| 摘要 |
Proton irradiation is performed a plurality of times from the rear surface of an n-type semiconductor substrate, which is an n - drift layer, to form an n-type FS layer which has a lower resistance than the n-type semiconductor substrate in the rear surface of the n - drift layer. When the proton irradiation is performed a plurality of times in order to form the n-type FS layer, the next proton irradiation is performed to as to compensate for a reduction in mobility due to disorder (7) which remains in the previous proton irradiation. In this case, the second or subsequent proton irradiation is performed at the position of the disorder (7) which is formed by the previous proton irradiation. In this way, even after proton irradiation and a heat treatment, the disorder (7) is reduced and it is possible to prevent deterioration of characteristics, such as an increase in leakage current. In addition, it is possible to form an n-type FS layer including a high-concentration hydrogen-related donor layer. |
