JPH11323531A - Transparent electrically conductive film excellent in workability - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a transparent electrode low having electric resistivity and high visible ray transmissivity, easy to be etched and excellent in workability by allowing it to have a compsn. essentially consisting of the oxide of In, furthermore contg. a specified amt. of Ge and contg. a specified amt. of Sn according to necessary and composing its structure of amorphous one. SOLUTION: In a transparent electrically conductive film essentially consisting of the oxide of In, by atom, 2 to 12% Ge is incorporated to form the structure of the film into the amorphous one, and, if required, <=5% Sn is moreover incorporated to improve its workability. The amorphous structure of the film can be obtd., at the time of sputtering an In2 O3 target contg. a prescribed amt. of Ge in an inert gas atmosphere contg. gaseous oxygen and forming a film on a substrate, by controlling film forming conditions such as the film forming temp. the oxygen partial pressure, the film forming rate or the like. In this way, the transparent electrically conductive film having >=80% visible ray transmissivity and <=0.01 Ω . cm electric resistivity is formed and is made capable of corresponding to high precision suitable for a transparent displaying electrode such as a transistor type liq. crystal display.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent conductive film excellent in processability, and more particularly to a technical field relating to a transparent conductive film excellent in processability suitable as a transparent electrode for a display electrode of a thin film transistor type liquid crystal display. Belong.

[0002]

2. Description of the Related Art A transparent conductive film having a low electric resistance and a high visible light transmittance is used in many fields such as a transparent electrode of a flat display, a transparent electrode of a solar cell, and a touch panel.

[0003] Among them, a liquid crystal display; Liquid Cryst
The al Display (hereinafter referred to as LCD) is widely used in personal computers and display devices as a lightweight, thin and high-resolution display device, and a transparent conductive film is indispensable as a transparent electrode for LCD.

[0004] Such LCD screen display is performed by controlling the arrangement of liquid crystal molecules by an applied voltage and adjusting the amount of light transmitted from the backlight to the screen.
Therefore, in order to drive the liquid crystal, a transparent conductive film having low electric resistance and high transmittance in a visible light region is used. At present, a transparent conductive film used as a transparent electrode of an LCD is In ₂ O ₃ (; Indium Tin Oxide) to which Sn is added (hereinafter referred to as ITO).

[0005] By the way, it is necessary to form a pixel for liquid crystal display, and it is necessary to form a pattern of a transparent electrode according to the pixel by etching. For example, in a simple matrix type LCD, a transparent electrode also serves as a wiring and a pixel electrode, and it is necessary to form a pattern according to a pixel width. In an active matrix type LCD, an independent pixel electrode is required for each pixel, Fine patterning corresponding to the size of the pixel is required. Here, a transparent conductive film as a pixel electrode has a processing accuracy of 10 μm or less,
It is required to be able to process about μm. As a method of processing the transparent conductive film, a method of wet etching with an etching solution such as nitric acid, hydrochloric acid, a mixed acid of hydrochloric acid and nitric acid, hydrofluoric acid, an aqueous solution of ferric chloride, or a mixture of these with an oxidizing agent is used. Mainstream.

[0006] However, it is not easy to etch ITO formed by a usual magnetron sputtering method. That is, ITO is usually formed by a magnetron sputtering method, but in order to reduce the resistance of the formed ITO, the substrate is heated to about 200 ° C. during the film formation, and at this time, the ITO is crystallized. Become This crystallized ITO film is hard to be etched and is not easily etched.

Therefore, in order to increase the efficiency of forming an etching pattern, it is important to develop a transparent conductive film that is easily etched, that is, a transparent conductive film that is excellent in workability.

As such a transparent conductive film which can be easily etched, an amorphous film of ITO (here, an amorphous film means a film having a maximum width at half maximum of 5 degrees or more in an X-ray diffraction pattern). ). Therefore, attempts have been made to form a transparent electrode from an amorphous ITO film that can be more easily etched, and a method of forming such an amorphous ITO film is being studied. For example, JP-A-4-48516 discloses that
A method of forming an amorphous ITO film by forming ITO at a low temperature is disclosed. Japanese Patent Application Laid-Open No. 3-64450 discloses that a film such as hydrogen is introduced into a sputtering gas to form a film. A method is disclosed.

