can be generated at a lower pressure than when no magnetic field is applied, and radical ions generated from the material (B) can be controlled and supplied over a wider range.

[0014]

[Examples] In order to explain the present invention more specifically, Examples are shown below, but the present invention is not limited to these Examples. FIG. 1 is a diagram schematically showing an example of an apparatus according to the present invention. Chamber 1. , chamber 2. has a vacuum line (gas exhaust port) and can make the pressure inside the chamber lower than atmospheric pressure. Chamber 2. Inside is a "crucible" for putting the first material 5. This crucible is equipped with an EB gun 6. (electron gun) or resistance heating device, the material inside becomes vapor. When using two or more types of first materials, 5. This can be handled by providing two or more. At the top of the crucible, there is a base material 3.
．． is the board holder 4. Supported by Base material holder 4. is fixed at an arbitrary angle θ. Further, the substrate and the substrate holder are connected to the heater 12. However, when the substrate is a polymeric substrate such as a polymeric film, the heating must be controlled so as not to damage the substrate. On the other hand, the second material, i.e. (B), is in the chamber 1. Gas inlet 11. It is introduced from The second material introduced is a microwave power source 9. (usually around 2.45 GHz) is generated by the waveguide 10. When the material passes through the material and comes into contact with the second material, it is excited and generates plasma. This generated plasma is preferably applied to the coil 8. In this embodiment, the magnetic flux density of the magnetic field was made variable in the range of 100 to 3000 Gauss. The radicals generated in this plasma and the first material vaporized in the crucible are simultaneously supplied onto the base material or near the base material, react, and deposit a thin film of the compound on the base material. In order to obtain stable operation of the electron gun, a degree of vacuum of 1×10 −3 [Torr] or less was required.

Example 1 Polyethylene terephthalate was used as a base material, and hydrogenated amorphous silicon was deposited as a semiconductor film on the surface under the following conditions. Film forming conditions Vacuum degree: 3.2*10-5 Torr First material
: Polysilicon (N type) Second material : Hydrogen gas Microwave power : 200W Electron gun output : 6KV, 500mA magnetic flux density
: 1250 Gauss The dark conductivity of the obtained film is 1
*10-12 S cm-1, photoconductivity is 1*1
It was 0-7S·cm-1.

Example 2 A stainless steel substrate was used as a base material, and an SiO2 film was deposited as an insulating film on the surface thereof under the following conditions. Film forming conditions Vacuum degree: 1.5*10-5 Torr First material: Polysilicon (N type) Second material:
Oxygen gas microwave power: 1200W electron gun output
: 10KV, 100mA Magnetic flux density: 2
100 Gauss Substrate temperature: 200°C The conductivity of the obtained film is 1*10-12 S cm-1
Met.

Example 3 A glass substrate was used as a base material, and a germanium hydride film was deposited as a semiconductor film on the surface thereof under the following conditions. Film forming conditions Vacuum degree: 2.4*10-5 Torr First material: Germanium Second material: Hydrogen gas Microwave power: 200W Electron gun output: 6KV, 100mA Magnetic flux density
: 1200 Gauss Substrate temperature : 15
The photoconductivity of the obtained film at 0°C is 3.3*10-2S・cm-
It was 1. The dark conductivity of the obtained film was 1.2*10-2S cm-
It was 1.

Example 4 Using a glass substrate as a base material, an In2O3 film was deposited as a transparent conductive film on the surface thereof under the following conditions. Film forming conditions Vacuum degree: 2.8*10-4 Torr First material: Indium Second material: Oxygen gas Microwave power: 600W Electron gun output: 5KV, 100mA Magnetic flux density
: 100 Gauss Substrate temperature: 25° C. The conductivity of the obtained film was 5200 S·cm −1 .

Example 5 Using a glass substrate as a base material, an amorphous silicon carbide film was deposited as a semiconductor film on the surface thereof under the following conditions. Film forming conditions Vacuum degree: 4.2*10-5 Torr First material: Polysilicon (N type) Second material:
Methane gas microwave power: 1200W electron gun output
: 10KV, 520mA Magnetic flux density: 1
900 Gauss Substrate temperature: 95°C The photoconductivity of the obtained film is 2.8 * 10-5S cm-
It was 1. The dark conductivity of the obtained film was 3.6*10-10 S・c
It was m-1. The optical band gap of the obtained film was 2.2 eV.

[0020]

[Effects of the Invention] According to the present invention, a thin film of a compound can be produced on a base material using a base material at a relatively low temperature or room temperature, and the film formed has excellent physical properties. Can be manufactured.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram showing an example of the device in the present invention.

[Explanation of symbols]

1. chamber 1 2. chamber 2 3. Base material 4. base material holder 5. crucible 6. EB gun 7. gas exhaust port 8. coil 9. microwave power supply 10. waveguide 11. Gas inlet 12. heater

Claims (1)

[Claims] Claim 1: When forming a thin film containing multiple types of materials on a substrate, a vaporized material (A) and another gaseous material (B) introduced into a plasma to which a magnetic field is applied. was introduced into the same chamber, and (A) was placed on the substrate at 95°C or lower.
A thin film manufacturing method characterized by forming a thin film containing (B) and (B).