The Preparation and Study of Al-doped Zinc Oxide (azo) Thin Film
|School||Huazhong University of Science and Technology|
|Keywords||AZO thin films Magnetron sputtering Sputtering parameters Optical and electrical properties|
Al-doped ZnO (AZO) thin film as a new kind of semiconductor optoelectronic materials, not only with high conductivity, high transmittance in the visible range, and abundant, inexpensive, good stability in hydrogen plasma, is now become the material of choice to replace ITO films. This article using laboratory-made ultra-high density AZO ceramic target AZO thin films using RF magnetron sputtering, XRD, SEM, four-probe tester, UV - visible spectrophotometer to characterize the performance of the film and analysis, to study the impact of different process parameters on film structure, morphology, electrical and optical properties, and exploratory development of AZO / ZnO, ITO / AZO composite film. The main conclusions are as follows: XRD and SEM analysis showed that all AZO films have a preferred orientation of the C-axis direction. With the increase in the temperature of the film substrate, the crystallization properties of the film becomes good, but when higher than 450 ° C, due to the high temperature close to the melting point of the glass causes the crystal film deteriorates. The sputtering power increases help to improve the crystalline properties of the film. Preferential growth of (002) plane of the film in a low oxygen-argon ratio of (0.1%), the performance of thin-film crystal deteriorates, but the higher the oxygen-argon ratio conducive film. The resistivity of the film is reduced as the substrate temperature increases to a temperature greater than 450 ° C, the resistivity increases. With the increase of the sputtering time, the resistivity of the film is reduced, which is due to the increase in film thickness, grain size, grain boundary scattering reduces mobility. The resistivity of the film decreases with increasing sputtering power, this is due to the increase of power can increase the carrier concentration and mobility. With the increase in the target-substrate distance, the increase in the resistivity of the film, this is because the increase of the target-substrate distance to reduce the sputter ion collision with other particles, thereby reducing the sputtering yield and the particle energy; However, target-substrate distance is too small It will increase the resistivity of the film. Resistivity first decreased and then increased with increasing gas pressure in 0.3Pa has the lowest resistivity. With the increase in the partial pressure of oxygen, the resistivity of the film increases. Transmittance of the films first increase and then decrease with increasing temperature, the transmittance of up to 84.47% at 400 ℃. Sputtering time increase will lead to a decline in transmittance of the film at 200 ° C substrate temperature the AZO film shortwave absorption limit the increase of the sputtering time is moved to the longer wavelength direction. With the increase in power, the transmittance of the film is reduced. With the increase in the target-substrate distance, the transmittance of the film is an increasing trend. The transmittance of the films showed decreased after increasing trend as the sputtering pressure, oxygen, argon ratio increases. ZnO buffer layer added help to improve the performance of the crystallization of AZO film with AZO film crystalline properties of ZnO film thickness increases better. Increasing the thickness of the ZnO buffer layer is beneficial to improve the conductivity of the film and the transmittance. ITO / AZO composite film having a good electrical conductivity, With the increase in the time of the AZO film sputtering ITO / AZO the resistivity of the composite film decreases, the transmittance decreased, the minimum value of the resistivity of the obtained composite film up to 1.27 × 10 -4 sup> Ω · cm.