Patent ID: 7839209
Filing Date: 2010-11-23
Classification: H01L

Abstract:
1. A semiconductor device, comprising: a source diffusion of a first conductivity type at a first major surface of the semiconductor device; a drain diffusion a second conductivity type opposite to the first conductivity type laterally spaced from the source diffusion at the first major surface; a lower doped region between the source diffusion and the drain diffusion at the first major surface, the lower doped region having a lower dopant concentration than the source diffusion and the drain diffusion; an insulated gate on the first major surface over the lower doped region; wherein the semiconductor device includes a cap layer of a first semiconductor material at the first major surface, an accumulation layer formed under the cap layer of a second semiconductor material different to the first semiconductor material, and a lower layer under the accumulation layer of a different material to the second semiconductor material to form a quantum well for confining electrons, holes, or both in the accumulation layer.