CN103031556B - A kind of deposition preparation of ZnO/Al/ZnO photoelectricity transparent conductive film - Google Patents

Abstract

The invention belongs to the field of transparent conductive materials, and in particular relates to a deposition preparation method of a ZnO/Al/ZnO photoelectric transparent conductive film. The method of the present invention is to clean the glass substrate and send it into the gas phase deposition reaction chamber, feed argon and oxygen carrying Zn(CH ₂ CH ₃ ) ₂ into the reaction chamber at the same time, deposit and prepare a 20-50nm thick ZnO thin film, and then deposit The substrate is placed in a magnetron sputtering chamber, and pure Al is used as a target for magnetron sputtering, and a 5-30nm thick Al film is sputtered, and then the substrate is transferred to a vapor deposition reaction chamber, and deposited again to prepare a 20-50nm thick film. The thick ZnO film is annealed at a high temperature of 100-400 DEG C to obtain a photoelectric transparent conductive film with a structure of ZnO/Al/ZnO. The preparation process of the invention is simple, and the deposition process is easy to control. The transparent conductive film prepared by the invention has good uniformity and excellent photoelectric performance, and can be used for manufacturing transparent electrodes of photoelectric devices such as solar cells, light-emitting diodes, LCDs and mobile phones.

Description

A kind of deposition preparation method of ZnO/Al/ZnO photoelectric transparent conductive thin film

technical field

The invention belongs to the field of transparent conductive materials, and in particular relates to a deposition preparation method of a ZnO/Al/ZnO photoelectric transparent conductive film.

Background technique

With the development of society and the rapid advancement of science and technology, the demand for functional materials is increasing, and new functional materials have become the key to the development of new technologies and emerging industries. With the development of industries such as solar energy, flat panel display and semiconductor lighting, a new functional material - transparent conductive material has been produced and developed. General conductive materials such as metals and alloy-based semiconductors are opaque materials, but in practical applications, such as solar cell electrodes, thin film solar cell electrodes, liquid crystal display electrodes, etc., are required to be able to transmit visible light while conducting electricity Generally speaking, a transparent conductive material can be made by meeting the following two requirements: (1) The average transmittance T _avg of visible light (wavelength λ=380-780nm) >80%; (2) Excellent electrical conductivity, The resistivity is lower than 10 ^-3 Ω·cm.

The currently developed transparent conductive semiconductors are all wide bandgap oxide semiconductor materials, that is, transparent conductive oxide (TCO film for short), which have a wide band gap, high light transmittance in the visible spectrum region, and low resistivity. The common photoelectric properties, after appropriate doping, can further improve its electrical conductivity, which has broad application prospects.

At present, there are mainly three types of TCO materials widely used, ITO-In ₂ O ₃ based thin film (Sn doped), FTO-SnO ₂ based thin film (F doped) and AZO-ZnO based thin film (Al doped), respectively. The introduction is as follows: (1) The crystal structure of ITO-In ₂ O ₃ is a body-centered cubic ferromanganese structure, and the band gap is about 3.5eV, so it is transparent in the visible light range, T _avg >90%, and the lowest resistivity can reach 10 ^-5 Ω ^. cm magnitude. ITO is currently the most mature and widely used TCO. However, because ITO must use the rare metal indium (China's indium reserves are 13,000 tons, accounting for about 2/3 of the world), resulting in high production costs. With the TFT-LCD panel With the continuous expansion of the market and the further development of solar cells, 83% of the global indium consumption is used for ITO, which also leads to the problem that indium mines will gradually be exhausted in the future, and the indium material is toxic and harmful to the human body during preparation and application. harmful. In addition, the atomic weight of indium and tin is relatively large, and it is easy to penetrate into the substrate during the film formation process, poisoning the substrate material, especially in liquid crystal display devices. For the solar industry, TCO glass must have the ability to improve light scattering. , and ITO coating is difficult to do this, and the laser etching performance is poor, and ITO is not stable enough in the plasma. In short, it is imperative to find suitable alternative products; (2) FTO-SnO ₂ has positive four The rutile structure of the body has a band gap of 3.6eV. The FTO film obtained by doping fluorine can further enhance the conductivity. Compared with ITO, FTO has the advantages of high thermal stability, corrosion resistance, and high hardness. It has good stability, so it has become a photovoltaic TCO material for commercial application at present. However, it is difficult to prepare high-quality crystalline FTO thin films, and the requirements for the preparation process are high. Due to the existence of internal defects in the thin film, the light transmittance and electrical conductivity It is lower than the ITO film, and at the same time, there is a certain pollution in the process due to the need for fluorine element (very toxic) doping. In addition, due to the high hardness of the FTO film, it is more difficult to etch; (3) AZO-ZnO belongs to the N-type II-VI group Semiconductor material, its crystal structure is hexagonal wurtzite structure, the bandgap width is about 3.4eV, and the light transmittance can reach more than 90%. At the same time, ZnO also has a high Conductivity, the conductivity can be further improved by doping with group III elements (Al, Ga, B). ZnO used in TCO thin films has significant advantages such as abundant raw materials, low cost, simple preparation process, non-toxic, and non-polluting environment. , ZnO can be more stable than ITO film in hydrogen plasma, has photoelectric properties comparable to ITO film and is easy to etch. In addition, ZnO can efficiently transmit short-wavelength light that ITO is difficult to transmit, so whether it is in In solar cells or flat panel displays, ZnO is a strong competitor to replace ITO and FTO.

