GENERATION MECHANISMS OF PARAMAGNETIC CENTERS BY GAMMA-RAY IRRADIATION AT AND NEAR THE SI/SIO2 INTERFACE

P(b) (.S=Si3) and E' (.Si=O3) centers in the Si/SiO2 structure under gamma-ray radiation are studied with the electron-spin-resonance technique. The Si/SiO2 structures of (111), (110), and (100) planes are obtained using three different oxidation methods to control the concentration of the hydrogen-related impurities. It is first observed that the concentration of P(b) centers is decreased with increasing radiation dosage in samples with lower concentrations of impurities; the concentration dramatically increases in the samples with a higher concentration of impurities. The concentration of E' centers also increases with accumulated dosage. When the Si/SiO2 structure is fabricated under different oxidation temperatures, the saturated concentrations of P(b) centers after irradiation depend upon the oxidation temperature. The concentration of E' centers increases with oxidation temperature after irradiation. When the Si/SiO2 structure is fabricated under different cooling rates, concentrations of the P(b) centers are saturated after irradiation. The concentration of E' centers increases with increasing cooling rate.