20110284953 | POWER TRENCH MOSFET RECTIFIER - A trench MOSFET rectifier includes oxide layers having different thicknesses formed in different regions of the devices. The rectifying device also includes a source region of first conductivity type at a surface of each mesa region and a body region of a second conductivity type beneath each source region. The rectifying device also includes a dielectric layer lining the bottom and sidewall surfaces of the trenches, the portion of the dielectric layer on the bottom surface being thicker than the portion on the sidewall surface. A doped region underlies each of the first plurality of trenches. A polycrystalline silicon region filling each of the first plurality of trenches to form a gate region in each trench. A conductive material fills a plurality of contact trenches and forms ohmic contacts with the source region, body region, and gate region. | 11-24-2011 |