JPS59145039A - Formation of membrane - Google Patents

Abstract

PURPOSE:To form a membrane with uniform film characteristics over a large areal region, by introducing activated hydrogen gas into a tank in which a substrate and an evaporation source are provided while vapor depositing a substance evaporated from the evaporation source in such a state that electron beam is made to irradiate in the vicinity of the substrate. CONSTITUTION:Hydrogen gas activated or ionized by a high frequency discharge type gas discharge tube 4 is introduced into a tank 1 in which a substrate 2 and an evaporation source 3 are provided and the evaporated substance from the evaporation source 3 is vapor deposited on the substrate 2 while electron beam is made to irradiate in the vicinity of the substrate by an electron beam generator 8 to form a membrane. By this method, a hydrogen atom can be introduced in high efficiency and the membrane having uniform characteristics can be formed over a large areal region.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of forming thin films by vapor deposition.

Recently, amorphous silicon (hereinafter referred to as "a-8iJ") has been viewed as very useful as a material for forming batteries, electrophotographic photoreceptors, etc.

This a-8i can be formed as a thin film by various methods, but for this a7Si, it is necessary to add hydrogen atoms to seal the dangling bonds, and only then can a large darkness be formed. Hydrogen-containing a-8L (hereinafter referred to as "a,-8t:HJ") having resistance and photoconductivity is obtained, which can be put to practical use.

Conventionally, as a method for forming a thin film of a-8t:H, for example, hydrogen gas is glow-discharged in a high-frequency discharge type gas discharge tube, and in the presence of activated hydrogen or ionized hydrogen generated thereby, silicon is A method of #wearing has been proposed.

However, the main problem with this method is that the ionized hydrogen produced in the high-frequency discharge type gas discharge tube has a short lifespan, so if the distance between the gas discharge tube and the vapor deposition substrate is large, water-based atoms cannot be sufficiently introduced.

Therefore, a high film formation rate cannot be obtained, and a thin film of a-8i:H having the characteristics of F9r cannot be formed.

When a high-frequency discharge temperature gas discharge tube is brought close to the base body,
The temperature of the substrate rises due to electromagnetic induction, which adversely affects the formed thin film, such that A-8i, for example, crystallizes and its properties are greatly impaired. In addition, installing a high-frequency discharge type gas discharge tube at a certain distance from the base and inputting a large amount of power to it may cause the matching between the discharge space and the power source to collapse.
This is never a good idea as it will reduce efficiency and cause destruction of the gas discharge tube.

In addition to the methods described above, recently, hydrogen gas is introduced directly into a tank containing a substrate and a silicon evaporation source, and the hydrogen is activated or ionized by irradiating it with an electron beam. A method was developed in which silicon was vapor-deposited onto a substrate. According to this method, a-8i is formed:
It is possible to uniformly introduce hydrogen atoms into H, and there is an advantage that a-8i:H with almost no contamination can be produced.

However, even in this method used for electron &l', activation or ionization of hydrogen gas occurs only in the very vicinity of the electron beam generator, so a thin film with uniform characteristics cannot be formed over a wide area. There is a drawback that the efficiency of using the 11-strand wire is low.

The present invention was made based on the above circumstances, and its purpose is to form a thin film over a large area that can introduce hydrogen atoms with high efficiency and has uniform characteristics. We are here to provide you with a possible method.

The present invention is characterized in that activated or ionized hydrogen gas is introduced into a tank provided with a substrate and an evaporation source using a high-frequency discharge type gas discharge tube, and the vicinity of the substrate is irradiated with an electron beam. However, the evaporation material is evaporated from the evaporation source to form a thin film.

The present invention will be explained in detail below with reference to the drawings.

