Laterally-diffused metal-oxide-semiconductor devices with a multiple-thickness buffer dielectric layer

Abstract

Structures for a laterally-diffused metal-oxide-semiconductor device and methods of forming a structure for a laterally-diffused metal-oxide-semiconductor device. The structure includes a drift well in a semiconductor substrate, source and drain regions in the semiconductor substrate, a gate dielectric layer on the semiconductor substrate, and a buffer dielectric layer on the semiconductor substrate over the drift well. The buffer dielectric layer includes a first side edge adjacent to the drain region, a second side edge adjacent to the gate dielectric layer, a first section extending from the second side edge to the first side edge, and a plurality of second sections extending from the second side edge toward the first side edge. The first section has a first thickness, and the second sections have a second thickness less than the first thickness. A gate electrode includes respective portions that overlap with the buffer dielectric layer and with the gate dielectric layer.