[0009] However, ITO formed at a low temperature as described above has drawbacks such as an increase in electrical resistivity and an increase, and a decrease in visible light transmittance and a decrease. Further, the method of forming a film by introducing a gas such as hydrogen into the sputtering gas has a problem that a sufficient sputtering rate cannot be obtained.

In the future, development of a transparent conductive film that is easy to etch is indispensable for LCDs with higher definition, and therefore has low electric resistivity and high visible light transmittance, is easy to etch, and has excellent workability. Development of a transparent conductive film has been desired.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and has as its object to have a low electric resistivity and a high visible light transmittance and to be easily etched and processed. It is an object of the present invention to provide an amorphous transparent conductive film which is excellent in performance and can cope with high definition of LCD.

[0012]

In order to achieve the above-mentioned object, a transparent conductive film according to the present invention is a transparent conductive film according to claims 1 to 6, which has the following structure. is there. That is, the transparent conductive film according to claim 1 is a transparent conductive film containing an oxide of In as a main component, and has a workability characterized by containing Ge and having an amorphous structure. It is an excellent transparent conductive film (first invention).

The transparent conductive film according to claim 2 is the transparent conductive film excellent in processability according to claim 1 containing Sn (second invention). The transparent conductive film according to claim 3 has a Sn content of
3. The composition according to claim 2, wherein the content is 5 atomic% or less with respect to the total of Sn content and In content.
A transparent conductive film having excellent processability as described (third invention).
In the transparent conductive film according to the fourth aspect, the content of Ge is 2 to 12 atomic% with respect to the total of the Ge amount and the In amount.
A transparent conductive film having excellent processability as described (fourth invention).
The transparent conductive film according to claim 5 has a visible light transmittance of 80% or more and an electric resistivity of 0.01 Ω · cm or less.
It is a transparent conductive film excellent in processability described in 3 or 4 (fifth embodiment).
invention). The transparent conductive film according to claim 6 is the transparent conductive film according to claim 1, 2, 3, 4, or 5 used as a transparent electrode of a liquid crystal display (sixth invention).

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The transparent conductive film according to the present invention can be formed, for example, by a sputtering method as follows. That is, a substrate is placed in a sputtering apparatus, while a sputtering target such as In ₂
A composite target having a Ge chip placed thereon is placed on an O ₃ target, and the substrate is heated in an inert gas atmosphere containing oxygen gas, and then an electric field is applied between the substrate and the composite target. By applying
Formation (film formation) of a transparent conductive film made of In ₂ O ₃ containing Ge
can do. At this time, the structure of the transparent conductive film to be formed depends on the film formation conditions such as the Ge content in the film, the film formation temperature (heating temperature of the substrate), the oxygen partial pressure in an inert gas atmosphere, and the film formation rate. It becomes crystalline. Then, a transparent conductive film mainly containing an oxide of In and containing Ge and having an amorphous film structure, that is, a transparent conductive film according to the present invention can be obtained. . In addition, in the above-mentioned composite target
The Ge content can be changed by changing the surface area ratio between the In ₂ O ₃ target and the Ge chip.

The present inventors have formed transparent conductive films of various compositions by a sputtering method, and the composition, structure, and
The characteristics as a transparent conductive film were examined. As a result, a transparent conductive film containing an oxide of In as a main component and containing Ge or containing Ge and Sn becomes an amorphous film, so that etching is easy and workability is improved. The present invention has a low electrical resistivity of 0.01 Ωcm or less and a high visible light transmittance of 80% or more, and is suitable as a transparent electrode of LCD. I came to.

The details will be described below.

Conventionally, IT used as a transparent conductive film
The conduction mechanism of O, that is, Sn-doped In ₂ O ₃ is as follows. That is, oxygen deficiency and Sn in In ₂ O ₃ form a composite defect and emit carrier electrons. Therefore, in order to increase the carrier density of ITO, an appropriate amount of oxygen vacancy is required. However, when the oxygen vacancy increases, the carrier mobility decreases. Therefore, it is necessary to leave an appropriate amount of oxygen vacancies in the film in order to minimize the electric resistivity.

