TCO film and preparation method thereof

Abstract

The invention belongs to the technical field of production of electro-permeable films, and discloses a preparation method of a TCO film, which comprises the following steps: depositing indium cerium oxide on the surface of a glass substrate to obtain a glass substrate plated with indium cerium oxide, and annealing the glass substrate in an environment of 100-500 DEG C for 5-30 minutes to obtain the TCO film. According to the method, the annealing temperature and the annealing time of the TCO thin film in the annealing process are optimized, so that the defect number of the TCO thin film is reduced, the lower defect number means that the density of the thin film and the uniformity and stability of the internal structure are improved, and therefore the carrier mobility of the TCO thin film is greatly improved after annealing, and the performance of the TCO thin film is improved. Therefore, the conductivity of the TCO thin film is improved, the resistivity is reduced, and in addition, the invention further discloses the TCO thin film.

Description

Technical Field

[0001] The present application relates to the technical field of electrically permeable film production, and in particular to a TCO film and a preparation method thereof. Background Art

[0002] TCO (transparent conductive oxide) film is an important component of thin-film solar cells. It has high light transmittance and low resistivity in the visible light wavelength range. High light transmittance in the visible spectrum region is conducive to improving the conversion efficiency of photovoltaic cells. It is conducive to improving the photoelectric conversion efficiency and reducing energy loss. The performance of TCO film has an important influence on the efficiency and life of thin-film solar cells. Therefore, the research and optimization of TCO film is one of the keys to improving the performance of thin-film solar cells.

[0003] Studies have shown that annealing in an oxygen-containing atmosphere can significantly improve the degree of crystallization of transparent conductive films, reduce the surface roughness of the films and increase the transmittance of the films, but it will also deteriorate the conductive properties of the films; annealing can improve the conductive properties of the films and increase the surface roughness of the films; the atmosphere of inert gases such as argon and nitrogen can improve the crystallinity of TCO transparent conductive films and reduce the surface roughness of the films.

[0004] Chinese patent application 202111156884.6 discloses a high-mobility transparent conductive oxide film and a preparation method thereof. The TCO film is grown by reactive radio frequency magnetron sputtering to grow tellurium- and scandium-co-doped indium oxide TCO films at room temperature. The sputtering targets are indium target, tellurium target, and scandium target. The sputtering working gas is argon and the reaction gas is oxygen. Before the TCO film grows, only argon is introduced into the sputtering chamber, and the three targets are pre-sputtered for 15-30 minutes to remove the adsorbed on the surface of the target. Impurities and surface oxides. When the TCO film begins to grow, argon and oxygen are fully mixed in the mixing chamber and then enter the sputtering chamber. The flow ratio of argon to oxygen is 50:1-20:1, and the sputtering pressure is 0.1-0.4Pa. The sputtering power of the indium target is 200W, the sputtering power of the tellurium target is 20-30W, and the sputtering power of the scandium target is 1-2W. The substrate deposition temperature is room temperature, and the sputtering time is 10-20min. The film prepared by this scheme has the characteristics of high carrier mobility and low resistivity.

[0005] Further observation of the description of the scheme shows that the scheme states in paragraph 5 of the description: "Indium oxide (In 2 O 3) is doped with tellurium (Te), the probability of the lowest conduction band of indium oxide overlapping with the related orbit of tellurium doping is very small. Therefore, the probability of electrons in tellurium-doped indium oxide being scattered by the doped impurity atoms is very low, the mean free path time of electrons is long, the effective mass of electrons is small and the correlation with the carrier concentration is weak. In addition, with 80 pm tin ions (Sn 4 + ) radius, the 97pm tellurium ion (Te 4+ ) has a radius closer to that of the indium ion (In 3+ ) radius (94pm), so tellurium doping greatly reduces the lattice strain caused by the doped atoms. At the same time, tellurium doping reduces the concentration of oxygen vacancies, making the scattering of impurities by oxygen vacancies lower. Therefore, the tellurium-doped indium oxide TCO film has high carrier mobility, low resistivity, and high light transmittance, which is mainly attributed to the low impurity scattering of tellurium dopants and oxygen vacancies. "It can be seen that this scheme is more about reducing the defects of the material caused by doping by changing the doping elements in the TCO film, thereby improving the conductivity of the TCO.

[0006] The problem to be solved by this solution is: how to provide a method for preparing a TCO thin film that is different from the prior art and can prepare a TCO thin film with good electrical properties. Summary of the invention

[0007] The purpose of this application is to provide a method for preparing a TCO film with good electrical properties. This application aims to reduce the number of defects in the TCO film by optimizing the annealing temperature and annealing time of the TCO film during the annealing process, thereby improving the conductivity of the TCO film and reducing the resistivity.

