Fabrication of Oxide TFTs with Al[sub 2]O[sub 3]/ZnO Gate Stacks Patterned Using a Dry Etching Method

Abstract

In this paper, we describe a newly developed dry etching process for the fabrication of ZnO-based oxide thin-film transistors (TFTs). The dry etching behavior of ZnO and Al 2 O 3 thin films was systematically investigated by varying the etching gas mixtures and their mixing ratios in a dry etching system using high-density helicon plasma. We fabricated an oxide TFT using an Al 2 O 3 /ZnO gate stack patterned by dry etching and confirmed good device characteristics, in which the field effect mobility and the ratio of on/off drain currents were about 0.8 cm 2 /(V s) and 10 7 , respectively.