Oxygen Vacancy Controlled SiZnSnO Thin‐Film Inverters with High Gain

Abstract

Amorphous SiZnSnO (a‐SZTO) thin films are successfully deposited to control the electrical characteristics by changing the oxygen partial pressure [p(O2)] ratio during the deposition. As the p(O2) ratio increases, the on current, off current, and the field effect mobility (μFE) decrease and the threshold voltage (Vth) shift to the positive direction gradually. This phenomenon occurs because the oxygen vacancies (VO) in the channel are suppressed due to the effect of oxygen injected during the deposition. To explore the possibility that the device can be applied to integrated thin‐film circuit and operate well in the application, the n‐type only inverters are fabricated using VO controlled thin‐film transistors (TFTs). All inverters have clear voltage transfer characteristics (VTCs) and well operate in the range of 3–15 V of VDD. When Vth shifts to positive direction in enhancement mode (E‐mode), the voltage transition region (Vtr) of the inverter also shifts to positive direction. The highest voltage gain is measured to be about 26.554 V/V at 15 V of VDD. It is proposed to be able to fabricate the inverters and control the transition value of VTCs of the inverter simply by changing p(O2) ratio of E‐mode TFT.