At present, there are many related reports on ZnO and ZnO-doped Al-doped thin films. However, with the general doping method, the penetration effect of Al elements in the vacancy defects of ZnO is not good, and the carrier concentration is not high. The contribution of electrical conductivity is very limited. Therefore, how to better dope Al elements into ZnO thin films and further improve the electrical conductivity of conductive transparent materials is an urgent problem to be solved.

Contents of the invention

The present invention aims at the problems existing in the prior art, and the present invention provides a method for depositing and preparing ZnO/Al/ZnO photoelectric transparent conductive film. The ZnO/Al/ZnO transparent conductive film with excellent quality and good electrical conductivity can be deposited by combining methods. Its resistivity can be as low as 9.2×10 ^-5 Ω·cm, and its light transmittance can reach more than 80%.

The technical scheme that realizes the object of the present invention carries out according to the following steps:

(1) After the glass substrate was ultrasonically cleaned with acetone, ethanol and deionized water in sequence, it was blown dry with nitrogen and sent to the vapor deposition reaction chamber. After the reaction chamber was evacuated to 7.0×10 ^-4 Pa, the substrate was heated to 400°C, simultaneously feed argon and oxygen carrying Zn(CH ₂ CH ₃ ) ₂ into the reaction chamber, wherein the flow ratio of argon and oxygen is 1: (100-150), control the microwave power to 650W, and deposit and prepare 20-50nm thick ZnO thin film, after the deposition is completed, the vapor deposition reaction chamber is cleaned with high-purity nitrogen gas, and the substrate is taken out;

(2) Place the substrate deposited with ZnO film in the magnetron sputtering chamber, vacuum the magnetron sputtering chamber to 10 ^-4 Pa, heat the substrate to 100°C, and control the air pressure to 8Pa by introducing argon gas , using pure Al as the target for magnetron sputtering, the sputtering power is 100W, the sputtering time is 1-5min, and a 5-30nm thick Al film is sputtered on a glass substrate deposited with a ZnO film;

(3) Transfer the sputtered substrate to the vapor deposition reaction chamber, vacuumize the reaction chamber to 7.0×10 ^-4 Pa, heat the substrate to 400°C, and introduce Zn (CH ₂ CH ₃ ) ₂ argon and oxygen, where the flow ratio of argon and oxygen is 1: (100-150), control the microwave power to 650W, and deposit again to prepare a 20-50nm thick ZnO film, after the deposition Clean the vapor deposition reaction with high-purity nitrogen, and take out the substrate;

(4) Annealing the above substrate at a high temperature of 100-400° C. for 30 minutes to obtain a photoelectric transparent conductive film with a structure of ZnO/Al/ZnO.

The glass substrate is a common Corning glass substrate.

