Patent ID: 9184282
Filing Date: 2015-11-10
Classification: H01L

Abstract:
1. A semiconductor device comprising: a first well region of a first conductivity type in a top surface of a substrate, the top surface of the substrate comprising a curved surface; a second well region of a second conductivity type in the top surface of the substrate, the second conductivity type being opposite the first conductivity type, the second well region laterally separated from the first well region by a first portion of the substrate; a first field oxide region in the first well region, the first field oxide region having a first bottom surface, wherein the first field oxide region directly contacts a lower portion of the curved surface of the substrate; a second field oxide region in the second well region, the second field oxide region having a second bottom surface, the first bottom surface being lower than the second bottom surface; and a gate on the first well region and the second well region, wherein a portion of the gate fills a gap between the first field oxide region and an upper portion of the curved surface of the substrate.