Lightly-doped drain MOSFET with improved breakdown characteristics

US5374843A · kind A · utility

Assignee

• Silinconix, Inc. · US

Inventors

• Richard K. Williams · Cupertino, US
• Michael E. Cornell · Campbell, US
• Mike F. Chang · Cupertino, US
• David G. Grasso · San Jose, US
• Agnes Yeung · Saratoga, US
• Juiping Chuang · Cupertino, US

Key dates

• Filing date: Mar 31, 1993
• Grant date: Dec 20, 1994
• Expiry date: Mar 31, 2013

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L2924/0002
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

A high voltage integrated circuit (IC) has a passivation structure that shields the underlying circuit from the electrical effects of charge on the passivation structure. In one embodiment, the passivation structure comprises a silicon rich nitride layer in electrical contact with underlying circuit elements. The silicon rich nitride is highly resistive and permits only a negligible current between elements, but is conductive enough that charge on the surface of the passivation structure flows into the IC before the electric fields in the underlying circuit elements is significantly changed. In another embodiment, the passivation structure has two or more layers with a less conductive layer in contact with the underlying IC and overlying conductive layer which shields the IC from the effects of charge build up.