Finfet SRAM cell using low mobility plane for cell stability and method for forming

US6967351B2 · kind B2 · utility

Assignee

• International Business Machines Corporation · US

Inventors

• David M. Fried · Ithaca, US
• Randy W. Mann · Jericho, US
• K. Paul Muller · Wappingers Falls, US
• Edward J. Nowak · South Burlington, US

Key dates

• Filing date: Dec 4, 2001
• Grant date: Nov 22, 2005
• Expiry date: Mar 25, 2022

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S257/903

Abstract

The present invention provides a device design and method for forming the same that results in Fin Field Effect Transistors having different gains without negatively impacting device density. The present invention forms relatively low gain FinFET transistors in a low carrier mobility plane and relatively high gain FinFET transistors in a high carrier mobility plane. Thus formed, the FinFETs formed in the high mobility plane have a relatively higher gain than the FinFETs formed in the low mobility plane. The embodiments are of particular application to the design and fabrication of a Static Random Access Memory (SRAM) cell. In this application, the bodies of the n-type FinFETs used as transfer devices are formed along the {110} plane. The bodies of the n-type FinFETs and p-type FinFETs used as the storage latch are formed along the {100}. Thus formed, the transfer devices will have a gain approximately half that of the n-type storage latch devices, facilitating proper SRAM operation.