铋掺杂氧化铟锌薄膜晶体管的研究

Investigation of Bismuth Doped Indium-Zinc-Oxide Thin Film Transistors

采用射频磁控溅射法制备了以非晶铋掺杂氧化铟锌(a-IZBO)为沟道层的薄膜晶体管(TFTs).相比本征的氧化铟锌薄膜晶体管,a-IZBO-TFTs显示出更低的关态电流,正向偏移的开启电压,表明铋掺杂能有效抑制载流子浓度.在铋掺杂含量为原子百分比8.6%时达到最佳的电学性能:载流子迁移率为7.5cm^2/(V·s),开关比为3×10~8,亚阈值摆幅为0.41V/decade.使用光致发光激发谱和X射线光电子能谱评价了a-IZBO沟道层中的氧空位缺陷,分析结果证实了铋的掺杂确实有效地减少了氧空位,从而抑制了半导体沟道层中的载流子浓度,对a-IZO-TFTs的总体电学性能改善起到较大的作用.

Amorphous bismuth doped indium zinc oxide thin film transistors（a-IZBO-TFTs）were prepared by rf magnetron sputtering at room temperature.Compared with the intrinsic indium zinc oxide TFTs,a-IZBO-TFTs show lower off-current and positive turn-on voltage shift.The optimum a-IZBO-TFT performance in enhancement mode was obtained at Bi doping content of 8.6%,with the mobility of 7.5cm2/（V·s）,on/off current ratio of 3×10^8,and subthreshold swing of 0.41V/decade.PL spectra as well as XPS spectra were used to evaluate the oxygen vacancy defects in the a-IZBO channel layers.It is found that Bi doping is effective on suppressing the oxygen vacancies and thus the carrier concentration and improving the comprehensive electrical performance of IZO-TFT devices.