h S T R A C TWe report the first ab initio quantum mechanical investigation of the structure of the E', center in amorphous SiOz (a-SiOz). Our calculations suggest that the unpaired electron is shared by only two Si atoms, irrespective of the Si cluster size.

No abstract

We have performed current-voltage, capacitancevoltage and electron-paramagnetic-resonance (EPR) characterization of silicon-on-insulator (SOI) samples, subjected to a wide variety of irradiation and anneal treatments. By comparing transport properties and interfacial reaction mechanisms, we provide evidence for an intrinsic difference in the response of mobile protons in these oxides, depending on whether they are generated by irradiation or by & annealing. A radiation effects study of SO1 buried oxides containing annealing induced mobile protons is presented to gain insight into the mechanisms behind these fundamental differences. Electrical characterization shows that, for these devices, the initial interface trap and mobile proton densities are largely unaffected by the irradiation. However, if the irradiation is carried out in the presence of positive bias applied to the top Si, the protons become trapped in shallow levels. These proton traps are activated by the irradiation and are located near the oxide/substrate interface. These results may lead to improved radiation hardness of buried oxides for nonvolatile memory and other applications.

The atomic structure and spin properties of two previously undescribed amorphous silicon dioxide fundamental point defects have been characterized for the first time by ab initio quantum mechanical calculations. Both defects are electrically neutral trivalent silicon centers in the oxide. One of the defects, the X-center, is determined to have an O,Si=SiT atomic structure. The other defect, called the Ycenter, is found to have an OSi,=SiT structure. Calculated electronic and electrical properties of the new defect centers are consistent with the published characteristics of the oxide switching trap or border trap precursors. center.

No abstract