LATERAL HIGH BREAKDOWN STRENGTH SEMICONDUCTOR ELEMENT

PURPOSE:To provide a lateral IGBT, with the structure suitable for high integration, which is not incapable of turning off. CONSTITUTION:An n-type active layer 3 provided on a silicon substrate 1 with a silicon oxide film 2 in between, a p-type base layer 5, selectively formed on the n-type active layer 3, reaching as far as the silicon oxide film 2, and an n-type source layer 7 selectively formed on the surface of p-type base layer 5, are provided. In addition, a gate electrode 9 provide on the p-type base layer 5 with a gate oxide film 8 in between, an n-type base layer 4, selectively formed on the n-type active layer 3, reaching as far as the silicon oxide film 2, and a p-type drain layer 5 selectively formed on the surface of the n-type base layer 4, are provided. Meanwhile, a semiconductor layer area 12 containing the n-type base layer 4 and a p-type drain layer 6 is made to be thicker than the area of the n-type active layer 3 other than the semiconductor layer area 12.