[0008] To achieve the above object, the present application discloses a method for preparing a TCO film, comprising the following steps:

[0009] Step 1: depositing cerium indium oxide onto the surface of a glass substrate to obtain a glass substrate coated with cerium indium oxide;

[0010] Step 2: annealing the glass substrate coated with indium cerium oxide in an environment of 100 to 500° C. for 5 to 30 minutes to obtain a TCO film.

[0011] Preferably, step 2 specifically includes: placing the glass substrate coated with cerium indium oxide in an environment of 200 to 300° C. and annealing for 5 to 30 minutes to obtain a TCO film.

[0012] Preferably, step 1 includes the following sub-steps:

[0013] Step A1: cleaning the glass substrate, and then placing the cleaned glass substrate and the indium cerium oxide target into a preset position of the sputtering chamber;

[0014] Step A2: Adjust the vacuum degree of the sputtering chamber to 5.2×10 -6 ~7.7×10 -6 torr, and then a mixed gas of argon, oxygen and hydrogen was introduced into the sputtering chamber and the vacuum degree of the sputtering chamber was adjusted to 2.5×10 -3 ~5.2×10 -3 torr;

[0015] Step A3: sputtering and depositing the indium cerium oxide in the indium cerium oxide target onto the surface of the glass substrate to obtain a glass substrate coated with indium cerium oxide.

[0016] Preferably, the mixed gas includes a mixed gas 1 of argon and oxygen and a mixed gas 2 of argon and hydrogen, and the flow ratio of the mixed gas 1 to the mixed gas 2 is 10-20:80-90;

[0017] In the mixed gas 1, the mass ratio of argon to oxygen is 90-99:1-10;

[0018] In the mixed gas 2, the mass ratio of argon to hydrogen is 90-99:1-10.

[0019] Preferably, in step A1, the distance between the glass substrate and the indium cerium oxide target is 45 mm to 100 mm.

[0020] Preferably, step A3 specifically comprises: sputtering and depositing indium cerium oxide in the indium cerium oxide target onto the surface of the glass substrate at a sputtering power of 810 to 1430 W for a sputtering time of 5 to 10 minutes to obtain a glass substrate coated with indium cerium oxide.

[0021] In addition, the present application also discloses a TCO film, which is prepared by the above-mentioned TCO film preparation method.

[0022] The beneficial effects of this application are:

[0023] The present application optimizes the annealing temperature and annealing time of the TCO film during the annealing process, thereby reducing the number of defects in the TCO film. A lower number of defects means that the density of the film and the uniformity and stability of the internal structure are improved. Therefore, the present application greatly improves the carrier mobility of the TCO film after annealing, thereby improving the conductivity of the TCO film and reducing the resistivity. DETAILED DESCRIPTION

[0024] The present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. In the description of the present invention, it should be noted that, if no specific conditions are specified in the embodiments, the conditions are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0025] Example 1

[0026] Step 1:

[0027] Step A1: clean the glass substrate, and then place the cleaned glass substrate and the indium cerium oxide target into a sputtering chamber with a distance of 80 mm between the glass substrate and the indium cerium oxide target;

[0028] Step A2: Adjust the vacuum degree of the sputtering chamber to 6.5×10 -6 torr, then a mixed gas of argon, oxygen and hydrogen was introduced into the sputtering chamber and the vacuum degree of the sputtering chamber was adjusted to 4.0×10 -3 torr;

[0029] The mass ratio of argon, oxygen and hydrogen in the mixed gas is 118.75:1.25:5;

[0030] Step A3: sputtering and depositing indium cerium oxide in the indium cerium oxide target onto the surface of the glass substrate at a sputtering power of 1000 W for 8 minutes to obtain a glass substrate coated with indium cerium oxide;

[0031] Step 2: anneal the glass substrate coated with cerium indium oxide at 300° C. for 20 minutes to obtain a TCO film.

[0032] Example 2

[0033] Step 1:

[0034] Step A1: clean the glass substrate, and then place the cleaned glass substrate and the indium cerium oxide target into a sputtering chamber with a distance of 45 mm between the glass substrate and the indium cerium oxide target;

[0035] Step A2: Adjust the vacuum degree of the sputtering chamber to 5.2×10 -6 torr, and then a mixed gas of argon, oxygen and hydrogen was introduced into the sputtering chamber and the vacuum degree of the sputtering chamber was adjusted to 2.5×10 -3 torr;

[0036] The mass ratio of argon, oxygen and hydrogen in the mixed gas is 123.75:0.25:1;

[0037] Step A3: sputtering and depositing indium cerium oxide in the indium cerium oxide target onto the surface of the glass substrate at a sputtering power of 810 W for a sputtering time of 5 min to obtain a glass substrate coated with indium cerium oxide;

[0038] Step 2: anneal the glass substrate coated with indium cerium oxide at 100° C. for 5 minutes to obtain a TCO film.

