Generation mechanisms of paramagnetic centers by gamma-ray irradiation at and near the Si/SiO2 interface

Abstract

P_b (⋅Si≡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.