Electron irradiation was performed to enhance the switching speed and thereby to reduce the energy loss of a p-n junction diode. The reverse recovery time decreased significantly but other electrical deterioration such as leakage current and on-stage voltage drop due to the electron irradiation was found not to be much. Also the defect distribution and the type of the electron irradiation-induced defects are discussed based on the deep level transient spectroscopy (DLTS) analysis results and the secondary ion mass spectrometry (SIMS) depth profiles of the silicon substrate. (C) 2003 Elsevier B.V. All rights reserved.