[0039] Example 3

[0040] Step 1:

[0041] Step A1: clean the glass substrate, and then place the cleaned glass substrate and the indium cerium oxide target into a sputtering chamber with a distance of 100 mm between the glass substrate and the indium cerium oxide target;

[0042] Step A2: Adjust the vacuum degree of the sputtering chamber to 7.7×10 -6 torr, and then a mixed gas of argon, oxygen and hydrogen was introduced into the sputtering chamber and the vacuum degree of the sputtering chamber was adjusted to 5.2×10 -3 torr;

[0043] The mass ratio of argon, oxygen and hydrogen in the mixed gas is 112.5:2.5:10;

[0044] Step A3: sputtering and depositing indium cerium oxide in the indium cerium oxide target onto the surface of the glass substrate at a sputtering power of 1430 W for a sputtering time of 10 min to obtain a glass substrate coated with indium cerium oxide;

[0045] Step 2: anneal the glass substrate coated with indium cerium oxide at 500° C. for 30 minutes to obtain a TCO film.

[0046] Example 4

[0047] The method is basically the same as Example 1, except that the glass substrate coated with cerium indium oxide is annealed at 230° C. for 20 minutes to obtain a TCO thin film.

[0048] Example 5

[0049] The method is basically the same as Example 1, except that the glass substrate coated with cerium indium oxide is annealed at 280° C. for 20 minutes to obtain a TCO thin film.

[0050] Example 6

[0051] The method is basically the same as Example 1, except that in step A2, the mixed gas includes a mixed gas 1 of argon and oxygen and a mixed gas 2 of argon and hydrogen, and the flow ratio of the mixed gas 1 to the mixed gas 2 is 20:80;

[0052] In the mixed gas 1, the mass ratio of argon to oxygen is 95:5;

[0053] In the mixed gas 2, the mass ratio of argon to hydrogen is 95:5.

[0054] Comparative Example 1

[0055] Step A1: clean the glass substrate, and then place the cleaned glass substrate and the indium cerium oxide target into a sputtering chamber with a distance of 80 mm between the glass substrate and the indium cerium oxide target;

[0056] Step A2: Adjust the vacuum degree of the sputtering chamber to 6.5×10 -6 torr, then a mixed gas of argon, oxygen and hydrogen was introduced into the sputtering chamber and the vacuum degree of the sputtering chamber was adjusted to 4.0×10 -3 torr;

[0057] The mass ratio of argon, oxygen and hydrogen in the mixed gas is 118.75:1.25:5;

[0058] Step A3: sputtering and depositing the indium cerium oxide in the indium cerium oxide target onto the surface of the glass substrate at a sputtering power of 1000 W for 8 minutes to obtain a TCO film.

[0059] Comparative Example 2

[0060] The method is substantially the same as Comparative Example 1, except that, in step A2, the mixed gas includes a mixed gas 1 of argon and oxygen and a mixed gas 2 of argon and hydrogen, and the flow ratio of the mixed gas 1 to the mixed gas 2 is 20:80;

[0061] In the mixed gas 1, the mass ratio of argon to oxygen is 95:5;

[0062] In the mixed gas 2, the mass ratio of oxygen to hydrogen is 95:5.

[0063] Performance Test:

[0064] Electrical performance test: Use the Hall effect instrument to test, use the standard sample to calibrate and verify the equipment, and test the sample after the test data reaches the standard sample. The specific test results are shown in Table 1:

[0065] Table 1

[0066] Group <![CDATA[Carrier concentration / cm-3 3 > <![CDATA[Mobility / cm 2 / (V·s)]]> <![CDATA[Resistivity / Ω / cm 3 > Example 1 <![CDATA[4.47×10 20 ]]> 52.39 <![CDATA[2.67×10 -4 ]]> Example 2 <![CDATA[4.15×10 20 ]]> 51.25 <![CDATA[2.94×10 -4 ]]> Example 3 <![CDATA[3.78×10 20 ]]> 50.03 <![CDATA[3.30×10 -4 ]]> Example 4 <![CDATA[4.88×10 20 ]]> 52.42 <![CDATA[2.44×10 -4 ]]> Example 5 <![CDATA[4.65×10 20 ]]> 53.01 <![CDATA[2.53×10 -4 ]]> Example 6 <![CDATA[5.02×10 20 ]]> 61.48 <![CDATA[2.02×10 -4 ]]> Comparative Example 1 <![CDATA[5.14×10 20 ]]> 17.72 <![CDATA[6.86×10 -4 ]]> Comparative Example 2 <![CDATA[5.19×10 20 ]]> 17.83 <![CDATA[6.75×10 -4 ]]>

