绝缘层材料及结构对薄膜晶体管性能的影响

Effect of insulating layer material and structure on performance of thin film transistors

基于半导体仿真软件Silvaco TCAD对薄膜晶体管(TFT)进行器件仿真,并结合实验验证,重点分析不同绝缘层材料及结构对TFT器件性能的影响。仿真及实验所用薄膜晶体管为底栅电极结构,沟道层采用非晶IGZO材料,绝缘层采用SiN_x和HfO_2多种不同组合的叠层结构。仿真及实验结果表明:含有高k材料的栅绝缘层叠层结构较单一SiN_x绝缘层结构的TFT性能更优;对SiN_x/HfO_2/SiN_x栅绝缘层叠层结构TFT,HfO_2取40nm较为合适;对含有高k材料的3层和5层绝缘层叠层结构TFT,各叠层厚度相同的对称结构TFT性能最优。本文通过仿真获得了TFT性能较优的器件结构参数,对实际制备TFT器件具有指导作用。

The paper focuses on analyzing the performance of thin film transistors with different insu- lation material and different insulation layer structures, based on semiconductor simulation software Silvaco TCAD and combined with experimental validation. The research model is based on the bottom grid structure, and the semiconductor layer is made of amorphous IGZO material. The insulation layer is made of different combinations of SiNe and HfO2 with overlapping structure. The simulation and ex- periment results show that the performance of transistors with high-k overlapping insulation layer structure is better than transistors with single SiN~ layer. For SiNx/HfO2/SiN~ structure, 40 nm thickness HfO2 is more appropriate. For transistors with 3 or 5 insulation layers containing high-k ma- terials, the symmetric structure with the same thickness for each layer is the best. The device struc- ture parameters of TFT obtained by simulation can guide the actual production of TFT devices.