Optimization of the Fabrication Process for ZnO Thin-Film Transistors with HfO2 Gate Dielectrics

[[abstract]]In this work, we address the analysis of ZnO thin films and electrical characteristics of ZnO thin film transistors (TFTs) with HfO2 high-k gate dielectrics after low-temperature postannealing. The SIMS analysis shows that the diffusion of Zn atoms into the HfO2 gate dielectrics will occur after 300 degrees C annealing and the related electrical characteristics indicate that 200 degrees C annealing will be the suitable annealing condition for ZnO/HfO2/ITO-based TFTs. The ZnO TFTs after 200 degrees C annealing exhibited transistor behavior over the range of 0-7V; the field effect mobility, subthreshold slope, and on/off ratio were measured to be 1.3 cm(2)V(-1)s(-1), 0.5 V/decade, and similar to 10(6), respectively. (C) 2009 The Japan Society of Applied Physics[[note]]SC