Temperature Effects on a‐IGZO Thin Film Transistors Using HfO2 Gate Dielectric Material

Abstract

This study investigated the temperature effect on amorphous indium gallium zinc oxide (a‐IGZO) thin film transistors (TFTs) using hafnium oxide (HfO2) gate dielectric material. HfO2 is an attractive candidate as a high‐κ dielectric material for gate oxide because it has great potential to exhibit superior electrical properties with a high drive current. In the process of integrating the gate dielectric and IGZO thin film, postannealing treatment is an essential process for completing the chemical reaction of the IGZO thin film and enhancing the gate oxide quality to adjust the electrical characteristics of the TFTs. However, the hafnium atom diffused the IGZO thin film, causing interface roughness because of the stability of the HfO2 dielectric thin film during high‐temperature annealing. In this study, the annealing temperature was optimized at 200°C for a HfO2 gate dielectric TFT exhibiting high mobility, a high ION/IOFF ratio, low IOFF current, and excellent subthreshold swing (SS).