JPH02163363A - Production of transparent conductive film - Google Patents

Abstract

PURPOSE:To produce the transparent conductive film having a good electrical conductivity by incorporating gaseous H2O or gaseous mixture composed of O2 and H2O into a sputtering gas at the time of forming the transparent conductive film consisting of an In-Sn-O system on a substrate kept at a specific temp. CONSTITUTION:The transparent conductive film consisting of the In-Sn-O system is formed on the substrate kept at room temp. to a relatively low temp. of 200 deg.C by executing sputtering using an In2O3-SnO2 oxide or In-Sn alloy as a target and Ar or Ar+O2, etc., as a sputtering gas. The gaseous H2O or the gaseous mixture composed of the O2 and the H2O is incorporated into the sputtering gas in the above-mentioned film forming method. H atoms are taken into the film from the H2O and dangling bonds of atoms of In, Sn, O, etc., are compensated at the time of the above-mentioned film formation. The electrons to be trapped into the dangling bonds at the time of energization to the conductive film are, therefore, decreased. The electrical conductivity of the resulted transparent conductive film is improved in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing an In-8n-0-based transparent conductive film.

(Prior Art) Conventionally, an In-8n-0 based transparent conductive film (hereinafter referred to as an ITO film) has been created by a sputtering method, a vapor deposition method, a C1 method, or the like. Among these, in the sputtering method, there are cases where an In-8n alloy target is used and cases where an oxide target in which 5n02 is mixed into In2O3 are used, but in both cases, sputtering such as ^r is performed during sputtering. By mixing 02 gas into an inert gas and adjusting the amount of mixing, the 0 composition of the ITO film formed on the substrate is controlled to obtain good conductivity and transmittance.

(Problem to be solved by the invention) When manufacturing an ITO film by sputtering, if the substrate can be manufactured at a relatively low temperature of room temperature to 200°C, the ITO film can be formed on a substrate with low heat resistance, such as synthetic resin. It is desirable to be able to do so. However, at such low temperatures, the ITO film tends to become amorphous or a mixture of crystalline and amorphous, and when electricity is applied, conduction electrons are trapped in dangling bonds that occur in the film. There is a disadvantage that conductivity decreases.

The present invention is characterized in that the I
The purpose is to improve the conductivity of the TO film.

(Means for Solving the Problems) In the present invention, in a method for forming an In-5n-0 based transparent conductive film on a substrate at room temperature to 200°C by sputtering, H20 gas or The above problem was solved by mixing a mixed gas of 02 and H2O.

(Function) A substrate heated to room temperature to 200°C and, for example, an In-Sn alloy target are provided in a sputtering chamber, and a sputtering gas such as Ar gas is introduced to perform sputtering, and ITO is deposited on the substrate.
Forms a film. In this Suba Tsuta method, the IT formed
As mentioned above, the O film is amorphous or a mixture of crystalline and amorphous, and has poor conductivity.In order to improve this, in the present invention, H20 gas is added to the sputtering gas. Alternatively, sputtering was performed while mixing a mixed gas of H20 gas and 02 gas. When the H20 gas etc. is mixed into the sputtering gas, amorphous ITO is formed on the substrate.
H atoms are incorporated into the film, and dangling bonds of atoms such as In5SnsO are compensated for. Therefore, when electricity is applied to the ITO film, fewer electrons are trapped in dangling bonds, and the mobility and density of conduction electrons increase, resulting in improved conductivity. Note that when the substrate temperature becomes higher than 200° C., the ITO film is completely crystallized and no longer incorporates II atoms, so that the effect of introducing H20 gas etc. is lost.

(Example) An In2o3-5n02 oxide target mixed with 10Vt%5n02 was prepared in a sputtering chamber, and a DC
An ITO film sample was prepared by magnetron sputtering. The argon gas pressure during sputtering was 2×10-'Torr.
The thickness of the ITO film created was 1500 people, and the film forming rate was 900 people/...1n. The above conditions are the most typical method for producing an ITO film conventionally used.

Keeping the above conditions constant, the Ar gas has a certain partial pressure of 0.
2 gas, H20 gas, and a mixed gas of H20 gas and 02 gas were mixed to form a film on a substrate at room temperature (20° C.), and the resistivity of each film was determined as nj.

When mixing a mixed gas of H20 gas and 0□ gas,
The partial pressure of H20 gas is I x 10-'Torr and 2 x
Two pressures of 10"" Torr were used, and the partial pressure of the 02 gas was varied. The resistivity of the ITO film thus obtained is the first
It looked like the illustration. Since the types of gas are different, the gas pressure at which the resistivity becomes minimum differs, but the minimum resistivity value is smaller for H20 gas or a mixed gas of H20 gas and 0□ gas than for 02 gas. shows.

Next, in order to see how much H20 gas needed to be introduced, an ITO film was formed on the substrate while changing the H2020 gas, and the resistivity was measured. The results are shown in FIG.

The resistivity values shown in the figure indicate the minimum values (indicated by arrows in FIG. 1) when the 02 gas partial pressure is varied at each 820 gas partial pressure. As can be seen from this figure, the introduced H20 gas is effective in lowering the resistivity even in a small amount of 5 x 1O-6Torr, and 2 x to-'T
The resistance value becomes constant above orr.

FIG. 3 shows the effect of substrate temperature on resistivity. In this case as well, the minimum resistivity at each substrate temperature is determined and shown. As can be seen from the figure, the substrate temperature ranges from room temperature to 200°C.
℃, the resistivity is improved more when a mixed gas containing H20 gas is introduced than when a 0□ gas is introduced. However, at a temperature higher than 200° C., it is equivalent to introducing only 02 gas, and there is no effect.

Although a 1n2o3-5n02 oxide target was used as the tarp, the same effect can be obtained by using an In-Sn alloy target.

(Effects of the Invention) As described above, according to the present invention, in the method of forming an In-8n-0 based transparent conductive film on a substrate at room temperature to 200°C by sputtering, H20 gas is added to the sputtering gas. Alternatively, since the film was formed by mixing a mixed gas of 0□ gas and H20 gas, 11 atoms were incorporated into the film,
The danzoline 2' bond of atoms such as Ins Sns O is compensated, and an ITO film with good conductivity can be obtained.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the type of gas mixed in the sputtering gas and the relationship between gas partial pressure and resistivity. Figure 2 is a diagram showing the relationship between H2O gas partial pressure and resistivity. Figure 3 is a diagram showing the relationship between resistivity and the type of gas mixed in the sputtering gas. FIG. 2 is a diagram showing the relationship between temperature and resistivity. 3 other people

Claims (1)

[Claims] In-S is deposited on a substrate at room temperature to 200°C by sputtering.
A method for producing a transparent conductive film comprising the step of mixing H_2O gas or a mixed gas of O_2 and H_2O into sputtering gas.