Improving Negative-Bias-Temperature-Stress Stability for Thin-Film Transistors by Doping Mg Into ScInO Semiconductor

Abstract

Thin-film transistors (TFTs) with ScInO or MgScInO semiconductors were fabricated with the annealing temperature of only 150 °C. Compared with ScInO TFT, MgScInO TFT exhibited much better stability under negative-bias temperature stress (NBTS) at 60 °C with negative turn-on voltage ( ${V}_{ \mathrm{\scriptscriptstyle ON}}$ ) shift of −0.6 V at the initial stress stage (≤;900 s) and then positive $V_{ \mathrm{\scriptscriptstyle ON}}$ shift (>900 s). First-principles calculations show that the oxygen vacancies ( ${V}_{\text {O}}$ ) tend to be bounded with Mg and form Mg– ${V}_{\text {O}}$ pairs with activating (or binding) energy of greater than 0.1369 eV, which is ascribed to the NBTS stability improvement for MgScInO TFT.