The energy deposition for electron beams in Si-SiO2 materials has been calculated with the two-group theory of electron transportation. The absorption dose for 1.0MeV and 1.5MeV electrons in MOS capacitors was measured with an extrspolation ionization chamber which is equivalent to silicon in stopping power.The chemical structure

interface states and C-V curve of the MOS samples were analyzed before and after irradiation with X-ray photoelectron spectroscopy （XPS）

Auger electron spectroscopy （AES）

deep level transient spectroscopy （DLTS） and C-V method. According to the theory and experimental data

the relationship among election energy deposition

ionizing damage and radiation effect is derived from a view point of dosimetry. Finally

a preliminary explaination for the ionizing damage mechanisms is given.