MOS transistor that inhibits punchthrough and method for fabricating the same

摘要

A MOS transistor that includes: a semiconductor substrate; a well region formed in the semiconductor substrate, where a trench region is defined in the well region; an isolator formed on a corner of the trench region, where the trench region is filled with polysilicon; a gate conductor formed over the trench region; and source/drain regions formed within the well region laterally aligned to the gate conductor. A suitable method to form the MOS transistor includes the acts of: forming a well region in a semiconductor substrate; forming a trench region in the well region; forming an isolator in a corner of the trench region; filling the trench region with polysilicon; forming a gate conductor formed over the trench region; and forming source/drain regions within the well region on opposite sides of the gate conductor.