Method of forming shallow junctions in field effect transistors

US5268317A · kind A · utility

Assignee

• Siemens Aktiengesellschaft · DE

Inventors

• Udo Schwalke · Heldenstein, DE
• Christoph Zeller · Ottobrunn, DE
• Heinrich Zeininger · Obermichelbach, DE
• Wilfried Hansch · South Burlington, US

Key dates

• Filing date: Nov 12, 1991
• Grant date: Dec 7, 1993
• Expiry date: Nov 12, 2011

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D64/259
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

A method of making a MOS field effect transistor having shallow source and drain regions with improved breakdown and leakage characteristics includes the step of forming a layer of a metal silicide along a surface of a body of silicon at each side of a gate which is on an insulated from the surface. A high concentration of an impurity of a desired conductivity type is implanted only into the metal silicide layers. A lower concentration of the impurity is then implanted through the metal silicide layers and into the body just beneath the metal silicide layers. The body is then annealed at a temperature which drives the impurities from the metal silicide layer into the body to form the junctions.