Patent ID: 6198131
Filing Date: 2001-03-06
Classification: H01L

Abstract:
A high-voltage metal oxide semiconductor device, comprising:a P-type region;a gate on the P-type region;an N-type source region and an N-type drain region in the P-type region, aside of the gate;a field oxide layer, under a part of the gate to isolate the gate and the N-drain region;an N-type drift region, under the field oxide layer;a first P-well, encompassing the N-type source region in the P-type region;a second P-well, encompassing the first P-well in the P-type region;a first N-well, encompassing the N-type drain region in the P-type region; anda second N-well, encompassing the first N-well in the P-type region; whereinthe first P-well has a dopant concentration higher than that of the second P-well.