Demonstration of Germanium Vertical Gate-All-Around Field-Effect Transistors Featured by Self-Aligned High-κ Metal Gates with Record High Performance.

Xie, Lu; Zhu, Huilong; Zhang, Yongkui; Ai, Xuezheng; Li, Junjie; Wang, Guilei; Liu, Jinbiao; Du, Anyan et al. · ACS Nano · 2023

basic_science · Level V

Where this comes from

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>I</i><sub>on</sub> 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.