非晶铟锌钨氧化物薄膜晶体管的电学性能和稳定性研究

Performance and Stability of Thin Film Transistors Made of Amorphous Indium Zinc Tungsten Oxides

采用射频磁控溅射法制备了非晶铟锌钨氧化物(a-IZWO)薄膜和以此半导体薄膜为沟道层的薄膜晶体管。研究了沟道宽长比和退火时间对器件电学性能的影响。结果表明,沟道宽长比为400μm:400μm的器件经过120min200℃空气退火后其电学性能达到最佳,场效应迁移率达到7.29 cm^2/Vs,阈值电压为-2.86 V,电流开关比超过10~7,亚阈值摆幅低至0.13 V/decade。偏压稳定性测试结果证实了器件的偏压稳定性主要受到沟道层缺陷、背沟道表面氧离子和H_2O^+离子吸附等因素的影响。随着器件沟道宽长比不断增大,退火时间不断延长,器件受到这些因素的影响变小,稳定性越来越好。

The thin film transistors（ TFTs）,with channel layer made of magnetron-sputtered amorphous indium zinc tungsten oxides（ a-IZWO）,were fabricated on substrate of n-type thermal oxidized Si. The influence of the annealing conditions and channel width/length ratio on the performance and stability of TFTs was investigated. The results show that the width/length ratio and annealing time has a major impact. To be specific,annealed at 200℃ for 120 min in air,the optimized properties of TFT with channel width/length ratio of 400 μm： 400 μm included： a field effect mobility of 7. 29 cm^2/Vs,a threshold voltage of -2. 86 V,a current on/off ratio over 10~7,and a subthreshold swing of 0. 13 V/decade. As the annealing time and width/length ratio increased,the intrinsic oxygen vacancy density in the channel layer and adsorbed O^（-2）/H_2O~＋ ions on the backchannel surfaces considerably decreased,resulting in an increasing enhancement of the gate bias stability.