Analysis of Improved Performance Under Negative Bias Illumination Stress of Dual Gate Driving a-IGZO TFT by TCAD Simulation

We report the numerical simulation of the effect of a dual gate (DG) TFT structure operating under dual gate driving on improving negative bias illumination stress (NBIS) of amorphous indium gallium zinc oxide thin-film transistors (a-IGZO TFTs). With respect to the transfer characteristics of a-IGZO TFTs, we show a larger negative threshold voltage shift (ΔVTH) with increasing a-IGZO active layer thickness. This trend is confirmed by TCAD simulation, where the initial transfer curve is plotted under varying a-IGZO thickness keeping a constant density of states. Under varying a-IGZO thickness, TCAD simulation results confirm TFTs under DG driving shows significantly less ΔVTH shift under NBIS compared with that of single gate (SG) driving TFTs. Under 10 K seconds of NBIS, TCAD simulation results show the increase in donor-like states (NGD) by 5.25 × 10
¹⁷
cm
^-3
eV
^-1
and acceptor-like states (NGA) by 7.5 × 10
¹⁶
cm
^-3
eV
^-1
.