Patent ID: 11876134
Assignee: TEXAS INSTRUMENTS INCORPORATED
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 11:
12. A semiconductor device, comprising:
an n-type source region in a semiconductor substrate;, an n-type drain region having a first dopant concentration spaced apart from the source region;
an n-type drift region located between the source region and the drain region and having a second dopant concentration that is lower than the first dopant concentration;
a p-type channel region between the source region and the drift region;
a LOCOS structure between the channel region and the drain region including a first portion on or over the drift region and a tapered portion between the first portion and the drain region;
a substrate surface extension between the tapered portion and the n-type drain region;
a gate structure on or over the LOCOS structure and including a portion over the channel region; and
a buffer region between the drift region and the drain region and under the tapered portion of the LOCOS structure, the buffer region having a dopant concentration that increases no more than 10×from the drift region towards the drain region.