Ion implantation combined with in situ or ex situ heat treatment for improved field effect transistors

US7968459B2 · kind B2 · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Stephen W. Bedell · Wappingers Falls, US
• Joel P. Desouza · Putnam Valley, US
• Zhibin Ren · Hopewell Junction, US
• Alexander Reznicek · Troy, US
• Devandra K. Sadana · Pleasantville, US
• Katherine L. Saenger · Ossining, US
• Ghavam G. Shahidi · Pound Ridge, US

Key dates

• Filing date: May 28, 2008
• Grant date: Jun 28, 2011
• Expiry date: Feb 13, 2029

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S438/943
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

This invention teaches methods of combining ion implantation steps with in situ or ex situ heat treatments to avoid and/or minimize implant-induced amorphization (a potential problem for source/drain (S/D) regions in FETs in ultrathin silicon on insulator layers) and implant-induced plastic relaxation of strained S/D regions (a potential problem for strained channel FETs in which the channel strain is provided by embedded S/D regions lattice mismatched with an underlying substrate layer). In a first embodiment, ion implantation is combined with in situ heat treatment by performing the ion implantation at elevated temperature. In a second embodiment, ion implantation is combined with ex situ heat treatments in a “divided-dose-anneal-in-between” (DDAB) scheme that avoids the need for tooling capable of performing hot implants.