JPH02155111A - Tin oxide-based electrically conductive film - Google Patents

Abstract

PURPOSE:To lower specific resistance without degrading light transmissivity by replacing a part of Sn in a composition of mainly SnO2 with Zr and Sb. CONSTITUTION:A compound of the title film has a formula (I) where 1.80<w<2.05; 0.001<x<0.030; and 0.015<y<0.020. In the case that x is out of the defined range or y is <=0.015, the specific resistance of the film becomes large, and when y is >=0.020, light transmissivity becomes <=70%. Also, when w is <=1.80, SnO is formed in the film and light transmissivity of the film is lowered and there is no compound which has w>=2.05. As a result, a conductive film with low specific resistance without degrading light transmissivity is obtained.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a tin oxide-based electrically conductive film.

(Prior art) Conventionally, as this type of tin oxide-based electrically conductive film, 5n02
film or ITO (Indium-Tin-Oxi)
de) membranes are known. Because these thin films have excellent electrical conductivity and optical transparency, they are often used as transparent electrodes in solar cells, electrochromic devices, liquid crystal display devices, etc. by forming them on the surface of transparent substrates. ing.

Among the tin oxide-based electrically conductive films, the former 5N02 film has higher hardness than the latter ITO film and is less likely to be scratched, making it easier to handle, and has excellent heat resistance.
Although it has the advantage that the resistivity does not increase much due to the heating applied when depositing other thin film materials on the N02 film, on the other hand, the electrical conductivity is significantly lower than that of the ITO film. It had the disadvantage of being small.

Therefore, in order to improve the electrical conductivity of the 5n02 film, that is, to lower the specific resistance, sb or F is added to the 5n02 film. The addition of sb or F to 5n02 increases the concentration of conduction electrons inside the 5n02 film, and in addition to the addition of sb or F, 51102
In order to reduce the influence of grain boundaries that impede the movement of conduction electrons, holes, etc. in the grain boundary portion of the film, the deposition rate and deposition temperature conditions when depositing the SnO□ film are adjusted. The crystal grain size of the 5n02 film is selectively increased.

(Problem to be Solved by the Invention) However, the resistivity of the 5n02 film can be lowered by adding sb or F to 5n02, but if the amount of these components added to Sn exceeds 2%, the
Since the light transmittance of the nO□ film is significantly reduced, there is a limit to the ability to reduce the specific resistance while maintaining good light transmittance. For example, a 5n02 film obtained by adding 2.0 mol% of sb to 5n02, forming a film under the best conditions with a film-forming rate of 1.2 people/second and a film-forming (substrate) temperature of 450°C. The specific resistance is 3.5 Xl0-'Ωcm, the light transmittance is 70%, and the specific resistance of the 5n02 film is 1.5 to 1.5 to that of the ITO film.
2.2 There is a problem that it is still large compared to the mark Xl0-'Ωφ.

An object of the present invention is to provide a tin oxide-based electrically conductive film with reduced specific resistance without impairing light transmittance.

(Means for Solving the Problems) In order to achieve the above object, the present inventors conducted extensive research on tin oxide-based electrically conductive films, and as a result, they replaced a portion of Sn in a composition consisting of 5n02 with Zr and sb. It has been found that by doing so, the specific resistance can be lowered without impairing the light transmittance.

Furthermore, by substituting a part of Sn in the composition consisting of 5n02 with Zr and substituting a part of O in the composition with F, it was found that the specific resistance was reduced without impairing the light transmittance. I recognized it.

The present invention has been made based on the above findings, and includes:
The first invention relates to a tin oxide-based electrically conductive film in which a part of Sn in the composition is replaced with Z' and sb, and has the general formula % where 1.80 < w < 2.05 0.001 < x < 0.030 0.015 < y < 0.020.

The composition ratio (
Set the x(7) value at Sn + y - 1) to 0.0
The reason for setting the value to be 01 to 0.030 is that when the value of X is outside this range, the specific resistance becomes large.

Also, the value of y in the composition ratio of sb is 0.015 to 0,0
The reason for setting it to 20 is that when the value of y is 0.015 or less, the specific resistance is large, and when the value of y is 0.020 or more, the light transmittance is 70% or less.

In addition, the W value of O was set to 1.80 to 2.05 because if the W value is less than 1.80, SnO will be generated in the film and the light transmittance will decrease. This is because there are no cases with a value of .05 or higher.

