The reverse recovery time of a silicon epitaxial high current diode with p+ nn,+, type is substantially reduced by irradiation with 1.2 MeV electons, while the forward voltage drop of the device is maintained within nominal ranges. The present process technology is provided by positioning the diode semiconductor having soldered joint to the holder but still unsealed with the cap with the major surface adjoining the anode region of the device for exposure to a radiation source, and thereafter the device is irradiated by electrons at room temprature. The electron flux is about 5×10,13, to 9×10,14,e,-,/cm,2, and most desirably about 3~5×10,14,e/cm,2,. The electrical characteristics of the device were measured before and after irradiation. The irradiated devices sealed with the cap were stored at 150℃ and were tested electrically for a period of 240 hours. The irradiated devices have good characteristics. Now the present process technology have introduced into production.