Demonstration of Germanium Vertical Gate-All-Around Field-Effect Transistors Featured by Self-Aligned High-κ Metal Gates with Record High Performance
Lu Xie, Huilong Zhu, Yongkui Zhang, Xuezheng Ai, Junjie Li, Guilei Wang, Jinbiao Liu, Anyan Du, Hong Yang, Xiaogen Yin, Weixing Huang, Chen Li, Yangyang Li, Qi Wang, Shunshun Lu, Zhenzhen Kong, Jinjuan Xiang, Yong Du, Jun Luo, Junfeng Li, Henry H. Radamson, Wenwu Wang, Tianchun Ye
Abstract
A special Ge nanowire/nanosheet (NW/NS) p-type vertical sandwich gate-all-around (GAA) field-effect transistor (FET) (Ge NW/NS pVSAFET) with self-aligned high-κ metal gates (HKMGs) is proposed. The Ge pVSAFETs were fabricated by high-quality GeSi/Ge epitaxy, an exclusively developed self-limiting isotropic quasi atomic layer etching (qALE) of Ge selective to both GeSi and the (111) plane, top-drain implantation, and ozone postoxidation (OPO) channel passivation. The Ge pVSAFETs, which have hourglass-shaped (111) channels with the smallest size range from 5 to 20 nm formed by qALE, have reached a record high I on of ∼291 μA/μm and exhibited good short channel effects (SCEs) control. The integration flow is compatible with mainstream CMOS processes, and Ge pVSAFETs with precise control of gate lengths/channel sizes were obtained.