Gate-All-Around Single-Crystal-Like Poly-Si Nanowire TFTs With a Steep-Subthreshold Slope

摘要

We investigate the characteristics of single-crystal-like (SCL) poly-Si nanowire (SCL poly-Si NW) thin-film-transistors with gate-all-around (GAA) structures. The GAA SCL poly-Si NWs are prepared by a modified sidewall spacer process utilizing an amorphous silicon ( $alpha$-Si) mesa structure. The combination of the high surface-to-volume ratio of the NW and a nominal gate length of 0.25 $mu{rm m}$ lead to clear improvement in electrical performance, including a steep subthreshold swing $(90pm 15~{rm mV}/{rm dec})$, a virtual absence of drain-induced barrier lowering $(21pm 13~{rm mV/V})$, and a very high ON/OFF current ratio ${sim}{7}times 10^{7}~(V_{rm D}=1~{rm V},~{rm V}_{rm G}=3~{rm V})$.