JPS5843899B2 - Method for forming transparent conductive film - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for forming a transparent conductive film.

In recent years, with the progress of semiconductor engineering, thin film devices having at least one semiconductor layer have been developed and are being industrialized, and their versatility is extremely large.

For example, thin film devices are used in display devices such as liquid crystal and plasma, which have made remarkable progress in recent years.

Examples of methods for forming thin films in thin film devices include vacuum evaporation, sputtering, and ion blating, which is becoming increasingly important at the current research stage.

The technique of forming a transparent conductive film is known as a typical example of this thin film application, but there is a problem in the manufacturing method that a thin film having a desired resistance value cannot be obtained with good reproducibility.

For example, a thin film with low resistance can be obtained with good reproducibility on a glass substrate heated to 73D by using a well-known electron beam evaporation method (one of the vacuum evaporation methods) from a pellet with a certain mixture ratio of In203Sn02 for the following reasons. It was extremely difficult.

That is, the base material in the pellet, I n 20
3 and the doping material for the valence side leg S n
It is difficult to disperse uniformly when mixed with 02.

Various causes such as thermal dissociation and differences in vapor pressure are cited as reasons for inhibiting reproducibility.

This also applies to other methods, such as sputtering and binary evaporation.

In other words, all known means have poor reproducibility.

In view of these circumstances, the present invention forms a transparent conductive film layer with a high resistance of IOKΩ/Sg or less, and passes through this transparent conductive film layer.
By implanting ions into this transparent conductive film layer in a heated state, it is possible to suppress the amount of defects that occur during ion implantation, that is, the generation of lattice defects, and promote lower resistance, resulting in good reproducibility and control of the resistance value. The present invention aims to provide a method for forming a transparent conductive film with good properties.

Below, one embodiment of the present invention will be described with reference to the drawings.
First, a transparent conductive film layer, for example, an In203 layer 2, is formed on a glass substrate 1 shown in FIG.

This In 20 s layer 2 is formed by known means, such as sputtering or electron beam evaporation.

The In2O3 layer 2 has a film thickness of 200OA and a relatively high resistance of IKΩ/0 and a surface resistance of 0.
S9 to IOKΩ/Sg is controlled to, for example, IKΩ/Sg.

The controllability of the resistance value on the order of X is extremely good because the surface resistance is relatively high.

Next, Au, Ta, and AI are deposited on both ends of the main surface of the In2O3 layer 2.
A metal electrode layer 3 such as the above is formed by known means, and the electrode layer 3 is connected to a 77 [l thermal aeration source 4.

Then, when the interlayer distance of the electrode layer 3 is A 1 cmJ and the width of the glass substrate 1 is 5 AJml, an alternating current or direct current zoov voltage is applied to both ends of the In2O3 layer 2.
n 203 Layer 2 is directly heated with electricity.

The In2O3 layer 2 reaches temperature equilibrium depending on the holding structure of the glass substrate 1 for ion irradiation, the thickness of the substrate 1, etc.
This will vary slightly, but considering the design of thermal insulation, 5~
Temperature equilibrium is reached in IO minutes.

In this example, the temperature reached 200°C after 5 minutes.

The In2O3 layer 2 is irradiated with the ion beam 5 while the In2O3 layer 2 is held at the above-mentioned high temperature, that is, in an annealed state.

Sn ions are used as this ion beam 5, and 1
It is carried out in a vacuum of 0-5 to IO-6 m7MHg.

This Sn ion irradiation may be performed by vaporizing the metal to form a plasma and extracting SnM ion from this plasma, or by using a 5nC14 high frequency plasma ion source.

Furthermore, the zero velocity analysis system, deceleration system, scanning system, etc. for ion implantation are based on known means.

In this way, 10 Sn+ ions were added to the In2O3 layer 2.
15~10161on/cn! Based on I n 203 and 10~]OOΩ/Sg by L injection
It was possible to form a transparent conductive film with good reproducibility and a surface resistance value as low as .

Here, it is sufficient for the energy of Sn+ ions to be about 5 KeV, but this energy is
It is determined by the thickness of layer 2 and the required distribution within the injection layer.

Note that when heating is performed using a constant voltage power supply, the resistance value decreases and the amount of heat generated per unit changes as the ions are implanted.
Slope control is performed to provide constant temperature control to the injection layer.

In order to control the slope, a method is used to obtain a control signal by feeding back the temperature of the injection layer, but this method is not always necessary.

Alternatively, it may be formed by applying a constant voltage without performing constant temperature control as described above, and under a state where the temperature of the In2O3 layer 2 increases as the resistance value of the In2O3 layer 2 decreases due to ion implantation. Also, a transparent conductive film with good reproducibility can be obtained.

In the above examples, it was possible to obtain a transparent conductive film having extremely good controllability of the desired resistance value.

This is due to the controllability of ion implantation.

That is, the implanted ions are charged particles and can be measured with high precision due to their electrical quantity.

Moreover, since the injection layer is kept at a high temperature during injection, it is possible to omit heat treatment as a post-process.

FIG. 2 shows another embodiment.

In other words, IOOA of Au is deposited on a glass substrate 6 with a thickness of two plates.
An electrode layer 7 is formed, and a Z of 400OA is formed on the electrode layer 7.
After forming the n3 layer 8, an In2O3 layer 9, which is a transparent conductive film layer, is formed on the Zn3 layer 8, and metal electrode layers 10 of Au, Ta, A, I, etc. are formed on both ends of the main surface of the In2O3 layer 9. , and further the electrode layer 10 is connected to a 7JD thermal power source 11.
Connect to.

Then, while the In2O3 layer 9 is heated to a high temperature as described above, the Mn ions 12 are heated to an energy of 10 to 20K.
ev, by implanting at an injection amount of 1014 to 1016 ion/i, it is possible to create a luminescent center of ZnS and at the same time improve the transparency and electrical conductivity of In2O3, which has extremely excellent practical effects. It is.

In addition to the above-mentioned embodiments, thin films suitable for various uses can be formed by combining material layers and substrates, pattern implantation, etc., and are extremely versatile.

Further, a combination of increasing the resistance value of the semiconductor layer by ion implantation is also possible.

Furthermore, the substrate may include semiconductors such as Si and Ge, and Ga.
It can be applied to any of intermetallic compound semiconductors such as AS and GaP@;, polymer molded products, films, etc., and similar effects can be obtained.

As detailed above, the present invention can provide a method for forming a transparent conductive film with good reproducibility and good controllability of resistance value, that is, good controllability of the concentration of dopant impurities in the transparent conductive film layer. In addition, it was possible to provide a method for forming a transparent conductive film that does not require sophisticated technology to maintain good controllability and can be easily used in a factory.

[Brief explanation of drawings]

FIGS. 1 and 2 are cross-sectional views of a thin film device for explaining the present invention in detail. 1.6 is a substrate, 2 and 9 are semiconductors, and 5.12 is an ion.

Claims (1)

[Claims] 1 A transparent conductive film layer with a high resistance of 078 g or less is formed on 10, and ions are implanted into the transparent conductive film layer while the transparent conductive film layer is heated for 1 time to reduce the resistance of the transparent conductive film layer. A method for forming a transparent conductive film that promotes