沟道宽度对ZnO-TFT电学性能的影响

Effects of Channel Width on The Electrical Properties of ZnO-based Thin Film Transistor

用射频磁控溅射法生长的ZnO薄膜作为有源层,制备出了ZnO基薄膜晶体管(ZnO-TFT),并在空气环境下350℃退火1 h,研究了沟道宽度对ZnO-TFT器件性能的影响。实验结果表明:阈值电压随着沟道宽度的减小而增加,这是由于沟道越窄,载流子被捕获的几率越大,在相同栅压下沟道内可动载流子浓度越小,相应的阈值电压就越大;饱和迁移率随着沟道宽度的减小而增加,认为这是由源/漏电阻的侧壁效应及边缘电子场效应引起的附加电流所致。

ZnO-based thin film transistors(ZnO-TFTs) with RF-sputtered ZnO active layer were fabricated at room temperature,and then annealed at 350 ℃ for 1 h in the air environment.Effects of channel width on the electrical properties of ZnO-TFTs were investigated.The threshold voltage increases with the decrease of the channel width,that is because the more narrower the channel width is,the more greater probability of carriers is captured,the less free carriers are under the same gate voltage,so that the more greater the threshold voltage is.The saturation carrier mobility also increases with the decrease of the channel width,due to the side wall effect associated with source / drain resistance as well as the fringing electronic-field effects which led to an additional current flow beyond the device edges.