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

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 $(90\pm 15~{\rm mV}/{\rm dec})$ , a virtual absence of drain-induced barrier lowering $(21\pm 13~{\rm mV/V})$ , and a very high ON/OFF current ratio ${\sim}{7}\times 10^{7}~(V_{\rm D}=1~{\rm V},~{\rm V}_{\rm G}=3~{\rm V})$ .