In one embodiment of the present invention, as shown in FIG. 1, a evaporation substrate 2 and a source 8 containing silicon as an evaporation material are provided facing each other in a pelger l forming a evaporation chamber. , hydrogen gas is supplied into the Pelger l through a high-frequency discharge type gas discharge tube 4 connected so that its outlet faces the substrate 2, and a vacuum pump (not shown) is supplied through an exhaust path 5. After evacuating the inside of the perfusion jar 1, the inside of the perfusion jar 1 is placed under pressure of, for example, 10-4 Torra degrees. The substrate 2 is heated to a temperature in the range of 850 to 450C by a heater 6, and is heated to a temperature of O to -10K by a DC power supply 7.
While applying a negative bias voltage of V, the electron beam generator 8 disposed directly facing the substrate 2 emits a stain beam to uniformly scan the substrate 2.

The evaporation source 8 is heated by a co-heater 9 (for example, 1$) to evaporate silicon, which is an evaporation substance, and thereby the substrate 2
A thin film of a-8t:H is formed on the surface of .

An example of the high frequency discharge type gas discharge tube 4 will be explained.

As shown in FIG. 2, a discharge space 91201 made of cylindrical glass, for example, surrounding the discharge space 200, a probe electrode 202 and a shielding plate 208 provided at one end of this discharge space member 201, and this discharge space member 201 Accelerating and focusing electrode 205 with outlet 204 provided at the other end, quartz sleeve 20
6 and canaluminum pole 207, and height 88 in the discharge space 200.
Annular electrodes 208 and 209 for applying an electric field and a magnetic field coil 210 for interlocking the rotation of electrons are formed, and a high frequency voltage is applied between the annular electrodes 208 and 209 to generate a plasma on the discharge wall M2O0. , probe electrode 202
Activated hydrogen atoms or molecules and ionized hydrogen ions or molecular ions or composite molecular ions are ejected from the outlet 204 by applying appropriate voltages to the acceleration and focusing electrode 205 and the acceleration and focusing electrode 205, respectively. The probe voltage in this discharge tube is 100 to 5, depending on the required active species.
Approximately kV is applied, and the acceleration and focusing voltage is 100 to 20k.
It is said to be about V.

Since the present invention is a method as described above, activated or ionized hydrogen generated in the high frequency discharge type gas discharge tube 4 is introduced toward the substrate 2, and Since the space directly below is irradiated with an electron beam from the electron beam generator 8, activated hydrogen or iminated hydrogen exists at a high density in the space, and this space is also a space where the vapor of the evaporated substance flies. Therefore, a deposited film into which hydrogen atoms are introduced with extremely high efficiency is formed on the substrate z.

In the present invention, since hydrogen gas is introduced through the high-frequency discharge type gas discharge tube 4, in the space directly below the substrate 2, hydrogen gas that has been activated or ionized but whose life has expired is removed. There are many species, but these species are in an excited state where they become activated or ionized very easily when a small amount of energy r is applied.

This is irradiated with an electron beam from the electron beam generator 8, so
In addition to the activation and ionization of hydrogen that has not been activated or ionized by the gas discharge tube 4, the above-mentioned hydrogen in the excited state is extremely easily activated or ionized. As a result, in the space directly below the substrate 2, the density of hydrogen in a high energy state that can be introduced into the deposited film is significantly high.As a result, the a- 8
i:H and other thin films can be formed. As will be understood from the explanation of the specific example described below, by using both the high-frequency discharge type gas discharge tube 4 and the electron beam generator 8, a thin film with excellent characteristics can be spread over a much wider area of the substrate 2. This is extremely advantageous since it can be formed over a large area.

However, the operation of the electron beam generator 8 improves the consistency of the high-frequency discharge type gas discharge tube 4, so that the gas discharge can be carried out efficiently, and as a result, a high-quality thin film can be formed for a long time. It can be performed stably over a long period of time.

Note that a nitride thin film can be formed by introducing a nitrogen-containing gas such as ammonia gas or nitrogen gas into the Pelger 1.

When carrying out the method of the present invention, the substrate for vapor deposition is not limited to a substrate, but a drum-shaped or moving film can also be used.

Various types of electron beam generators can be used as the electron beam generator 8, and it is not limited to the so-called point type, but also a 1M type that extends two-dimensionally as shown in FIG. 8, or a 1M type that extends two-dimensionally as shown in FIG. You can also use a room that expands in eight dimensions. In these figures, F is a filament, S is a filament power source, E is an extraction electrode, D is a DC power source of the extraction electrode E, %W is an electron beam transmission window formed in the extraction pole E, and e is an electron beam.

