Positive Bias Stress Instability of In-Ga-Zn-O Thin-Film Transistors with Al2O3/TEOS Oxide Gate Dielectrics

Abstract

The Vth shift (Delta Vth) of a-IGZO devices with gate dielectrics of Al2O3 and TEOS oxide after at a gate bias of +20V for 3600 s are +3.66V and -2.18V, respectively. Moreover, the V-th shift of two stacked dielectrics Al2O3 /TEOS oxide by using the equivalent capacitance with 100-nm-thick TEOS oxide. Two stacked dielectrics with a 10-nm-thick Al2O3 and a 96-nm-thick TEOS oxide, Delta Vth decreases to -0.42V after a gate bias of +20 V for 6400 s.