Relationship between stress and dangling bond generation at the (111)Si/SiO2interface

Electron spin resonance analysis of the intrinsic density [${\mathit{P}}_{\mathit{b}}$] of interfacial ${\mathit{P}}_{\mathit{b}}$ (⋅Si≡${\mathrm{Si}}_3$) defects in thermal (111)Si/${\mathrm{SiO}}_2$ as a function of oxidation temperature ${\mathit{T}}_{\mathrm{ox}}$ in the range 200–1140°C reveals a close linear correlation with the average stress ${\mathrm{\sigma }}_{\mathrm{av}}$ in the superficial ${\mathrm{SiO}}_2$ layer. An almost constant high value [${\mathit{P}}_{\mathit{b}}$]∼1×${10}^{13}$ ${\mathrm{cm}}^{\mathrm{-}2}$ is found for ${\mathit{T}}_{\mathrm{ox}}$≤800 °C, while from this ${\mathit{T}}_{\mathrm{ox}}$ onward, [${\mathit{P}}_{\mathit{b}}$] decreases monotonically to <${10}^{10}$ ${\mathrm{cm}}^{\mathrm{-}2}$ along with ${\mathrm{\sigma }}_{\mathrm{av}}$→0 for ${\mathit{T}}_{\mathrm{ox}}$→1150 °C. The underlying effect is cooperative structural relaxation of the ${\mathrm{SiO}}_2$ layer initiating at ∼800 °C, thus gradually eliminating the need for ${\mathit{P}}_{\mathit{b}}$ formation to account for lattice mismatch.