| 摘要 |
<p>Oxygen is introduced into an N<SUP>- </SUP>type wafer (10) to be an N<SUP>- </SUP>type first semiconductor layer, then, a P type second semiconductor layer (2) and an anode electrode (4) are formed on the front plane of the FZ wafer (10). The FZ wafer (10) is irradiated with protons from the side of the anode electrode (4), and crystal defects (12) are introduced into the FZ wafer (10). The net doping concentration at a part in the first semiconductor layer is permitted to be higher than the initial net doping concentration of the FZ wafer (10) by restoring the crystal defects (12) in the FZ wafer (10) by performing heat treatment, and a desired broad buffer structure is formed. Thus, a semiconductor device having high-speed, low-loss and soft switching characteristics is manufactured at a low cost with excellent controllability and high yield by using the FZ bulk wafer.</p> |
