Semiconductor device having drift regions of opposite conductivity types

摘要

A semiconductor device which eases an electric field at a drift portion without a reduction in impurity concentrations, and has a high withstand voltage and a low on-resistance, wherein, when a rated voltage is applied between a body region and a drain region formed on an insulating semiconductor substrate, the thicknesses of two, p-type and n-type, drift regions sandwiched between the body and drain regions are selected so as to completely deplete the drift regions. <IMAGE>