Compared with the prior art, the characteristics and beneficial effects of the present invention are:

The method of the present invention adopts the combination of plasma-enhanced electron cyclotron resonance organic chemical vapor deposition technology and magnetron sputtering technology, and utilizes the good photoelectric properties of ZnO and the low resistivity of Al to form a composite thin film of ZnO/Al/ZnO structure , and then subjected to high temperature annealing treatment;

The sandwich structure of ZnO/Al/ZnO is very conducive to the diffusion and penetration of Al between the films. Due to the doping of Al, the carrier concentration in the holes of ZnO increases, and the conductivity of the film is greatly improved. At the same time, The light transmittance can be kept above 80%. Because it is organic chemical vapor deposition, the film quality is excellent;

The preparation process of the invention is simple, and the deposition process is easy to control. The transparent conductive film prepared by the invention has good uniformity and excellent photoelectric performance, and can be used for manufacturing transparent electrodes of photoelectric devices such as solar cells, light-emitting diodes, LCDs and mobile phones.

Description of drawings

Fig. 1 is the ZnO/Al/ZnO transparent conductive film schematic diagram that the inventive method obtains;

Among them: 1: glass substrate; 2: ZnO film; 3: Al interlayer film;

Fig. 2 is the light transmittance diagram of the ZnO/Al/ZnO transparent conductive film prepared in Example 1 of the present invention under the wavelength of visible light;

3 is an SEM image of the ZnO/Al/ZnO transparent conductive film prepared in Example 1 of the present invention.

Detailed ways

The plasma-enhanced electron cyclotron resonance organic chemical vapor deposition system described in the present invention, that is, the ECR-PEMOCVP system, has been disclosed in the patent application with the application number 201210247144.8; the described magnetron sputtering control system is JPGD-450 magnetron sputtering shooting platform.

The present invention will be further described below in conjunction with embodiment.

Example 1

After the glass substrate is ultrasonically cleaned with acetone, ethanol and deionized water in sequence, it is blown dry with nitrogen and sent to the vapor deposition reaction chamber;

After the reaction chamber was evacuated to 7.0×10 ^-4 Pa, the substrate was heated to 400°C, and argon and oxygen carrying Zn(CH ₂ CH ₃ ) ₂ were introduced into the reaction chamber at the same time, wherein the argon and oxygen The flow ratio is 1: 150, the microwave power is controlled at 650W, and a 20nm thick ZnO film is deposited and prepared. After the deposition, the vapor deposition reaction chamber is cleaned with high-purity nitrogen gas, and the substrate is taken out;

Place the substrate deposited with ZnO thin film in the magnetron sputtering chamber, vacuumize the magnetron sputtering chamber to 10 ^-4 Pa, heat the substrate to 100°C, pass in argon gas to control the pressure at 8Pa, and use pure Al Carry out magnetron sputtering for the target material, the sputtering power is 100W, and the sputtering time is 1min, and a 5nm thick Al film is sputtered on the glass substrate deposited with the ZnO film;

Transfer the sputtered substrate to the vapor deposition reaction chamber, vacuumize the reaction chamber to 7.0×10 ^-4 Pa, heat the substrate to 400°C, and introduce Zn(CH ₂ CH ₃ ) ₂ of argon and oxygen, wherein the flow ratio of argon and oxygen is 1:100, control the microwave power to 650W, and deposit again to prepare a 20nm thick ZnO film. After the deposition, use high-purity nitrogen to clean the vapor deposition reaction. Take out the substrate;

The above substrate is annealed at a high temperature of 100 DEG C to obtain a photoelectric transparent conductive film with a structure of ZnO/Al/ZnO.

Its light transmittance in the visible light range was tested, as shown in Figure 2, it can be seen that its light transmittance is above 80%, and its SEM image is shown in Figure 3, from which it can be seen that Al particles and The uniform doping of ZnO particles is beneficial to enhance its electrical properties.

Example 2

After the glass substrate is ultrasonically cleaned with acetone, ethanol and deionized water in sequence, it is blown dry with nitrogen and sent to the vapor deposition reaction chamber;

After the reaction chamber was evacuated to 7.0×10 ^-4 Pa, the substrate was heated to 400°C, and argon and oxygen carrying Zn(CH ₂ CH ₃ ) ₂ were introduced into the reaction chamber at the same time, wherein the argon and oxygen The flow ratio is 1: 100, the microwave power is controlled to 650W, and a 30nm thick ZnO film is deposited and prepared. After the deposition, the vapor deposition reaction chamber is cleaned with high-purity nitrogen gas, and the substrate is taken out;