Further, the second invention relates to a tin oxide-based electrically conductive film in which a part of Sn in the composition is replaced with Zr and a part of O in the composition is replaced with F, and the film has the general formula %. % However, it is characterized by having a composition expressed as 1.80<w<2.05 0.003<x<0.030 0.015<z<0.020.

Composition ratio of Zr (
The value of
The reason for setting the value to 30 is that when the value of X is out of this range, the specific resistance becomes large.

In addition, the composition ratio of F (0+z-1,80
~2.05) 0.015~0.020
The reason for this is that when the value of 2 is 0.015 or less, the specific resistance is large, and when the value of 2 is 0.020 or more, the light transmittance is 70% or less.

(Function) By substituting a part of Sn in Sn0w with Zr,
Growth of 5no2 crystal grains is promoted. Furthermore, 4 (il
By replacing a portion of Sn in the Ii metal with sb, a pentavalent metal, the concentration of conduction electrons in the film increases.

Furthermore, by replacing some of the 02- ions in Sn0w with F- ions, the concentration of conduction electrons in the film increases.

(Example) Next, the tin oxide-based electrically conductive film of the present invention will be described based on Examples.

First, specific examples of the present invention will be described together with comparative examples regarding the case of a tin oxide-based electrically conductive film in which a portion of Sn in the composition is replaced with 2'' and sb.

As an example, a light-transmitting glass substrate (No. 7059 manufactured by Conning Corporation) was first cleaned with acetone and further cleaned with methanol, and then placed in a film formation chamber of a CVD apparatus maintained at a temperature of 450°C. Next, the raw material Z r Cis
,5bCj! The CV
The film was supplied to the film forming chamber of the D apparatus at a film forming rate of 1.2 people/second, and a film was deposited on a light-transmitting glass substrate to a thickness of 2,000 yen.
After forming a tin oxide-based electrically conductive film and forming these as Examples 1 to 9, and forming a tin oxide-based electrically conductive film with a thickness of 2000, the liquid film was further heated at a temperature of 450°C in an oxygen atmosphere.
Example 10 was annealed for 30 minutes, and after forming a tin oxide-based electrically conductive film with a thickness of 2000 mm, the liquid film was further heated in a reducing atmosphere of 98% nitrogen gas and 2% hydrogen gas. Example 11 was obtained by annealing at a temperature of 300° C. for 30 minutes.

Next, as a comparative example, ZrCj! 4.5b Tin oxide-based electrically conductive films were formed in the same manner as in the previous example except that CJj, SnC, and N20 were mixed in the ratios shown in Table 1, and these were used as Comparative Examples 1 to 6. .

The tin oxide-based electrically conductive films of Examples No. 1 to 11 and Comparative Examples No. 1 to No. 6 were subjected to elemental analysis using a fluorescent X-ray analyzer to examine the composition ratio of the films, and the crystal grain size of the liquid film was measured using a scanning electron beam analyzer. When investigated by microscopic (SEM) photography, the results shown in Table 1 were obtained.

Furthermore, an etching resist containing Butyl Celsolve as a main component was coated in a predetermined shape on the surface of the tin oxide-based electrically conductive film on each of the light-transmitting glass substrates of Examples 1 to 11 and Comparative Examples 1 to 6 by a screen printing method. After drying at 120°C for 10 minutes, this was mixed with 3526 hydrochloric acid and 4
After immersing for 10 minutes in an etching solution consisting of a 5% iron chloride aqueous solution and pure water at a mixing ratio of 2:1:4, the sample was thoroughly washed with water and the remaining etching resist was removed with acetone.
A tin oxide-based electrically conductive film (2) in a circular pattern with cuts on all sides as shown on a light-transmitting glass substrate (1).
A sample for resistivity measurement was formed, and lead wires (3) were soldered to predetermined positions A, B, C, and D of the formed sample for resistivity measurement, respectively. Then, after measuring the voltage [D, (V)] between the CD terminals with the DC current [11] flowing between the AB terminals of each resistivity 151 constant sample, the DC current [D, (V)] between the BC terminals was similarly measured. The voltage [D2 (V)] between the AD terminals was measured with 11 flowing, and the specific resistance [ρ (Ω・(to)) was investigated using the following formula, and the results shown in Table 1 were obtained. It was done.

However, d: film thickness, I -500 μA.

