Method of forming a silicon-carbide device with a shielded gate

US9577073B2 · kind B2 · utility

Assignee

• Infineon Technologies AG · DE

Inventors

• Romain Esteve · Munich, DE
• Dethard Peters · Edenkoben, DE
• Wolfgang Bergner · Waldbüttelbrunn, DE
• Ralf Siemieniec · Villach, AT
• Thomas Aichinger · Faak am See, AT
• Daniel Kueck · Villach, AT

Key dates

• Filing date: Dec 11, 2014
• Grant date: Feb 21, 2017
• Expiry date: Dec 11, 2034

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L21/3065
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

A silicon-carbide semiconductor substrate having a plurality of first doped regions being laterally spaced apart from one another and beneath a main surface, and a second doped region extending from the main surface to a third doped region that is above the first doped regions is formed. Fourth doped regions extending from the main surface to the first doped regions are formed. A gate trench having a bottom that is arranged over a portion of one of the first doped regions is formed. A high-temperature step is applied to the substrate so as to realign silicon-carbide atoms along sidewalls of the trench and form rounded corners in the gate trench. A surface layer that forms along the sidewalls of the gate trench during the high-temperature step from the substrate is removed.