Place the substrate deposited with ZnO thin film in the magnetron sputtering chamber, vacuumize the magnetron sputtering chamber to 10 ^-4 Pa, heat the substrate to 100°C, pass in argon gas to control the pressure at 8Pa, and use pure Al Carry out magnetron sputtering for the target material, the sputtering power is 100W, the sputtering time is 2min, and a 10nm thick Al film is sputtered on the glass substrate deposited with the ZnO film;

Transfer the sputtered substrate to the vapor deposition reaction chamber, vacuumize the reaction chamber to 7.0×10 ^-4 Pa, heat the substrate to 400°C, and introduce Zn(CH ₂ CH ₃ ) ₂ of argon and oxygen, wherein the flow ratio of argon and oxygen is 1:110, control the microwave power to 650W, and deposit again to prepare a 30nm thick ZnO film. After the deposition, use high-purity nitrogen to clean the vapor deposition reaction. Take out the substrate;

The above substrate is annealed at a high temperature of 200 DEG C to obtain a photoelectric transparent conductive film with a structure of ZnO/Al/ZnO.

Example 3

After the glass substrate is ultrasonically cleaned with acetone, ethanol and deionized water in sequence, it is blown dry with nitrogen and sent to the vapor deposition reaction chamber;

After the reaction chamber was evacuated to 7.0×10 ^-4 Pa, the substrate was heated to 400°C, and argon and oxygen carrying Zn(CH ₂ CH ₃ ) ₂ were introduced into the reaction chamber at the same time, wherein the argon and oxygen The flow ratio is 1: 120, the microwave power is controlled at 60W, and a 40nm thick ZnO film is deposited and prepared. After the deposition, the vapor deposition reaction chamber is cleaned with high-purity nitrogen gas, and the substrate is taken out;

Place the substrate deposited with ZnO thin film in the magnetron sputtering chamber, vacuumize the magnetron sputtering chamber to 10 ^-4 Pa, heat the substrate to 100°C, pass in argon gas to control the pressure at 8Pa, and use pure Al Carry out magnetron sputtering for the target material, the sputtering power is 100W, the sputtering time is 3min, and a 20nm thick Al film is sputtered on the glass substrate deposited with the ZnO film;

Transfer the sputtered substrate to the vapor deposition reaction chamber, vacuumize the reaction chamber to 7.0×10 ^-4 Pa, heat the substrate to 400°C, and introduce Zn(CH ₂ CH ₃ ) ₂ argon and oxygen, wherein the flow ratio of argon and oxygen is 1:140, control the microwave power to 650W, and deposit again to prepare a 40nm thick ZnO film. After the deposition, the vapor deposition reaction is cleaned with high-purity nitrogen. Take out the substrate;

The above-mentioned substrate is annealed at a high temperature of 300° C. for 30 minutes to obtain a photoelectric transparent conductive film with a structure of ZnO/Al/ZnO.

Example 4

After the glass substrate is ultrasonically cleaned with acetone, ethanol and deionized water in sequence, it is blown dry with nitrogen and sent to the vapor deposition reaction chamber;

After the reaction chamber was evacuated to 7.0×10 ^-4 Pa, the substrate was heated to 400°C, and argon and oxygen carrying Zn(CH ₂ CH ₃ ) ₂ were introduced into the reaction chamber at the same time, wherein the argon and oxygen The flow ratio is 1:120, the microwave power is controlled to 650W, and a 50nm thick ZnO film is deposited and prepared. After the deposition, the vapor deposition reaction chamber is cleaned with high-purity nitrogen gas, and the substrate is taken out;

Place the substrate deposited with ZnO thin film in the magnetron sputtering chamber, vacuumize the magnetron sputtering chamber to 10 ^-4 Pa, heat the substrate to 100°C, pass in argon gas to control the pressure at 8Pa, and use pure Al Carry out magnetron sputtering for the target material, the sputtering power is 100W, and the sputtering time is 4min, and a 30nm thick Al film is sputtered on the glass substrate deposited with the ZnO film;

Transfer the sputtered substrate to the vapor deposition reaction chamber, vacuumize the reaction chamber to 7.0×10 ^-4 Pa, heat the substrate to 400°C, and introduce Zn(CH ₂ CH ₃ ) ₂ of argon and oxygen, wherein the flow ratio of argon and oxygen is 1:150, control the microwave power to 650W, and deposit again to prepare a 50nm thick ZnO film, and clean the vapor deposition reaction with high-purity nitrogen after the deposition. Take out the substrate;

The above-mentioned substrate is annealed at a high temperature of 400° C. for 30 minutes to obtain a photoelectric transparent conductive film with a structure of ZnO/Al/ZnO.

