Stepped trench MOSFET and method of fabricating the same

US8841721B2 · kind B2 · utility

Assignee

• Industrial Technology Research Institute · TW

Inventors

• Cheng-Tyng Yen
• Chien-Chung Hung · Hsinchu, TW
• Young-Shying Chen · Hsinchu, TW
• Chwan-Ying Lee · Tainan, TW

Key dates

• Filing date: May 7, 2013
• Grant date: Sep 23, 2014
• Expiry date: May 7, 2033

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D64/516

Abstract

A step trench metal-oxide-semiconductor field-effect transistor comprises a drift layer, a first semiconductor region, a stepped gate and a floating region. The drift layer is of a first conductivity type. The first semiconductor region is of a second conductivity type and located on the drift layer, wherein the drift layer and the first semiconductor region have a stepped gate trench therein. The stepped gate trench at least comprises a first recess located in the first semiconductor region and extending into the drift layer and a second recess located below a bottom of the first recess, wherein a width of the second recess is smaller than a width of the first recess. A floating region is of the second conductivity type and located in the drift layer below the second recess.