Patent ID: 6777746
Filing Date: 2004-08-17
Classification: H01L

Abstract:
A field effect transistor comprising:a base layer of a first conductivity type formed on a surface of a substrate; a source layer of a second conductivity type selectively formed on a surface of the base layer; a drain layer of a second conductivity type formed on the substrate apart from the base layer; a drift semiconductor layer of the first conductivity type extended from the base layer to the drain layer in a region between the base layer and the drain layer; a drift semiconductor layer of the second conductivity type formed together with the drift semiconductor layer of the first conductivity type, wherein the drift semiconductor layer of the first conductivity type and the drift semiconductor layer of the second conductivity type are alternately arranged; and a gate electrode formed on the base layer and on at least half of surfaces of the drift semiconductor layers via a gate insulating film, wherein assuming an impurity dose of the drift semiconductor layer of the first conductivity type or the drift semiconductor layer of the second conductivity type as &PHgr; and a stripe width as W, a following relation is held between the values: &PHgr;Ã—W&lE;1Ã—108(cmâˆ’1).