FET with stable threshold voltage and method of manufacturing the same

US5675166A · kind A · utility

Assignee

• Motorola, Inc. · US

Inventors

• Vida Ilderem · Phoenix, US
• Michael H. Kaneshiro · Chandler, US
• Diann Dow · Chandler, US

Key dates

• Filing date: Jul 7, 1995
• Grant date: Oct 7, 1997
• Expiry date: Jul 7, 2015

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D64/021

Abstract

A low voltage field effect transistor structure (20) is provided with a threshold voltage that is tolerant of process variations that alter the location of a source implant region (41). A first halo region (33) and a second halo region (36) are formed adjacent to source region (41) such that after subsequent thermal processing, a constant doping profile of opposite conductivity as source region (41) is formed in the channel region (23) adjacent the source region (41). The embodiments can be formed either adjacent to only the source region (41) to create a unilateral device, or the doping profile can be formed adjacent to both source region (41) and a drain region (40) to produce a bilateral device. An additional embodiment forms a second implant region in source region (41) to reduce junction leakage and capacitance.