Self-passivated copper as a gate electrode in a poly-Si thin film transistor liquid crystal display

Self-passivated copper as a gate electrode in the form of TiO/Cu/TiO/TiN/Si O2 has been obtained by annealing Cu/Ti/TiN/SiO2. The thickness of Ti in Cu /TiTiN was optimized at 150 Angstrom by forming an 80 Angstrom continuous T iO film on the outer surface of the Cu. The multilayer of SiO2/TiO/Cu/TiO/T iN/SiO2 showed stable electrical passivating properties against Cu diffusio n into the top or bottom SiO2. Consequently, self-passivated copper has sec ured the dielectric properties of plasma enhanced chemical vapor deposition SiO2 and can be utilized as a gate electrode in low temperature poly-Si th in film transistor liquid crystal displays without sacrificing the low resi stivity of Cu. (C) 2001 American Institute of Physics.