Minority carrier lifetime control in power semiconductor devices by fast neutron irradiation

A new technology for controlling reduction of minority carrier lifetime of power semiconductor devices, using fast neutron irradiation in a nuclear reactor, is described. The effects on high frequency thyristors of fast neutron irradiation is discussed. A comparison is made with electron irradiated, 60Co-Gamma irradiated and gold diffused devices. The conclusion is that the trade-off of forward voltage drop and turn-off time of fast neutron irradiated devices is similar to that of gold diffused devices, while the leakage current is less than that of gold diffused devices, and similar to electron or gamma irradiated devices. The deep energy levels of fast neutron irradiation in silicon is shown in this paper, and a single dominant level of Ec-0.44eV is identified for controlling minority carrier lifetime. (author)