Method for making vertical MOS having a deep source region near the channel

Abstract

A semiconductor device includes a first region, a well-shaped second region formed in the first region and a third region formed in the well-shaped second region, both the first region and the third region have a first conductive type, the well-shaped second region has a second conductive type. A gate electrode is formed on a channel of the well-shaped second region. The channel is sandwiched between the first region and the third region. According to the present invention, the depth of the third region is very deep in a portion near the channel and is very shallow in a portion far from the channel. A resistance of the well-shaped second region near a portion of the third region far from the channel is lower than near the portion of the third region near the channel.

Dependencies are inferred from the claim text.