溅射气压对铟锡锌氧化物薄膜晶体管性能的影响

Fabrication and Characterization of In_2O_3-SnO_2-ZnO Thin Film Transistor

利用射频磁控溅射技术,在不同溅射气压下制备了铟锡锌氧化物薄膜晶体管(ITZO TFT),分析了ITZO TFT电学性能随气压的变化规律。研究结果表明:非晶ITZO TFT的工作模式均为耗尽型;随着气压的增大,亚阈值摆幅及阈值电压先减小后增大、场效应迁移率逐渐减小,这是由载流子浓度和界面缺陷密度两方面因素共同决定的。溅射气压为0.4 Pa时,ITZO TFT综合性能最好,场效应迁移率高达24.32 cm^2/V·s,亚阈值摆幅为1.10 V/decade,电流开关比达到10~6。此外,ITZO有源层在可见光范围内的平均透过率超过80%,光学带隙值在3.2~3.4 eV之间,随气压的升高先减小后增大。

The In_2O_3-SnO_2-ZnO thin film transistor（ITZO TFT） was fabricated by RF magnetron sputtering.The influence of the pressure on the electrical and optical properties of the ITZO TFTs was investigated.The results show that the pressure significantly affects the characteristics of the amorphous ITZO TFT working in depletion mode.For example,as the pressure increased,the sub-threshold swing and threshold voltages changed in a decreaseincrease way;and the field effect mobility slowly decreased,possibly because of dominance of the carriers concentration and interfacial defects density.Fabricated at 0.4 Pa,the ITZO TFT exhibits the optimized properties：a field effect mobility of 24.32 cm^2/V · s,a sub-threshold swing of 1.10 V/decade and an I_（on/off） ratio of 10~6.In addition,the average transmittance of ITZO active layer was over 80%in visible light range,and the optical band gap,in 3.2~3.4 eV range,varied in a decrease-increase manner with an increase of the pressure.