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/SiO2 has been obtained by annealing Cu/Ti/TiN/SiO2. The thickness of Ti in Cu/TiTiN was optimized at 150 Å by forming an 80 Å continuous TiO film on the outer surface of the Cu. The multilayer of SiO2/TiO/Cu/TiO/TiN/SiO2 showed stable electrical passivating properties against Cu diffusion into the top or bottom SiO2. Consequently, self-passivated copper has secured the dielectric properties of plasma enhanced chemical vapor deposition SiO2 and can be utilized as a gate electrode in low temperature poly-Si thin film transistor liquid crystal displays without sacrificing the low resistivity of Cu.