SEMICONDUCTOR DEVICE AND SEMICONDUCTOR DEVICE MANUFACTURING METHOD

摘要

PROBLEM TO BE SOLVED: To manufacture a semiconductor device which reduces parasitic resistance and inhibits decrease in on-state current.SOLUTION: A semiconductor device manufacturing method comprises: forming an oxide semiconductor layer; forming a gate insulation layer on the oxide semiconductor layer; forming a gate electrode layer which overlaps the oxide semiconductor layer via the gate insulation layer; forming a first insulation layer so as to cover the gate insulation layer and the gate electrode layer; introducing an impurity element from above the first insulation layer to form a pair of impurity regions in the oxide semiconductor layer; forming a second insulation layer on the first insulation layer; performing anisotropic etching on the first insulation layer and the second insulation layer to form a side wall insulation layer which contacts lateral faces of the gate electrode layer; and forming a source electrode layer and a drain electrode layer, which contact the pair of impurity regions, respectively.