SOI LATERAL MOSFET DEVICES
First Claim
1. An SOI lateral MOSFET device comprisinga semiconductor substrate layer,a dielectric buried layer,on said semiconductor substrate layer,an active layer on said dielectric buried layer,a trench gate in said active layer, consisting of gate dielectric and conductive material surrounded by the gate dielectric, wherein the terminal of said conductive material is trench gate electrode,wherein, the trench gate going through the active layer to said dielectric buried layer, a drain region and a body region separating from each other on said active layer surface on a side of said trench gate, and drain electrode acting as the drain region terminal,source region a, body contact region and source region b on the surface of said body region in sequence, with a source electrode as their common terminal,said body region and source region a is in contact with said trench gate,a dielectric trench located between said source region b and said drain region, being in contact with said body region and source region b, wherein the permittivity of the dielectric in said dielectric trench is lower than that of the material of said active layer, the depth of the said dielectric trench is larger than that of the body region and less than the thickness of the active layer,a buried gate of conductive material inset in said dielectric trench in the vicinity of the source region b and surrounded by the dielectric in said dielectric trench, with a depth no less than that of said body region and less than that of dielectric trench, the terminal of said buried gate is the buried gate electrode,said trench gate electrode and buried gate electrode are connected electrically, and the common terminal of said trench gate electrode and buried gate electrode is a gate electrode.
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Accused Products
Abstract
The present invention relates to a semiconductor power device and power integrated circuits (ICs). The lateral SOI MOSFET in the present comprises a trench gate extended to the dielectric buried layer, one or multiple dielectric trenches in the drift region, and a buried gate in said dielectric trench. The permittivity of the dielectric in said dielectric trench is lower than that of said active layer. Firstly, said dielectric trench not only greatly improves breakdown voltage, but also reduces pitch size. Secondly, the trench gate widens the effective conductive region in the vertical direction. Thirdly, dual gates of said trench gate and buried gate increase channel and current densities. Thereby, specific on-resistance and the power loss are reduced. The device of the present invention has many advantages, such as high voltage, high speed, low power loss, low cost and ease of integration. The device in the present invention is particularly suitable for power integrated circuits and RF power integrated circuits.
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Citations
19 Claims
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1. An SOI lateral MOSFET device comprising
a semiconductor substrate layer, a dielectric buried layer,on said semiconductor substrate layer, an active layer on said dielectric buried layer, a trench gate in said active layer, consisting of gate dielectric and conductive material surrounded by the gate dielectric, wherein the terminal of said conductive material is trench gate electrode, wherein, the trench gate going through the active layer to said dielectric buried layer, a drain region and a body region separating from each other on said active layer surface on a side of said trench gate, and drain electrode acting as the drain region terminal, source region a, body contact region and source region b on the surface of said body region in sequence, with a source electrode as their common terminal, said body region and source region a is in contact with said trench gate, a dielectric trench located between said source region b and said drain region, being in contact with said body region and source region b, wherein the permittivity of the dielectric in said dielectric trench is lower than that of the material of said active layer, the depth of the said dielectric trench is larger than that of the body region and less than the thickness of the active layer, a buried gate of conductive material inset in said dielectric trench in the vicinity of the source region b and surrounded by the dielectric in said dielectric trench, with a depth no less than that of said body region and less than that of dielectric trench, the terminal of said buried gate is the buried gate electrode, said trench gate electrode and buried gate electrode are connected electrically, and the common terminal of said trench gate electrode and buried gate electrode is a gate electrode.
Specification