Semiconductor device with composite drift region

摘要

A device includes a semiconductor substrate, a channel region in the semiconductor substrate having a first conductivity type, and a composite drift region in the semiconductor substrate, having a second conductivity type. The composite drift region includes a first drift region and a second drift region spaced from the channel region by the first drift region. The device further includes a drain region in the semiconductor substrate, spaced from the channel region by the composite drain region, and having the second conductivity type. The first drift region has a dopant concentration profile with a first concentration level where adjacent the channel region and a second concentration level where adjacent the second drift region, the first concentration level being higher than the second concentration level. In some embodiments, the first and second drift regions are stacked vertically, with the first drift region being shallower than the second drift region.

主权项

1. A device comprising:
a semiconductor substrate; a body region in the semiconductor substrate having a first conductivity type and a channel region; a composite drift region in the semiconductor substrate, having a second conductivity type, and comprising a first well and a second well spaced from the channel region by the first well; and a drain region in the semiconductor substrate, spaced from the channel region by the composite drift region, and having the second conductivity type; wherein the first well has a dopant concentration profile with a first concentration level at a surface of the semiconductor substrate where the first well is adjacent the channel region and a second concentration level where the first well is adjacent the second well, the first concentration level being higher than the second concentration level; and wherein the first and second wells are connected with one another where the first well has the second concentration level, and not connected with one another where the first well has the first concentration level.