Power MOSFET with improved safe operating area

Abstract

A MOSFET device die includes an active area formed on a semiconductor substrate. The active area includes a first active area portion and a second active area portion. At least one mesa is formed in the semiconductor substrate extending in a longitudinal direction through the active area. The at least one mesa includes a channel region extending in a longitudinal direction. The channel region includes low threshold voltage channel portions and high threshold voltage channel portions. The first active area portion includes the channel portions in a first ratio of low threshold voltage channel portions to high threshold voltage channel portions, and the second active area portion includes channel portions in a second ratio of low threshold voltage channel portions to high threshold voltage channel portions. The first ratio is larger than the second ratio.

Dependencies are inferred from the claim text.