Effects of Oxynitride Buffer Layer on the Electrical Characteristics of Poly-Silicon TFTs Using $\hbox{Pr}_{2}\hbox{O}_{3}$ Gate Dielectric

In this paper, we have developed high-k Pr
₂
O
₃
poly-Si thin-film transistors (TFTs) using different N
₂
O plasma power treatments. High-k Pr
₂
O
₃
poly-Si TFT devices using a 200-W plasma power exhibited better electrical characteristics in terms of high effective carrier mobility, high driving current, small subthreshold slope, and high I
_ON
/I
_OFF
current ratio. This result is attributed to the smooth Pr
₂
O
₃
/poly-Si interface and low interface trap density. Pr
₂
O
₃
poly-Si TFT with a 200-W N
₂
O plasma power also enhanced electrical reliabilities such as hot carrier and positive bias temperature instability. All of these results suggest that a high-k Pr
₂
O
₃
gate dielectric with the oxynitride buffer layer is a good candidate for high-performance low-temperature poly-Si TFTs.