Patent ID: 7265426

Claim:
A high-voltage MOS transistor, comprising: a first region of a first conductivity type; at least one source region of a second conductivity type and being introduced into the first region; a drain region of the second conductivity type and being introduced into the first region; a channel region on an upper side of the first region, between the at least one source region and the drain region; at least one field-oxide region in the drain region between the at least one source region and the drain region; a gate-oxide region located over the channel region and between an edge of the drain region and the at least one field-oxide region; and a magnetoresistor region located between the at least one source region and the drain region and above the gate-oxide region, and above at least part of the at least one field-oxide region, wherein: the drain region includes a drain-terminal region and a drain-extension region, a doping profile of the drain-extension region is designed so that an avalanche breakdown occurs between the at least one source region and the drain region, in a breakdown region that is on an edge of the drain-extension region and is not situated at an upper surface.