Device structure and methods of making high density MOSFETs for load switch and DC-DC applications

US9136380B2 · kind B2 · utility

Assignee

• Alpha and Omega Semiconductor, Ltd. · US

Inventors

• Hamza Yilmaz · Saratoga, US
• Madhur Bobde · Sunnyvale, US
• Hong Chang · Saratoga, US
• Yeeheng Lee · San Jose, US
• Daniel Calafut · San Jose, US
• Jongoh Kim · Hsinchu, TW
• Sik Lui · Sunnyvale, US
• John Chen · Palo Alto, US

Key dates

• Filing date: Jul 11, 2014
• Grant date: Sep 15, 2015
• Expiry date: Jul 11, 2034

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D64/62

Abstract

Aspects of the present disclosure describe a high density trench-based power MOSFETs with self-aligned source contacts and methods for making such devices. The source contacts are self-aligned with spacers that are formed along the sidewall of the gate caps. Additionally, the active devices may have a two-step gate oxide. A lower portion may have a thickness that is larger than the thickness of an upper portion of the gate oxide. The two-step gate oxide combined with the self-aligned source contacts allow for the production of devices with a pitch in the deep sub-micron level. It is emphasized that this abstract is provided to comply with rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.