Further, In and Sn are atoms whose atomic numbers are adjacent to each other, and their atomic radii are extremely close to 1.44 ° and 1.41 °, respectively. Therefore, even if In and Sn are substituted, the strain of the crystal is small. Therefore, a film formed by a sputtering method tends to be crystalline.

For ITO having the above properties,
In order to form an amorphous film, a low electric resistance film, or a high transmittance film, the following film forming method is appropriate, and it was necessary to adopt such a film forming method. That is, it is necessary to form a film at a low temperature in order to obtain an amorphous film. In order to obtain a film having a low electric resistance, it is necessary to use a high temperature and an appropriate oxygen partial pressure, e.g., 0.
It is necessary to form a film at about 0005 to 0.002 mTorr. Further, in order to obtain a high transmittance film, it is necessary to form the film at a high temperature under a high oxygen partial pressure.

Since the above-mentioned relationship exists between the film quality of the ITO film and the film forming method, it is difficult to form an amorphous film having a low electric resistance and a high transmittance. It was possible. For example, it is necessary to form a film at a low temperature in order to make the film amorphous, but when the film is formed at a low temperature, the electric resistance increases and the transmittance decreases. Further, when the film is formed under a high oxygen partial pressure in order to increase the transmittance, the electric resistivity further increases. Thus, it is difficult to obtain an amorphous transparent conductive film having a low electric resistance and a high transmittance by ITO,
It was impossible.

Therefore, the present inventors have studied the amorphousization of the In ₂ O ₃ film by adding an element different from Sn. As a result, it has been found that, under certain film formation conditions, the addition of Ge is effective for making the In ₂ O ₃ film amorphous, and does not impair the electrical resistivity and transmittance of the film.

That is, a Ge-doped In ₂ O ₃ film (Ge-doped In ₂ O ₃ film)
The carrier electrons in the ₃ film) are mainly electrons directly emitted by Ge, regardless of the oxygen vacancies in the In ₂ O ₃ film. Therefore, even if the amount of oxygen vacancies is freely changed, the electric resistance of the film is The resistivity does not change significantly, and the electrical resistivity does not increase even if the amount of oxygen vacancies is reduced.Therefore, the amount of oxygen vacancies can be reduced without losing the electrical resistivity, thereby increasing the high transmittance. I found that I can get it.

The atomic radius of Ge is as small as 1.22 °, which causes distortion in the crystal structure when forming a lattice with indium oxide (: In ₂ O ₃ ). Therefore, a certain amount of Ge is added,
If the film formation conditions are controlled, the crystal structure is easily broken and an amorphous film is formed. As a result, an amorphous film that could not be easily formed with the conventional Sn-added In ₂ O ₃ can be formed with the Ge-added In ₂ O ₃ film, and can be formed on a heated substrate (that is, without forming a low-temperature film). It was found that an amorphous film could be obtained. Then, it was confirmed that such an amorphous film was easily etched and had excellent workability.

The present invention has been completed based on the above findings, and the transparent conductive film according to the present invention is a transparent conductive film mainly containing an oxide of In and containing Ge. The structure of the film is made amorphous. Therefore, the transparent conductive film according to the present invention has a low electric resistivity and a high visible light transmittance, and is easily etched and excellent in workability.

Incidentally, the Ge-added In ₂ O ₃ film itself and the Ge-added
The TO film itself is conventionally known. For example,
No. 62-202415 discloses that Ge-doped ITO is deposited at 400 ° C.
A technique for forming a film is disclosed. However, the Ge-added ITO film described in this publication aims at eliminating film defects and the like, and is not intended to improve the etching property (that is, processability) as in the case of the present invention. There is no description of making a film amorphous or improving the etching property, and there is no description that the film can be made amorphous by adding Ge.

An amorphous film cannot be obtained simply by adding Ge as in the case of the Ge-added ITO film described in the above publication. No ITO film can be obtained. Etching is facilitated by forming an amorphous film as in the present invention. Therefore, it cannot be said that the Ge-added ITO film described in the above publication is easy to etch.

