SEMICONDUCTOR DEVICE AND METHOD OF MANUFACTURING SAME

摘要

PROBLEM TO BE SOLVED: To reduce JFET resistance value of a semiconductor device having a broad buffer structure. SOLUTION: In the semiconductor device, a N-drift layer 1 has at least one portion whose net doping concentration becomes maximum. The net doping concentration of the N-drift layer 1 becomes low from a portion that the doping concentration becomes maximum to both P base region 2 and N+collector buffer layer 4. Out of surface layers at a first main surface side of the N-drift layer 1 having a predetermined depth, a second conductive impurity is more deeply introduced in a region not in contact with a gate insulation film 6 than in a second conductive base region. Further, out of surface layers having a predetermined depth at a first main surface side of the N-drift layer 1, the net doping concentration in contact with the gate insulation film 6 is higher than that of the region not in contact with the gate insulation film 6. COPYRIGHT: (C)2008,JPO&INPIT