title: Investigation on the corner effect of L-shaped tunneling field-effect transistors and their fabrication method.
abstract: In this work, electrical characteristics of L-shaped tunneling field-effect transistors (TFETs) have been studied and optimized by a commercial device simulator: Synopsys Sentaurus. Unlike our previous study performed by using Silvaco Atlas, there exists a kink phenomenon in a transfer curve which degrades the subthreshold swing (SS) and on-current (lon) of TFETs. According to simulation results, the kink results from abrupt source doping. Rounding the source junction edge with gradual doping profile is helpful to alleviate it. Based on those results, a novel fabrication flow has been proposed to suppress the kink effect induced by source corners. It is predicted that the performance of L-shaped TFETs is improved in terms of SS and Ion under the optimized process condition. Furthremore, the effect of high-k gate dielectric and narrow band gap material on device performance has been examined. Using 2-nm-thick HfO2 for gate dielectric and Si0.7Ge0.3 for intrinsic tunneling region, gate controllability to the channel and tunneling probability have been enhanced. As a result, its threshold voltage (Vth), SS and Ion have been improved by 0.13 V, 16 mV/dec, and 3.62 microA/microm, respectively.
authors.affiliation: Inter-University Semiconductor Research Center (ISRC) and School of Electrical Engineering and Computer Science, Seoul National University, Seoul 151-742, Korea.
authors.forename: Sang Wan
authors.initials: SW
authors.lastname: Kim
authors.forename: Woo Young
authors.initials: WY
authors.lastname: Choi
authors.forename: Min-Chul
authors.initials: MC
authors.lastname: Sun
authors.forename: Byung-Gook
authors.initials: BG
authors.lastname: Park