As described above, it is not possible to obtain an amorphous film simply by adding Ge, and it is not possible to obtain a film which can be easily etched. In order to obtain an amorphous film, it is necessary not only to add Ge but also to form a film under appropriate film forming conditions.

In addition, in order to obtain an amorphous film having a low electric resistivity and a high visible light transmittance, which is easy to be etched and has excellent workability, it is necessary to not only add Ge but also form an appropriate film. It is necessary to form a film under the conditions, and it is desirable to select the amount of Ge to be added. Details of the film forming conditions and the amount of Ge added will be described below.

When the film formation temperature is set to 100 to 300 ° C., the amount of Ge added is set to 2 to 12 atomic% with respect to the total amount of Ge and In, and the oxygen partial pressure is set to 0.02 mTorr or more, the electric resistance The rate is 0.
An amorphous transparent conductive film having a visible light transmittance of not less than 01 Ωcm and a transmittance of visible light of not less than 80% with respect to a film having a thickness of not less than 1000 mm can be formed. At this time, an amorphous transparent conductive film can be formed by setting the film forming speed to 45 ° / s or less. That is, the film formation temperature is 100 to 300 ° C., and the oxygen partial pressure in the atmosphere gas is 0.02 mTorr.
At the same time, the film formation rate is set to 45 ° / s or less, and the amount of Ge added to the total of Ge amount and In amount (hereinafter referred to as Ge added amount): , Electrical resistivity
An amorphous transparent conductive film having a visible light transmittance of not more than 0.01 Ωcm and a visible light transmittance of not less than 80% with respect to a film having a thickness of not less than 1000 mm can be obtained.

At this time, if the film formation temperature is less than 100 ° C. and the amount of Ge added is less than 2 atomic%, the decrease in the electric resistivity due to the emission of carrier electrons by Ge is not sufficient, and the electric resistivity is less than 0.01%.
It exceeds Ωcm. When the film formation temperature is less than 100 ° C. and the Ge content is more than 12 atomic%, an amorphous Ge-added In ₂ O ₃ film can be easily obtained, but the visible light transmittance is less than 80%.

When the film formation temperature is higher than 300 ° C., it is easy to obtain a film having an electric resistivity of 0.01 Ωcm or less, but it is difficult to make the film amorphous and it is necessary to add Ge which satisfies a visible light transmittance of 80% or more. Under the condition of an amount of 12 atomic% or less, the film does not become amorphous. Also, Ge
If the addition amount exceeds 12 atomic%, the visible light transmittance becomes less than 80%.

When the oxygen partial pressure is less than 0.02 mTorr, the visible light transmittance is reduced to less than 80%. That is, visible light transmittance:
To form an amorphous film of 80% or more, the oxygen partial pressure must be 0.02 mT
Must be greater than orr.

Thus, in the Ge-doped In ₂ O ₃ film,
Oxygen partial pressure during conventional ITO film formation (: 0.002 mTorr)
It has the property that the electrical resistivity does not decrease even if the film is formed under a high oxygen partial pressure (: 0.02 mTorr or more) which is 10 times or more higher than that of the high oxygen partial pressure. The film can be formed under such a high oxygen partial pressure. Therefore, the amorphous film having a high visible light transmittance can be obtained while maintaining a low electric resistivity without increasing the electric resistivity. A film can be formed. That is, under the conditions of a film forming temperature: 100 to 300 ° C., an added amount of Ge: 2 to 12 atomic%, an oxygen partial pressure: 0.02 mTorr or more, a visible light transmittance: 80% or more while maintaining the electrical resistivity. A crystalline film can be formed.

Ge addition amount: When Sn is added to a Ge-added In ₂ O ₃ film of _{2 to} 12 atomic%, Sn acts in a direction to increase the electric resistivity, and the Sn content is lower than the Sn amount and the In amount. When it is 4 atomic% or more with respect to the total, the electric resistivity becomes 0.01 Ωcm or more. If the Sn content is 5 atomic% or less, there is no effect on the amorphization.

