Radiation-Induced Paramagnetic Defects in MOS Structures

We have subjected thermally grown films of SiO2 on Si substrates to Co60 gamma irradiation. Using electron spin resonance we observe three radiation-induced paramagnetic defect centers in the structures at room temperature. One resonance appears to be unambiguously associated with trivalent silicon bonded to three other silicons at the Si/SiO2 interface. Two other resonances are very much like resonances observed earlier in irradiated high purity bulk SiO2; those bulk SiO2 resonances have been associated with trivalent silicons bonded to three oxygens and unpaired electrons in nonbonding oxygen 2p orbitals.