The method of the present invention can form a thin film of a substance that would otherwise cause dangling bonds by mere vapor deposition, with the dangling bonds sealed.
Therefore, by changing the evaporation substance of the evaporation source 8, a-8
The thin film 1 other than t:H can be formed, for example, amorphous silicon carbide, amorphous silicon nitride, amorphous tantalum nitride, amorphous titanium nitride, or other thin films.

To heat the silicon of the evaporation source 8, it is possible to use resistance heating means in addition to electron beam heating means as in the illustrated example.

Next, specific examples of the present invention will be described.

Silicon was deposited using a vapor deposition apparatus having the configuration shown in FIG. 1 under the following conditions. However, an aluminum drum having a diameter of 12 Crn and a length of 80 Crn was used as the base, and was rotated at a rotational speed of 20 r, p, m, and the electron beam generator 8 was provided on one end side of the base.

[Vapor deposition conditions]

Vacuum level inside Pelger: 0-4 Torr substrate temperature '850tl:'substrate voltage'
-6kV Evaporation source electron beam heater voltage: -6kV Emission current: 800 mA Gas discharge tube driving power: 100W Electron beam generator running voltage: -ekV Emission current:
400 mA same scanning cycle ・
10 Hz hydrogen gas supply amount '200
SCCM deposition rate: 25 A/s Deposition time: 2,000 seconds or more The drum having a-8i:H thin film formed as described above has dark conductivity σ1 and 5X101 of the thin film.
Photoconductivity σ due to light irradiation of 5 photons/i° seconds.

We found that over the entire length of the drum, 9 σD = lO ~ 10''''8 (Ω-cm ) −'σG =
10 (Ω-cm) −', and was found to have uniformly extremely high photoresponsivity.

On the other hand, when similar measurements were performed on a drum on which a thin film of a-8i:H was formed in the same manner except that the drive of the electron beam generator 8 was stopped, +7= 10-9～10″″6 (Ωaan)-'a
= 10-5 to 1 O-6 (0 g cm)-1, the photoresponsiveness was not that high, and the non-uniformity was severe.

In addition, similar measurements were performed on a drum on which a thin film of a-8i:H was formed in the same manner as described above, except that the drive of the high frequency 11L type gas discharge tube 4 was stopped, and it was found that the electron beam generator 8 was In the half-length region of the one end where In the half area of the reed and the other end 11], σ,
= 10-8 ~ 1O-7 (Ω-cm)-1σG-1
0 to 10''-7 (0 m on ) -16 The non-uniformity of the photoresponsivity in the length direction was large, and even though the photoresponsivity was present, it was not high.

As described above, according to the present invention, water atoms can be introduced with high efficiency, and a thin film having uniform characteristics can be formed over a large area.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an apparatus that can be used to implement the thin film forming method of the present invention, FIG. 2 is an explanatory diagram showing an example of a DC discharge type gas discharge tube, and FIGS. 8 and 4 are an electronic IW generator. FIG. 2 is an explanatory diagram of main parts in the example of FIG. l...Pelger 2...Substrate 8...Evaporation source 4...Gas discharge tube 5...Exhaust path
6... Heater 8... Electron beam generator
9...Electron beam heater F...Filament 1.
k...Extraction electrode W...Electron beam transmission window 200
...Discharge space 201...Discharge space member 205.
...Acceleration Focus I! Pole 207...Canalumi pole 20
8,209...Annular electrode 210...Magnetic field coil 1st biliary science 2R

Claims (1)

[Claims] 1) Activated or energized hydrogen gas is introduced into a tank provided with a substrate and an evaporation source through a high-frequency discharge gas discharge tube, and an electron beam is emitted near the substrate. A method for forming a thin film, characterized in that the evaporated substance from the evaporation source is deposited while irradiating, thereby forming a thin film. Z) 'The method for forming a thin film according to claim 1, wherein the irradiation with the It son beam is performed while scanning.