Examples of the results of investigation of the etching characteristics of the amorphous transparent conductive film according to the present invention and the ITO film which is a conventional transparent conductive film will be described below. Note that the etching characteristics of the transparent conductive film are significantly different depending on the type of the etchant. In this study, the etching rate was measured using 60% nitric acid, one of the simplest etchants, as an etchant.

In the amorphous transparent conductive film according to the present invention, the film formed at a film forming temperature of 200 ° C. has an etching rate of 200 to 750 ° C./min and a film forming temperature of 20 ° C.
Etching rate: 200 to 900
Å / min. On the other hand, in the case of a conventional ITO film which is a transparent conductive film, a film formed at a film forming temperature of 200 ° C. cannot be etched with 60% nitric acid, and a film forming temperature of 20 ° C. The etching rate of the film is 80
Å / min. As described above, the amorphous transparent conductive film according to the present invention is more effective than the conventional transparent conductive film ITO film.
The etching characteristics (workability) are extremely excellent.

As described above, since the amorphous transparent conductive film according to the present invention has excellent characteristics, it can be suitably used as a transparent electrode of an LCD or a solar cell.

[0038]

[Example 1 (Experimental example 1)] A Ge chip (purity 99.99%) or a GeO ₂ chip (purity) on an In ₂ O ₃ target (purity 99.95%) as a sputtering target
99.9%) and a composite target in which Sn chips (purity 99.99%) or SnO ₂ chips (purity 99.9%) are installed in a predetermined amount, or an In ₂ O ₃ target containing a predetermined amount of Ge and Sn, A transparent conductive film was formed (deposited) on a glass substrate (Corning # 7059). The film forming conditions at this time are as follows.

Substrate temperature (film formation temperature) ---- 200.degree. C. Atmospheric gas -------------- 2.0% O ₂ containing Ar atmosphere gas pressure --------- --- 2mTorr Power -------------------- 3.0W / cm ² Deposition rate ---------------- 40Å / Sec

The X-ray diffraction pattern of the transparent conductive film obtained by the above film formation was measured with an X-ray diffraction apparatus. FIG. 1 shows an X-ray diffraction pattern as a result. It can be seen that the structure of the film is amorphous.

The specific resistance (electrical resistivity) was measured by a four-terminal (probe) method, and the visible light transmittance was measured by a self-recording spectrophotometer. Etching was performed using 60% nitric acid, and the etching rate was measured. Table 1 shows the results.

Example 2 (Experimental Example 2) In ₂ O ₃ target (purity 99.95%) as a sputtering target
A Ge target (purity 99.99%) or a GeO ₂ chip (purity 99.9%) is mounted on the target in a predetermined amount.
A transparent conductive film was formed on a glass substrate using an In ₂ O ₃ target containing a predetermined amount of The film forming conditions at this time are as follows.

Substrate temperature (film formation temperature) ---- 200.degree. C. Atmospheric gas -------------- 2.0% O ₂ containing Ar atmosphere gas pressure --------- --- 2mTorr Power -------------------- 4.5 W / cm ² Deposition rate ---------------- 25Å / Sec

The X-ray diffraction pattern of the transparent conductive film obtained by the above film formation was measured in the same manner as in Example 1. FIG. 1 shows an X-ray diffraction pattern as a result.
It can be seen that the structure of the film is amorphous.

In the same manner as in Example 1, the specific resistance (electrical resistivity), the visible light transmittance, and the etching rate were measured. Table 1 shows the results.

Example 3 (Experimental Example 3) A transparent conductive film was formed on a similar glass substrate using the same sputtering target as in Example 2. The film forming conditions at this time are as follows.

Substrate temperature (deposition temperature) ---- 200.degree. C. Atmosphere gas -------------- 2.0% O ₂ containing Ar atmosphere gas pressure --------- ---- 4mTorr power -------------------- 4.5 W / cm ² Deposition rate ---------------- 25Å / Sec

The X-ray diffraction pattern of the transparent conductive film obtained by the film formation was measured in the same manner as in Example 1. FIG. 1 shows an X-ray diffraction pattern as a result.
It can be seen that the structure of the film is amorphous.

