The electron trapping behavior of SiO2has been measured as a function of thickness at 295 and 77 °K. The devices used were metal‐oxide‐semiconductor devices with the SiO2grown thermally. The results indicate bulk traps are dominant at 295 °K and traps associated with the Si‐SiO2interface are dominant at 77 °K. The effect of processing conditions was also studied and the optimum conditions are different for the two temperatures used for the measurements. These observations have been verified using a photoI‐Vtechnique. The generation of donor states in the SiO2near the Si‐SiO2interface was observed as a result of the electron current through the SiO2.