Nanosheet substrate to source/drain isolation

US10734523B2 · kind B2 · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Fee Li Lie · Albany, US
• Mona A. Ebrish · Albany, US
• Ekmini Anuja De Silva · Slingerlands, US
• Indira Seshadri · Niskayuna, US
• Gauri Karve · Cohoes, US
• Lawrence A. Clevenger · Saratoga Springs, US
• Leigh Anne H. Clevenger · Rhinebeck, US
• Nicolas Loubet · Guilderland, US

Key dates

• Filing date: Aug 13, 2018
• Grant date: Aug 4, 2020
• Expiry date: Oct 9, 2038

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B82Y40/00
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

A method of forming a nanosheet device is provided. The method includes forming a nanosheet channel layer stack and dummy gate structure on a substrate. The method further includes forming a curved recess in the substrate surface adjacent to the nanosheet channel layer stack. The method further includes depositing a protective layer on the curved recess, dummy gate structure, and exposed sidewall surfaces of the nanosheet layer stack, and removing a portion of the protective layer on the curved recess to form a downward-spiked ridge around the rim of the curved recess. The method further includes extending the curved recess deeper into the substrate to form an extended recess, and forming a sacrificial layer at the surface of the extended recess in the substrate.