Stress induced leakage current (SILO) has been discussed for a long time by many researchers. The oxide traps are believed to be the cause of SILO but characterization of these traps is still not clear. In this paper, we demonstrate that the SILO related oxide traps can be distinguished into two kinds with different characterization parameter by PDO method. Linear fitting also shows that double oxide trap model is better than single oxide trap model. (C) 2004 Published by Elsevier Ltd.