Simulation of the influence of the gate dielectric on amorphous indium-gallium-zinc oxide thin-film transistor reliability

摘要

Indium-gallium-zinc oxide (IGZO) thin films have attracted significant attention for application in thin-film transistors (TFTs) due to their specific characteristics, such as high mobility and transparency. The performance of a-IGZO TFTs with four different insulators (SiO2 Si3N4, Al2O3 and HfO2) is examined using a numerical simulator (Silvaco Atlas). It is found that the output performance is significantly enhanced with high relative permittivity of the insulator. HfO2 gives the best performance: lower threshold voltage 0.23V and subthreshold 0.09Vdec(-1), higher field-effect mobility 13.73cm(2)s(-1)V(-1) and on current (I-on) and I-on/I-off ratio 2.81x10-6 A, 5.06x1012, respectively. Therefore, HfO2 gate showed high stability compared with other gate insulator materials.