Patent ID: 8575694
Filing Date: 2013-11-05
Classification: H01L

Abstract:
1. A high voltage semiconductor transistor, comprising: a lightly doped semiconductor substrate having a first type of conductivity, wherein a portion of the lightly doped semiconductor substrate includes an implanted oxygen layer below a top surface of the lightly doped semiconductor substrate; a first well region having a second type of conductivity and formed over the lightly doped semiconductor substrate; a second well region in the first well region and having the first type of conductivity; an insulating structure over and partially embedded in the first well region and not contacting the second well region; a gate structure near the insulating structure over the first well region; a drain region in the first well region across the insulating structure from the gate structure, the drain region comprising a first drain portion adjacent to the insulating structure and a second drain portion further away from the insulating structure, wherein the first drain portion has the first type of conductivity and the second drain portion has the second type of conductivity; a source region in the second well region disposed on a side of the gate structure opposite from the drain region; and a deep trench isolation feature in the first well region surrounding the second well region, the insulating structure, the gate structure, the source region, and the first drain portion, wherein the deep trench isolation feature contacts the implanted oxygen layer.