Beneficial Hydrogen Doping in Single Spinel Phase Crystallized IZTO Thin-Film Transistors

Abstract

This study demonstrates different hydrogen (H) behavior in InZnSnO (IZTO) semiconductor depending on its crystalline structure. H-doped single spinel phase-IZTO (c-IZTO) thin-film transistors (TFTs) show exceptional device performances, with field-effect mobility of 114.8 ± 9.4 cm2/Vs, threshold voltage (<italic>V</italic>TH) of 0.2 ± 0.1 V, and subthreshold swing of 122 ± 20 mV/dec. Moreover, remarkable reliability with <italic>V</italic>TH shift (Δ<italic>V</italic>TH) < 0.1 V against external harsh bias temperature stresses is revealed in the c-IZTO TFTs, which is quite different from H-doped amorphous IZTO (a-IZTO) TFTs showing significant <italic>V</italic>TH shift of +2.2 (−3.5) V under positive (negative) bias temperature stress. This considerably higher reliability in the c-IZTO TFTs could be attributed to inhibited local transition of substitutional H by crystallization, unlike the a-IZTO TFTs, which were supported by density functional theory calculations.