In the same manner as in Example 1, the specific resistance (electrical resistivity), visible light transmittance, and etching rate were measured. Table 1 shows the results.

Example 4 (Experimental Example 4) Using the same sputtering target as in Example 2, a transparent conductive film was formed on a similar glass substrate. The film forming conditions at this time are as follows.

Substrate temperature (film formation temperature) ---- 200.degree. C. Atmospheric gas -------------- 2.0% O ₂ containing Ar gas pressure --------- --- 2mTorr power -------------------- 4.5 W / cm ² Deposition rate ---------------- 40Å / Sec

The X-ray diffraction pattern of the transparent conductive film obtained by the above film formation was measured in the same manner as in Example 1. FIG. 1 shows an X-ray diffraction pattern as a result.
It can be seen that the structure of the film is amorphous.

Further, the specific resistance (electrical resistivity), the visible light transmittance, and the etching rate were measured in the same manner as in Example 1. Table 1 shows the results.

Example 5 (Experimental Example 5) A transparent conductive film was formed on a similar glass substrate using the same sputtering target as in Example 2. The film forming conditions at this time are as follows.

Substrate temperature (deposition temperature) ---- 300.degree. C. Atmospheric gas -------------- 4.0% O ₂ containing Ar atmosphere gas pressure --------- --- 0.5mTorr Power -------------------- 4.5 W / cm ² Deposition rate ---------------- 25Å / sec

The X-ray diffraction pattern of the transparent conductive film obtained by the above film formation was measured in the same manner as in Example 1. FIG. 1 shows an X-ray diffraction pattern as a result.
It can be seen that the structure of the film is amorphous.

In the same manner as in Example 1, the specific resistance (electrical resistivity), visible light transmittance, and etching rate were measured. Table 1 shows the results.

Example 6 (Experimental Example 6) A transparent conductive film was formed on a similar glass substrate using the same sputtering target as in Example 2. The film forming conditions at this time are as follows.

Substrate temperature (film formation temperature) ---- 100 ° C. Atmosphere gas -------------- 2.0% O ₂ containing Ar atmosphere gas pressure --------- --- 3mTorr power -------------------- 4.5 W / cm ² Deposition rate ---------------- 40Å / Sec

The X-ray diffraction pattern of the transparent conductive film obtained by the film formation was measured in the same manner as in Example 1. FIG. 1 shows an X-ray diffraction pattern as a result.
It can be seen that the structure of the film is amorphous.

In the same manner as in Example 1, the specific resistance (electrical resistivity), the visible light transmittance, and the etching rate were measured. Table 1 shows the results.

Example 7 (Experimental Example 7) A transparent conductive film was formed on the same glass substrate using the same sputtering target as in Example 2. The film forming conditions at this time are as follows.

Substrate temperature (deposition temperature) ---- 20 ° C. Atmospheric gas -------------- 2.0% O ₂ containing Ar atmosphere gas pressure --------- --- 3mTorr power -------------------- 2.0 W / cm ² Deposition rate ---------------- 40Å / Sec

The X-ray diffraction pattern of the transparent conductive film obtained by the above film formation was measured in the same manner as in Example 1. FIG. 1 shows an X-ray diffraction pattern as a result.
It can be seen that the structure of the film is amorphous.

The specific resistance (electrical resistivity), the visible light transmittance, and the etching rate were measured in the same manner as in Example 1. Table 1 shows the results.

Comparative Example 1 (Experimental Example 8) In ₂ O ₃ target (purity: 99.95%) as a sputtering target
A composite target in which a predetermined amount of Sn chips (purity 99.99%) or SnO ₂ chips (purity 99.9%) are set on top, or Sn
A transparent conductive film was formed on a glass substrate using an In ₂ O ₃ target containing a predetermined amount of The film forming conditions at this time are as follows.

Substrate temperature (film formation temperature) ---- 200.degree. C. Atmospheric gas -------------- Ar atmosphere gas pressure containing 0.1% O ₂ --------- --- 1mTorr power -------------------- 2.0 W / cm ² deposition rate ---------------- 12Å / Sec

The X-ray diffraction pattern of the transparent conductive film obtained by the above film formation was measured in the same manner as in Example 1. FIG. 1 shows an X-ray diffraction pattern as a result.
It can be seen that the structure of the film is not amorphous but crystalline.

