Effects of wet etchant on the Al-doped In-Sn-Zn-O thin-film transistors with Cu/Cu diffusion barrier source-drain

Abstract

The purpose of this research is to create a thin-film-transistor of a back-channel-etched structure with low resistance Cu and high mobility A-ITZO. To suppress the diffusion characteristics of Cu, Mo-based alloys such as Mo-Al, Mo-Al-Ti, Mo-Ti were applied as a diffusion barrier. The problems of back-channel-etched structure, etching residue and damage of channel surface after etched by the conventional and F-free etchant, were compared. Later, each barrier and etchant was applied to the TFTs and identified the electrical characteristics. In the case of Mo-Ti, no residue was present for both etchant, but channel surface damage was decreased. For Mo-Al and Mo-Al-Ti S/D, the residual and channel surface damage were reduced. The electrical characteristics of the device that etched by F-free etchant have been improved. This research provide direction for the manufacture and design of TFTs applied with Cu.