The P_b Center at the Si-SiO₂ Precipitate Interfaces in Buried Oxide Materials: ²⁹Si Hyperfine Interactions and Linewidths

Abstract

Electron Spin Resonance (ESR) has recently been very successfully applied to the problem of thermal oxide — Si interfaces^1–3. That work resulted in the identification of the P_b center as the primary fast interface trap and the determination that its basic structure is a trivalent Si atom at the Si-SiO₂ interface. In addition to the technological motivations, there is also fundamental interest in this defect, which is at the interface between a crystalline solid and an amorphous one, and, therefore, might be expected to have features characteristic of defects in both types of materials. The detailed ESR study of the structure of this defect is inhibited by the small fraction of interfacial atoms in a typical Si-SiO₂ structure. It has recently been shown that the principal paramagnetic defect observed in silicon on insulator materials formed by oxygen implantation is a P_b center at the interface between Si and SiO₂ precipitates in the Si film over the buried oxide layer^4–6. The total precipitate surface area can be much greater than the simple surface area of an Si-SiO₂ structure. This increased number of “interfacial” atoms affords the opportunity to conduct more detailed ESR studies of the P_b center than readily possible with Si-thermal oxide structures. In addition these interfaces are formed in a significantly different manner than the thermal oxide interfaces and a comparison of the P_b centers formed in the two manners may offer insights into their formation.