In addition, the tin oxide-based electrically conductive film on each of the light-transmitting glass substrates of Examples FQ1 to FQ11 and Comparative Examples FQ to FQ6 was coated with a wavelength λ-
When visible light of 0.5 pm was irradiated and the light transmittance (%) was examined, the results shown in Table 1 were obtained.

Next, specific examples of the present invention will be described together with comparative examples regarding the case of a tin oxide-based electrically conductive film in which a part of Sn in the composition is replaced with Zr and a part of O in the composition is replaced with F. explain.

As an example, a light-transmitting glass substrate (No. 7059 manufactured by Conning Corporation) was first cleaned with acetone and further cleaned with methanol, and then placed in a film formation chamber of a CVD apparatus maintained at a temperature of 450°C. Next, the raw materials ZrC, NH
After mixing 2F, SnC, and N20 with N2 as a carrier gas, and further mixing the respective raw material gases so as to have various composition ratios shown in Table 2, the film was deposited in the film formation chamber of the CVD apparatus. A tin oxide-based electrically conductive film was formed on a light-transmissive glass substrate with a thickness of 2000 m/s by supplying the film at a film speed of 1.2 m/sec, and these were named Examples 12 to 19. After forming a 2,000-layer tin oxide-based electrically conductive film, the wave film was further heated at a temperature of 450°C in an oxygen atmosphere.
Example 20 was annealed for 30 minutes, and after forming a tin oxide electrically conductive film with a thickness of 2000 mm, the wave film was further treated in a reducing atmosphere of 98% nitrogen gas and 2% hydrogen gas. Example 21 was obtained by annealing at a temperature of 300° C. for 30 minutes.

Next, as a comparative example, ZrC, NH2F, 5nCj
! Comparative Examples 7 to 11 were obtained by forming tin oxide-based electrically conductive films in the same manner as in the example above, except that 4 and N20 were mixed in the ratios shown in Table 2.

Then, the composition ratio, crystal grain size, When the specific resistance and light transmittance were investigated, Table 2
The results shown are obtained.

As is clear from Table-1 and Table-2, the Sn of the present invention
Examples 1 to 11 in which a part of Sn was replaced with Zr and sb, and Examples 12 to 21 in which a part of Sn was replaced with 2'' and a part of 0 was replaced with F.
The tin oxide-based electrically conductive film had high light transmittance and low specific resistance.

In contrast, the tin oxide-based electrically conductive films of Comparative Examples 1 to 6 in which the composition ratio of Zr and sb was outside the range of the composition ratio of the present invention,
Comparative Example 7 in which the composition ratio of 2' and F is outside the range of the composition ratio of the present invention
Although the tin oxide-based electrically conductive films of Nos. 1 to 11 had high light transmittance, the specific resistance remained large without decreasing. This is considered to be because the content of 2' exceeds the 2 which can be substituted by Sn, causing partial segregation of Zr in the crystal of 5n02, which impedes the movement of conduction electrons and hole carriers.

Furthermore, as is clear from Tables 1 and 2, Zr relative to Sn
It was confirmed that the grain size of 5n02 increases as the amount of substitution increases.

(Effects of the Invention) In this way, according to the present invention, since a part of Sn in Sn0w is replaced with Zr, the crystal grain size of Snow can be increased, and furthermore, part of Sn can be replaced with Zr. s
By replacing it with b, we were able to increase the conduction electron concentration in the film, and by replacing some of the O in Sn0w with F, we were able to increase the conduction electron concentration in the film. Therefore, it is possible to obtain a small specific resistance without impairing light transmittance, and it is possible to provide a tin oxide-based electrically conductive film having excellent electrical conductivity.

[Brief explanation of the drawing]

The drawing is a perspective view showing a method for measuring the specific resistance of a tin oxide-based electrically conductive film. 1...Light-transparent glass substrate 2...Tin oxide-based electrically conductive film 3...Outside lead wire 3''6

Claims (1)

[Claims] 1. General formula [Sn_1_-_x_-y・Zr_x・Sb_Y]O_
A tin oxide-based electrically conductive film characterized by having a composition as follows: w, 1.80<w<2.05, 0.001<x<0.030, 0.015<y<0.020. 2. General formula [Sn_1_-_x・Zr_x]O_w_-_z・F_
A tin oxide-based electrically conductive film characterized by having a composition as follows: z, 1.80<w<2.05, 0.003<x<0.030, 0.015<z<0.020.