JPH0542764B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method of forming a transparent conductive film on a substrate. [Prior art and problems to be solved by the invention] Conventionally, methods for producing this type of transparent conductive film include the so-called vapor deposition method and sputtering method, for example, as shown in FIGS. 2 and 3, respectively. The device is in use. In the figure, 11 and 11' are base materials made of an I _o -S _o alloy or its oxide, 12 and 12' are substrates on which a transparent conductive film is to be formed, and 13 and 1
3' is a heater for heating the substrate; 14;
14' is a mixed gas consisting of oxygen and an inert gas such as argon or helium, which is introduced into the reaction chambers 15, 15' to form an atmosphere in the reaction chambers 15, 15'; 16, 16' are reaction gases; Transfer the finished gas, etc. to reaction chamber 1.
5 and 15', an exhaust system 17 is a discharge power source, and in this device, the reaction chamber 1
In the vapor deposition method, the pressure within 5,15' is 10 ^-4 ~
10 ^-6 Torr, 10 ^-2 to 10 Torr for sputtering method,
Transparent conductive films are manufactured by heating both substrates 12 and 12' to 200 to 400°C.
In the case of the vapor deposition method, the so-called ion plating method may also be used, which utilizes the discharge generated between the base material 11 and the substrate 12 by applying a bias voltage between the two. The transparent conductive film thus obtained is transparent and conductive, and specifically has been measured to have a visible light transmittance of 90% or more and a specific resistance of 1×10 ^-3 Ωcm or less. However, in such a conventional manufacturing method, the substrates 12, 12' must be heated to about 200 to 400°C, and therefore cannot be applied to substrates with low heat resistance. During the film reaction, external impurities enter and reduce the purity of the transparent conductive film, and furthermore, after the film formation reaction is completed, the temperature of the formed transparent conductive film drops extremely from the heating temperature to room temperature. There were disadvantages such as residual internal stress within the film due to thermal strain. In view of the above circumstances, an object of the present invention is to provide a manufacturing method that can be carried out at a temperature around room temperature, can be applied to substrates made of various materials, and can form a transparent conductive film with significantly improved quality. shall be. [Means and effects for solving the problems] In the method of the present invention, the steam generated by heating the base material and the activated gas containing oxygen are heated to substantially room temperature through an oxidation reaction. A transparent conductive film is formed by depositing the transparent conductive film on the substrate held at a certain level. Therefore, since the conventional heat resistance is no longer necessary for the substrate, the method of the present invention can be applied to a wide range of substrates made of various materials, and the substrate has extremely high quality without internal stress. A transparent conductive film can be formed. [Example] Fig. 1 shows a schematic configuration of an apparatus suitably used in the method of the present invention, in which 1 is a base material made of indium, tin, an alloy thereof, or an oxide thereof; is a substrate maintained at approximately the same temperature as room temperature, and this substrate is grounded. Reference numeral 3 refers to an electron beam heating device that applies predetermined electric and magnetic fields to an electron beam 3' consisting of thermionic electrons to appropriately accelerate or deflect the electron beam 3' and cause it to collide with the base material 1; 4, a reaction chamber 5; The volume ratio c of oxygen introduced into the interior and an inert gas such as argon or helium is 0≦c<100 (c=volume of inert gas/
6 is a hot cathode type activation device capable of ionizing or otherwise activating the reaction gas 4 with accelerated thermionic electrons and releasing it into the reaction chamber 4; 7; is an accelerating power source capable of bringing the potential of the substrate 2 to a negative potential of at least several hundred volts with respect to the hot cathode type activation device 6, and accelerating the activated reaction gas 4 toward the substrate 2;
8 is an exhaust system. Next, the method of forming a film on the substrate 2 using the above apparatus will be explained. The pressure inside the reaction chamber 5 is maintained sufficiently low by being exhausted by the exhaust system 8, and the base material 1 is first heated with an electron beam. When heated by the device 3, the base material 1 reaches its melting point, and is further heated to the reaction chamber 5.
(arrow 1'). During this heating, the base material 1 is heated locally by the electron beam 3', so this heat does not affect the substrate 2, and the temperature of the substrate 2 is maintained at approximately room temperature. ing. On the other hand, the reaction gas 4 is ionized and activated when passing through the hot cathode type activation device 6, and the ions are further generated by the electric field between the activation device 6 and the substrate 2 by the acceleration power source 7. As it is accelerated, it becomes a gas flow 4' and the substrate 2
It is forced to flow towards. Furthermore, this gas flow 4'
The current density in the substrate 2 caused by is
It reaches 10mA/ ^m2 to 10A/ ^m2 , and the acceleration power supply 7
If the electric field is zero, the reaction gas 4 is not accelerated thereby, but in this case too it can diffuse into the reaction chamber 5 and reach the substrate 2. The pressure inside the reaction chamber 5 at this time is 10 ^-5 to ^{10 -3} Torr.
In this way, the vapor produced by evaporating the base material 1 and the molecules constituting the reaction gas 4 collide with each other on or near the substrate 2 and react with each other, and as a result, an oxide film is formed on the substrate 2. Forced to form. The film forming rate can be adjusted appropriately within the range of 0.5 Å/sec to 500 Å/sec, and the formed transparent conductive film has a visible light transmittance of 90% or more and a specific resistance of 10 ⁻³ Ωcm or less. More specifically, the film forming conditions a shown in Table 1,
Under b, film formation results A and B shown in Table 2 were obtained, and in both cases, the transparent conductive film formed as shown in Table 2 had a visible light transmittance of 90% or more and a specific resistance.
10 ^-3 Ωcm or less.

【table】

〔Effect of the invention〕

As described above, the method of the present invention is not limited by the material of the substrate, so the range of application can be expanded, and the method has advantages such as improving the quality of the formed transparent conductive film and preventing deformation of the substrate due to film formation. have

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of an apparatus used in the manufacturing method according to the present invention, and FIGS. 2 and 3 are diagrams showing the respective configurations of the apparatus applied to the conventional manufacturing method. DESCRIPTION OF SYMBOLS 1... Base material, 2... Substrate, 3... Electron beam heating device, 4... Reaction gas, 5... Reaction chamber, 6... Hot cathode type activation device, 7... Acceleration power source.

Claims (1)

[Claims] 1. A method for producing a transparent conductive film in which a base material is heated and evaporated in a reaction chamber to form a transparent conductive film on a substrate, wherein the base material is heated at a temperature of 10 ^-5 to 10 ^-3 Torr. Under the atmosphere,
The base material is heated and evaporated using an electron beam heating device, and a reactive gas consisting of a mixture of oxygen and an inert gas is applied to the substrate at a current density of 10 mA/
The vapor of the base material and the reaction gas are heated to substantially room temperature by activating the base material with a hot cathode activation device and accelerating the flow toward the substrate using an accelerating power source so that the current is ¹⁰ A/m ² to 10 A/m 2 . A method for producing a transparent conductive film, characterized in that the reaction is carried out on or near the substrate held by the substrate. 2. The base material is made of indium, tin, an alloy thereof, or an oxide thereof,
A manufacturing method according to claim 1.