The specific resistance (electrical resistivity), visible light transmittance, and etching rate were measured in the same manner as in Example 1. Table 1 shows the results.

Comparative Example 2 (Experimental Example 9) Using the same sputtering target as in Comparative Example 1, a transparent conductive film was formed on a similar glass substrate. The film forming conditions at this time are as follows.

Substrate temperature (deposition temperature) ---- 20 ° C. Atmospheric gas -------------- 0.1% O ₂ containing Ar atmosphere gas pressure --------- --- 1mTorr power -------------------- 2.0 W / cm ² deposition rate ---------------- 12Å / Sec

The X-ray diffraction pattern of the transparent conductive film obtained by the film formation was measured in the same manner as in Example 1. As a result, it was confirmed that the structure of the film was not amorphous but crystalline.

The specific resistance (electrical resistivity), visible light transmittance, and etching rate were measured in the same manner as in Example 1. Table 1 shows the results.

Comparative Example 3 (Experimental Example 10) A transparent conductive film was formed on the same glass substrate using the same sputtering target as in Example 2. The film forming conditions at this time are as follows.

Substrate temperature (film formation temperature) ---- 20 ° C. Atmospheric gas -------------- 2.0% O ₂ containing Ar atmosphere gas pressure --------- --- 1mTorr power -------------------- 2.0 W / cm ² deposition rate ---------------- 25Å / Sec

The X-ray diffraction pattern of the transparent conductive film obtained by the above film formation was measured in the same manner as in Example 1. As a result, it was confirmed that the structure of the film was not amorphous but crystalline.

Further, in the same manner as in Example 1, the specific resistance (electrical resistivity), the visible light transmittance, and the etching rate were measured. Table 1 shows the results.

Comparative Example 4 (Experimental Example 11) A transparent conductive film was formed on the same glass substrate using the same sputtering target as in Example 2. The film forming conditions at this time are as follows.

Substrate temperature (film formation temperature) ---- 20 ° C. Atmospheric gas -------------- 2.0% O ₂ containing Ar atmosphere gas pressure --------- --- 1mTorr power -------------------- 2.0 W / cm ² deposition rate ---------------- 25Å / Sec

The X-ray diffraction pattern of the transparent conductive film obtained by the above film formation was measured in the same manner as in Example 1. As a result, it was confirmed that the structure of the film was amorphous.

In the same manner as in Example 1, the specific resistance (electrical resistivity), the visible light transmittance, and the etching rate were measured. Table 1 shows the results.

[0082]

[Table 1]

[0083]

The transparent conductive film according to the present invention has the above-mentioned structure and functions, has a low electric resistivity and a high visible light transmittance, is easily etched, and has excellent workability. It is an amorphous transparent conductive film that can be suitably used as a transparent electrode such as a display electrode of a thin film transistor type liquid crystal display. It is possible to obtain a remarkable effect that high functionality and quality can be improved.

[Brief description of the drawings]

FIG. 1 is an X-ray diffraction diagram of a transparent conductive film and glass of a substrate according to Examples and Comparative Examples.

Claims (6)

[Claims] 1. A transparent conductive film having excellent workability, characterized by being a transparent conductive film containing an oxide of In as a main component and containing Ge and having an amorphous structure. 2. The transparent conductive film having excellent workability according to claim 1, which contains Sn. 3. The transparent conductive film excellent in processability according to claim 2, wherein the content of Sn is 5 atomic% or less with respect to the total of Sn content and In content. 4. The transparent conductive film excellent in processability according to claim 1, wherein the content of Ge is 2 to 12 atomic% with respect to the total of the amount of Ge and the amount of In. 5. The visible light transmittance is 80% or more, and the electric resistivity is
The transparent conductive film excellent in processability according to claim 1, 2, 3, or 4 having a resistivity of 0.01 Ω · cm or less. 6. The transparent conductive film according to claim 1, which is used as a transparent electrode of a liquid crystal display.