RESEARCH ARTICLE

A non-destructive channel stress characterization for gate-all-around nanosheet transistors by confocal Raman methodology

¹ School of Microelectronics, Fudan University, Shanghai 200433, China
² Shanghai Integrated Circuit Manufacturing Innovation Center Company Ltd., Shanghai 200433, China
³ Zhangjiang Fudan International Innovation Center, Shanghai 200433, China
⁴ WITec (Beijing) Scientific Technology Co., Ltd., Beijing 100027, China

^* Corresponding authors (emails: xu_min@fudan.edu.cn (Min Xu); chen_w@fudan.edu.cn (Chen Wang); dwzhang@fudan.edu.cn (David Wei Zhang))

Received: 14 April 2022
Revised: 14 July 2022
Accepted: 8 August 2022

Abstract

Non-destructive stress characterization is essential for gate-all-around (GAA) nanosheet (NS) transistors technology, while it is a big challenge to be realized on nanometer-sized GAA devices by using traditional Micro-Raman spectroscopy due to its light spot far exceeding the device. In this work, a non-destructive stress characterization methodology of confocal Raman spectroscopy was proposed and performed for GAANS device fabrication. Channel stress evolution along the fabrication process was successfully characterized by designing high-density NS array and analyzing the linear scanned spectra in different structures. The related mechanism of stress evolution was systematically studied by Sentaurus process simulation. Additionally, applying this methodology on detecting the bending of suspended NS after channel release process was demonstrated. Therefore, this work might provide a promising solution to realize in-line characterization of channel stress in GAA NS transistors and process monitor of NS channel integrity.