Area efficient floating field ring termination

US10629677B2 · kind B2 · utility

Assignee

• ABB Schweiz AG · CH

Inventors

• Friedhelm Bauer · Suhr, CH
• Umamaheswara Vemulapati · Windisch, CH

Key dates

• Filing date: May 29, 2018
• Grant date: Apr 21, 2020
• Expiry date: May 29, 2038

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D62/8503

Abstract

A high power semiconductor device with a floating field ring termination includes a wafer, wherein a plurality of floating field rings is formed in an edge termination region adjacent to a first main side surface of the wafer. At least in the termination region a drift layer, in which the floating field rings are formed, includes a surface layer and a bulk layer wherein the surface layer is formed adjacent to the first main side surface to separate the bulk layer from the first main side surface and has an average doping concentration which is less than 50% of the minimum doping concentration of the bulk layer. The drift layer includes a plurality of enhanced doping regions, wherein each one of the enhanced doping regions is in direct contact with a corresponding one of the floating field rings at least on a lateral side of this floating field ring, which faces towards the active region. The relatively low doped surface layer and the enhanced doping regions increase the electric field coupling from floating field ring to floating field ring, thus allowing an area efficient termination structure. Each enhanced doping region extends to at least the same depth as the one of the corres…