Dependences of Structural Parameters on the Characteristics of Poly-Si Thin-Film Transistors after Plasma Passivation

The effects of NH₃ and H₂ plasma passivation on the characteristics of poly-Si thin-film transistors with source/drain extensions induced by a bottom sub-gate were studied. Our results show that significant improvements in device performance can be obtained by both passivation methods. Moreover, NH₃-plasma-treatment appears to be more effective in reducing the off-state leakage, subthreshold swing, compared to H₂ plasma passivation. NH₃ plasma treatment is also found to be more effective in reducing the anomalous subthrehold hump phenomenon observed in non-plasma-treated short-channel devices. Detailed analysis suggests that all these improvements can be explained by the more effective passivation of the traps distributed in both the front and back sides of the channel by NH ₃ plasma treatment.