Method to form stepped dielectric for field plate formation

摘要

A semiconductor device is formed with a stepped field plate over at least three sequential regions in which a total dielectric thickness under the stepped field plate is at least 10 percent thicker in each region compared to the preceding region. The total dielectric thickness in each region is uniform. The stepped field plate is formed over at least two dielectric layers, of which at least all but one dielectric layer is patterned so that at least a portion of a patterned dielectric layer is removed in one or more regions of the stepped field plate.

主权项

1. A semiconductor device, comprising:
a semiconductor substrate; a first field plate area defined over said substrate, a second field plate area defined over said substrate adjacent to said first field plate area, and a third field plate area defined over said semiconductor substrate adjacent to said second field plate area; a first dielectric layer disposed over said semiconductor substrate, of which at least a portion of said first dielectric layer is absent in at least one of said first field plate area, said second field plate area and said third field plate area; a second dielectric layer disposed over said first dielectric layer and over said semiconductor substrate; and a stepped field plate disposed over said first dielectric layer and said second dielectric layer in said first field plate area, said second field plate area and said third field plate area, in which:
a total dielectric thickness in said second field plate area between said stepped field plate and said semiconductor substrate is at least 10 percent more than a total dielectric thickness in said first field plate area between said stepped field plate and said semiconductor substrate; anda total dielectric thickness in said third field plate area between said stepped field plate and said semiconductor substrate is at least 10 percent more than a total dielectric thickness in said second field plate area between said stepped field plate and said semiconductor substrate.