[0067] Result analysis:

[0068] 1. It can be seen from Examples 1-3 that after a small adjustment of the process parameters in the preparation of the TCO film, the resistivity of the TCO film obtained in Examples 1-3 shows a certain fluctuation trend, but the fluctuation range is relatively small;

[0069] 2. It can be seen from Examples 1 and 4-5 that after further adjusting the temperature during the annealing process, the resistivity of Example 4-5 is significantly improved relative to that of Example 1. It can be seen that the annealing temperature of Example 4-5 is more advantageous, and the ability of Example 4-5 to suppress internal defects of the film is further improved at this annealing temperature;

[0070] 3. It can be seen from Examples 1 and 6 that when Example 6 introduces argon, hydrogen, and argon and oxygen separately, although the total amount of the three gases introduced is the same as that in Example 1, since the gases in Example 1 have been mixed in advance, the weights of argon, oxygen, and hydrogen are different, which causes the gas inside the sputtering chamber to be stepped. The introduction of a mixed gas of argon and oxygen and a mixed gas of argon and hydrogen separately allows the gases to be further mixed and flow spontaneously in the sputtering chamber, thereby preventing the problem of uneven distribution of oxidizing gas and reducing gas caused by the stepped distribution of gases;

[0071] 4. It can be seen from Example 1, Example 6 and Comparative Example 1 and Comparative Example 2 that the same annealing temperature and annealing time are used:

[0072] The resistivity of Example 6 is reduced by 4.73×10 -4 Ω / cm 3 ;

[0073] The resistivity of Example 1 is reduced by 4.19×10 -4 Ω / cm 3 ;

[0074] It can be seen that when argon, hydrogen, and argon and oxygen are introduced separately during the sputtering process, the annealing operation improves the electrical capacity of the film more significantly.

[0075] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention shall be equivalent replacement methods and shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a TCO thin film, characterized in that: The following steps are involved: Step 1: depositing cerium indium oxide onto the surface of a glass substrate to obtain a glass substrate coated with cerium indium oxide; Step 2: annealing the glass substrate coated with indium cerium oxide in an environment of 100 to 500° C. for 5 to 30 minutes to obtain a TCO film.

2. The method for preparing a TCO thin film according to claim 1, characterized in that: The step 2 specifically includes: placing the glass substrate coated with cerium indium oxide in an environment of 200 to 300° C. and annealing for 5 to 30 minutes to obtain a TCO film.

3. The method for preparing a TCO thin film according to claim 1, characterized in that: The step 1 includes the following sub-steps: Step A1: cleaning the glass substrate, and then placing the cleaned glass substrate and the indium cerium oxide target into a preset position of the sputtering chamber; Step A2: Adjust the vacuum degree of the sputtering chamber to 5.2×10 -6 ~7.7×10 -6 torr, and then a mixed gas of argon, oxygen and hydrogen was introduced into the sputtering chamber and the vacuum degree of the sputtering chamber was adjusted to 2.5×10 -3 ~5.2×10 -3 torr; Step A3: sputtering and depositing the indium cerium oxide in the indium cerium oxide target onto the surface of the glass substrate to obtain a glass substrate coated with indium cerium oxide.

4. The method for preparing a TCO thin film according to claim 3, characterized in that: The mixed gas includes a mixed gas 1 of argon and oxygen and a mixed gas 2 of argon and hydrogen, and the flow ratio of the mixed gas 1 to the mixed gas 2 is 10-20:80-90; In the mixed gas 1, the mass ratio of argon to oxygen is 90-99:1-10; In the mixed gas 2, the mass ratio of argon to hydrogen is 90-99:1-10.

5. The method for preparing a TCO thin film according to claim 3, characterized in that: In step A1, the distance between the glass substrate and the indium cerium oxide target is 45 mm to 100 mm.

6. The method for preparing a TCO thin film according to claim 3, characterized in that: The step A3 is specifically as follows: sputtering and depositing the indium cerium oxide in the indium cerium oxide target onto the surface of the glass substrate at a sputtering power of 810 to 1430 W for a sputtering time of 5 to 10 minutes to obtain a glass substrate coated with indium cerium oxide.

7. A TCO film, characterized in that: The TCO film is prepared by the method for preparing the TCO film according to any one of claims 1 to 6.