Effect of hafnium addition on Zn-Sn-O thin film transistors fabricated by solution process

Abstract

The feasibility of controlling the threshold voltage (Vth) and field effect mobility (μFE) has been studied by adjusting hafnium ratio. Hafnium zinc tin oxide (HZTO) thin films were fabricated with various hafnium ratios. Vth shifted toward positive direction, and the μFE was decreased due to the decrease of carrier concentration, because hafnium acts as carrier suppressor. The subthreshold swing exhibits good properties from 1.01 to 0.44. The decrease of carrier concentration in HZTO is closely related with the decrease of the number of oxygen by hafnium ion.