Abstract: A silicon (Si)-on-insulator (SOI) high voltage transistor with a body ground is provided with an associated fabrication process. The method provides a SOI substrate with a buried oxide (BOX) layer and a Si top layer having a first thickness and a second thickness, greater than the first thickness. A body ground is formed in the second thickness of Si top layer overlying the BOX layer. A control channel is formed in the first thickness of the Si top layer. A control gate is formed overlying the control channel. An auxiliary channel is formed in the second thickness of Si top layer partially overlying the body ground and extending into the first thickness of the Si top layer. An auxiliary gate is formed overlying the auxiliary channel. A pn junction is formed in the second thickness of Si top layer between the auxiliary channel and the body ground.

Abstract: A method is provided for fabricating a silicon (Si)-on-insulator (SOI) double-diffused metal oxide semiconductor transistor (DMOST) with a stepped channel thickness. The method provides a SOI substrate with a Si top layer having a surface. A thinned area of the Si top layer is formed, and a source region is formed in the thinned Si top layer area. The drain region is formed in an un-thinned area of the Si top layer. The channel has a first thickness adjacent the source region with first-type dopant, and a second thickness, greater than the first thickness, adjacent the drain region. The channel also has a sloped thickness between the first and second thicknesses. The second and sloped thicknesses have a second-type dopant, opposite of the first-type dopant. A stepped gate overlies the channel.