Forming gate oxides having multiple thicknesses

US7160771B2 · kind B2 · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Anthony I. Chou · Beacon, US
• Michael P. Chudzik · Beacon, US
• Toshiharu Furukawa · South Burlington, US
• Oleg Gluschenkov · Poughkeepsie, US
• Paul Kirsch · Fishkill, US
• Byoung Hun Lee · Wappingers Falls, US
• Katsunori Onishi · Fishkill, US
• Heemyoung Park · Lagrangeville, US
• Kristen Scheer · Milton, US
• Akihisa Sekiguchi · Briarcliff Manor, US

Key dates

• Filing date: Nov 28, 2003
• Grant date: Jan 9, 2007
• Expiry date: Jan 7, 2024

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D84/0181

Abstract

Gate oxides having different thicknesses are formed on a semiconductor substrate by forming a first gate oxide on the top surface of the substrate, forming a sacrificial hard mask over a selected area of the first gate oxide; and then forming a second gate oxide. A first poly layer may be formed on the first gate oxide, under the hard mask. After the hard mask is removed, a second poly layer may be formed over the second gate oxide and over the first poly layer. This enables the use of high-k dielectric materials, and the first gate oxide can be thinner than the second gate oxide.