Semiconductor device and method for producing semiconductor device

摘要

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

主权项

1. A semiconductor device comprising:
a breakdown voltage holding pn junction that is provided in one main surface of an n-type semiconductor substrate; and an n-type field stop layer that is provided in the other main surface of the n-type semiconductor substrate, has a lower resistance than the n-type semiconductor substrate, and suppresses the spreading of a depletion layer from the breakdown voltage holding pn junction, wherein the n-type field stop layer has an impurity concentration distribution which includes a plurality of impurity concentration peaks at different positions in a depth direction of the n-type semiconductor substrate, among the plurality of impurity concentration peaks, a first impurity concentration peak closest to the one main surface of the n-type semiconductor substrate is disposed at a depth of 15 μm or more from the other main surface of the n-type semiconductor substrate, and a distance between the position of a second impurity concentration peak in the n-type field stop layer and the other main surface of the n-type semiconductor substrate is equal to or more than half of a distance between the position of the first impurity concentration peak and the other main surface of the n-type semiconductor substrate.