Enhanced crystallization and improved reliability for low-temperature-processed poly-Si TFTs with NH3-plasma pretreatment before crystallization

NH₃-plasma pretreatment before crystallization was performed for the first time on low-temperature-processed poly-Si thin-film transistors (TFTs). TFTs after pretreatment can significantly reduce the thermal crystallization time of amorphous silicon from 24 to 4 h. The pretreatment can also improve device performance and hot-carrier resistivity. It was attributed to the defect-state passivation of nitrogen that is piled-up near the poly-Si film surface, which helps to terminate the dangling bonds in poly-Si thin film in place of weaker Si-H and/or Si-Si bonds. This new scheme provides a simple and effective method to decrease α-Si film crystallization time and simultaneously improve device performance and reliability.