JPH04290222A - Manufacture of thin film - Google Patents

Abstract

PURPOSE:To form a thin film having an excellent characteristic at a low temperature and at a high deposition speed by a method wherein a material which has been heated by using an electron beam and which has been vaporized and a gasified material which has been passed through a plasma are introduced into the same chamber and are deposited on a low-temperature 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 is heated by an electron-beam heating operation, and the material at the inside is vaporized. A substrate 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 and comes into contact with microwaves; it is excited and generates a plasma. Radicals generated in the plasma and the first material are fed simultaneously onto the substrate at 95 deg.C or lower, they are reacted and 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.

[0004] In the following, problems with conventional methods of manufacturing silicon and silicon-containing thin films 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. Also,
Conventional film formation methods require heating of 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. However, there is a problem that the applicable range of the substrate material is narrowed.

In fact, amorphous silicon thin films on polymer substrates have already been described in Japanese Patent Application Laid-open Nos. 149489-1989, 4994-1980, and 154726-1980. 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, polyether sulfone, polyether ether ketone, etc. are used, but when heated in the temperature range for depositing amorphous silicon, 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 the following features when forming a thin film made of multiple types of materials on a base material.
A first material (A) vaporized by electron beam heating;
A gaseous second material (B) introduced into the plasma,
(A) was introduced into the same chamber and placed on the substrate at 95°C or below.
This is a thin film manufacturing method characterized by forming a thin film with and (B).

(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. Preferred first materials are Si, C
, Ge, SiO, SiO2, and a mixture of Si and SiO2.

(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. In the present invention, preferably H2, N2, O
2, F2, Cl2, CH4, C2 H2, S
iH4, B(CH3)3, NH3, PH3,
At least one of the group consisting of 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, X2, N2 can be used. (M represents the metal shown in (A), and X represents a halogen.) Furthermore, when the purpose is to produce an oxide compound thin film, those containing O2 and O3 can be used.

(Plasma generation means) The method for obtaining plasma in the present invention is not particularly limited, but microwaves, RF discharge, DC discharge, etc. can be preferably used. Furthermore, a magnetic field can be applied to the plasma as necessary. (Dopant) In the present invention, the first
A dopant may be added to the first material, the second material, or both.

[0012] The present invention provides a vaporized first material (A) on a base material and a gaseous material (B) introduced into plasma.
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. The present invention is characterized in that electron beam heating is used as a means for heating the first material. In the present invention, particularly by using electron beam heating, there is an advantage that a thin film can be formed with less contamination of impurities generated from the heating source than by induction heating or resistance heating.

[0013]

[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 schematic diagram 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. 5. A "crucible" for putting the first material inside. The crucible is heated by electron beam heating, and the material inside becomes steam. 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 substrate holder-4. Supported by Base material holder-4. is any angle θ
is fixed. Furthermore, the base material and the base material holder are
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. "Introduced from." The second material introduced is a microwave power source 9. (Normally 2.45G
Microwaves 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 transferred to the coil 8 when necessary. After confining it with a magnetic field, chamber 2
．． may be introduced. 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.

Example 1 A polyethylene terephthalate film (film thickness: 100 μm) was used as a base material, and hydrogenated amorphous silicon was deposited as a semiconductor film on the surface thereof under the following conditions. (At this time, no magnetic field is applied.) Film forming conditions Vacuum degree: 3.9 x 10-
4 [Torr] First material:
Polysilicon (N type) second material:
Hydrogen gas microwave power: 200
[W] Crucible temperature: 2500
°C substrate temperature: 30
[℃] The dark conductivity of the obtained film is 1.3×
10-12 [S/cm], photoconductivity is 2.1×
It was 10-7 [S/cm].

Example 2 A glass 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. (At this time, no magnetic field is applied.) Film forming conditions Vacuum degree: 2.2 x 10-
4 [Torr] First material:
Polysilicon (N type) second material:
Oxygen gas microwave power: 1200
[W] Substrate temperature: 12
0 [℃] The conductivity of the obtained film is 1.7
×10-12 [S/cm].

Comparative Example 1 Polyethylene terephthalate was used as a base material, and hydrogenated amorphous silicon was deposited as a semiconductor film on the surface thereof under the following conditions. At this time, no plasma was generated for comparison. Film forming conditions Vacuum degree: 2.1×10-4 [Tor
r] First material: Polysilicon (N type) Second material: Hydrogen gas The dark conductivity of the obtained film is 3.2 × 10-11 [S/c
m], photoconductivity is 3.2×10-11 [S/cm]
Therefore, no photosensitivity was obtained.

Example 3 A glass substrate was used as a base material, and an In2O3 film was deposited as an insulating film on the surface thereof under the following conditions. (At this time, no magnetic field is applied.)
Film forming conditions Vacuum degree: 1×10-4
[Torr] First material: Indium Second material: Oxygen gas Microwave power: 1200 [W] Substrate temperature: 20
[℃] The conductivity of the obtained film was 8.5×102 [℃]
S/cm].

[0018]

[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 drawings]

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 5. crucible 6. EB gun 9. microwave power supply 10. waveguide

Claims (1)

[Claims] [Claim 1] When forming a thin film made of multiple types of materials on a substrate, a first material is vaporized by electron beam heating.
The material (A) and the gaseous second material (B) introduced into the plasma are introduced into the same chamber, and a thin film containing (A) and (B) is formed on a substrate at 95° C. or lower. A thin film manufacturing method characterized by forming.