Electron-spin-resonance study of radiation-induced paramagnetic defects in oxides grown on (100) silicon substrates

We have used electron-spin resonance to investigate radiation-induced point defects in Si/SiO2 structures with (100) silicon substrates. We find that the radiation-induced point defects are quite similar to defects generated in Si/SiO2 structures grown on (111) silicon substrates. In both cases, an oxygen-deficient silicon center, the E′ defect, appears to be responsible for trapped positive charge. In both cases trivalent silicon (Pb centers) defects are primarily responsible for radiation-induced interface states. In earlier electron-spin-resonance studies of unirradiated (100) substrate capacitors two types of Pb centers were observed; in oxides prepared in three different ways only one of these centers, the Pb0 defect, is generated in large numbers by ionizing radiation.