Comparative studies of ZnON and ZnO thin film transistors fabricated by DC reactive sputtering method

Abstract

DC reactive sputtered ZnO and ZnON thin film transistors (TFTs) was fabricated in order to investigate the role of nitrogen element in the ZnO matrix. After low vacuum annealing at 25 °C, ZnON TFTs exhibited superior device performances (Vth = -0.16V, μsat, = 40.87cm2/Vs and SS = 77V/decade),comparing with ZnO TFT's performance (Vlh = 3.28V, μsat = 0.99 cm2/Vs and SS = 1.22 V/decade) under vacuum probe condition (10-3 torr). The physical and electronic structure was analyzed by X-ray diffraction and X-ray absorption spectroscopy, respectively. The chemical bonding status was also analyzed by X-ray photoelectron spectroscopy. Consequently, nitrogen incorporation in DC reactive spurring can suppress the crystal growth and enhance electron mobility due to Zn-N bonding.