Breakdown Voltage Enhancement of Nanosheet Transistors by Ultrathin Bodies
Journal
IEEE Electron Device Letters
Date Issued
2024-01-01
Author(s)
Huang, Bo Wei
Hsieh, Wan Hsuan
Tu, Chien Te
Liu, Yi Chun
Chen, Yu Rui
Cheng, Chun Yi
Chou, Hung Chun
Liu, C. W.
Abstract
A high breakdown voltage of 11.7 V is achieved for a GeSn ultrathin (~2 nm) body nanosheet p-channel field-effect transistor. This voltage is 5.7 V higher than that for a 10-nm GeSn nanosheet. The large effective bandgap associated with the quantum confinement in the ~2-nm Ge0.9Sn0.1 channel is responsible for the enhanced breakdown voltage. An extremely scaled Ge0.9Sn0.1 ultrathin body with channel thickness reduced to ~2 nm is realized through the co-optimization of low-temperature epitaxy and selective isotropic etching. As-grown Ge0.9Sn0.1 channel layers as thin as 4 nm sandwiched by Ge0.97Sn0.03/Ge caps are carefully designed for ultrathin bodies. Radical-based highly selective isotropic dry etching is adopted to etch the caps and sacrificial layers and to release the GeSn ultrathin body channels. In addition, owing to strong quantum confinement in the ~2-nm ultrathin body, a high ION/IOFF ratio of ≥1.7 × 107 at VDS = -0.5 V is achieved.
Subjects
breakdown voltage | caps | chemical vapor deposition | GeSn | nanosheet | quantum confinement | selective isotropic dry etching | ultrathin body
Type
journal article