Electrically detected magnetic resonance and near-zero field magnetoresistance in 28Si/28SiO2

We report on electrically detected magnetic resonance (EDMR) and near-zero-field magnetoresistance (NZFMR) measurements observed through spin-dependent trap-assisted-tunneling on unpassivated Si/SiO2 metal–insulator–semiconductor capacitors comparing those containing silicon of natural isotopic abundance and silicon depleted of 29Si. Although our measurements involve monitoring the spin-dependence of the trap-assisted-tunneling current responsible for leakage across the oxide, the EDMR spectra resemble that of a combination of Pb0 and Pb1 silicon dangling bonds sites at the Si/SiO2 interface. Additionally, we observe a substantial narrowing of the NZFMR response with the removal of 29Si nuclei. The breadth of the NZFMR response is strongly influenced by hyperfine interactions. Since superhyerfine interactions between 29Si nuclei and silicon dangling bonds at the Si/SiO2 interface are a full order of magnitude stronger than such interactions involving silicon dangling bonds defects (E′ centers) within the oxide, the NZFMR results also strongly suggest a response dominated by Si/SiO2 interface trap defects. These results collectively suggest very strongly that the leakage currents that we observe involve tunneling from Si/SiO2 Pb dangling bonds to defects within the oxide. Our results thus offer fundamental insight into technologically important phenomena involving oxide leakage currents in metal–oxide–semiconductor devices such as stress induced leakage currents and time dependent dielectric breakdown.