Self-aligned uniform bottom spacers for VTFETS

US11251287B2 · kind B2 · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Ruilong Xie · Niskayuna, US
• Hemanth Jagannathan · Niskayuna, US
• Jay William Strane · Wappingers Falls, US
• Eric R. Miller · Schenectady, US

Key dates

• Filing date: Apr 14, 2020
• Grant date: Feb 15, 2022
• Expiry date: Apr 14, 2040

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D84/013

Abstract

Semiconductor devices and methods of forming the same include forming a bottom source/drain structure around a fin. A multi-layer bottom spacer is formed on the bottom source/drain structure, around the fin. Each layer of the multi-layer bottom spacer has a respective vertical height above the bottom source/drain structure, with a layer of the multi-layer bottom spacer that is farthest from the fin having a greater vertical height than a layer that is closest to the fin, to address parasitic capacitance from the bottom source/drain structure.