Patent ID: 8198677
Filing Date: 2012-06-12
Classification: H01L

Abstract:
1. A field effect transistor comprising: a first silicon region comprising a body region having a first conductivity type, the first silicon region having a top surface; a gate-trench region extending from the top surface of the first silicon region into the first silicon region, wherein the gate-trench region has a first sidewall, a bottom, and a second sidewall, the gate-trench region having: a highly-doped drain region of a second conductivity type at the top surface of the first silicon region and contacting a drain electrode, the highly-doped drain region being laterally spaced from the gate-trench region, the second conductivity type being opposite to the first conductivity type; a lightly-doped drain region of the second conductivity type in the first silicon region, the lightly-doped drain region laterally extending along the top surface of the first silicon region between the second sidewall of the gate-trench region and the highly-doped drain region, and further extending under the bottom of the gate-trench region; and wherein a portion of the lightly-doped drain region laterally extending along the top surface of the first silicon region extends to a depth shallower than a bottom of the gate-trench region.