Example 5

After the glass substrate is ultrasonically cleaned with acetone, ethanol and deionized water in sequence, it is blown dry with nitrogen and sent to the vapor deposition reaction chamber;

After the reaction chamber was evacuated to 7.0×10 ^-4 Pa, the substrate was heated to 400°C, and argon and oxygen carrying Zn(CH ₂ CH ₃ ) ₂ were introduced into the reaction chamber at the same time, wherein the argon and oxygen The flow ratio is 1: 150, the microwave power is controlled at 650W, and a 20nm thick ZnO film is deposited and prepared. After the deposition, the vapor deposition reaction chamber is cleaned with high-purity nitrogen gas, and the substrate is taken out;

Place the substrate deposited with ZnO thin film in the magnetron sputtering chamber, vacuumize the magnetron sputtering chamber to 10 ^-4 Pa, heat the substrate to 100°C, pass in argon gas to control the pressure at 8Pa, and use pure Al Carry out magnetron sputtering for the target material, the sputtering power is 100W, and the sputtering time is 5min, and a 20nm thick Al film is sputtered on a glass substrate with a ZnO thin film;

Transfer the sputtered substrate to the vapor deposition reaction chamber, vacuumize the reaction chamber to 7.0×10 ^-4 Pa, heat the substrate to 400°C, and introduce Zn(CH ₂ CH ₃ ) ₂ of argon and oxygen, wherein the flow ratio of argon and oxygen is 1:120, and the microwave power is controlled to 650W, and a 30nm thick ZnO film is deposited again, and the vapor deposition reaction is cleaned with high-purity nitrogen after the deposition. Take out the substrate;

The above substrate is annealed at a high temperature of 250° C. for 30 minutes to obtain a photoelectric transparent conductive film with a structure of ZnO/Al/ZnO.

Claims (1)

1. a deposition preparation method of ZnO/Al/ZnO photoelectric transparent conductive film, carry out according to the following steps: (1) After the glass substrate is ultrasonically cleaned with acetone, ethanol and deionized water in sequence, it is blown dry with nitrogen and sent to the vapor deposition reaction chamber. After the reaction chamber is evacuated to 7.0×10 ^-4 Pa, it is characterized in that: Heat the substrate to 400°C, feed argon and oxygen carrying Zn(CH ₂ CH ₃ ) ₂ into the reaction chamber at the same time, wherein the flow ratio of argon and oxygen is 1:(100-150), and control the microwave power For 650W, deposit and prepare a 20-50nm thick ZnO film. After the deposition is completed, the vapor deposition reaction chamber is cleaned with high-purity nitrogen gas, and the substrate is taken out; (2) Place the substrate deposited with the ZnO film in the magnetron sputtering chamber, vacuum the magnetron sputtering chamber to 10 ^-4 Pa, heat the substrate to 100°C, and control the air pressure to 8Pa by introducing argon gas , using pure Al as the target for magnetron sputtering, the sputtering power is 100W, the sputtering time is 1-5min, and a 5-30nm thick Al film is sputtered on a glass substrate deposited with a ZnO film; (3) Transfer the sputtered substrate to the vapor deposition reaction chamber, vacuumize the reaction chamber to 7.0×10 ^-4 Pa, heat the substrate to 400°C, and simultaneously introduce Zn (CH ₂ CH ₃ ) ₂ argon and oxygen, wherein the flow ratio of argon and oxygen is 1: (100-150), control the microwave power to 650W, and deposit again to prepare a 20-50nm thick ZnO film, after the deposition Clean the vapor deposition reaction with high-purity nitrogen, and take out the substrate; (4) Annealing the above substrate at a high temperature of 100-400° C. for 30 minutes to obtain a photoelectric transparent conductive film with a structure of ZnO/Al/ZnO, and the light transmittance of the film in the visible light range is above 80%.