Patent ID: 9741842
Date: 2017-08-22
CPC Classifications: H01L

Claim:
1. A transistor device comprising: a substrate; a drift layer on the substrate; a spreading layer on the drift layer, the spreading layer comprising a plurality of epitaxial layers between a first surface adjacent to the drift layer and a second surface opposite the first surface, wherein each one of the plurality of epitaxial layers has a different doping concentration such that a doping concentration of the spreading layer varies in a substantially continuous fashion from the first surface to the second surface and a ratio of the doping concentration at the first surface to the doping concentration at the second surface is 1:x where x is greater than or equal to 2; and a gate, a drain, and a source; wherein a channel width of the transistor device is less than 3 microns, an on-state resistance of the transistor device is less than 2.5 mΩ/cm