Effects of plasma treatments on the characteristics of poly-Si thin-film transistors having electrical junctions induced by a bottom sub-gate

Abstract

The effects of H-2 and NH3 plasma on poly-Si thin-film transistors with source/drain extensions induced by a bottom sub-gate were investigated. Significant improvement in device characteristics could be made using the two methods, though the NH3-plasma-treated devices show better performance than the H-2-plasma-treated counterparts in terms of lower off-state leakage, smaller subthreshold swing, and improved mobility, etc. Moreover, an anomalous subthreshold hump phenomenon observed in short-channel devices is also less significant for the devices treated by NH3 plasma. Our analysis indicates that the NH3 plasma is more effective in passivating the traps distributing in both front and back sides of the channel.