Thermal post-oxidation interface degradation in (111) Si/Si${\mathrm{O}}_2$ has been isolated by electron-spin resonance (ESR) as a permanent $P_b$ (Si ≡ ${\mathrm{Si}}_3$) interface defect creation. This process, initiating from ∼640 °C onward, reveals interface breakdown on an atomic scale as interfacial SiO bond rupture. The crucial creation step has been isolated as thermal cycling in an O-free ambient. Once created, the new $P_b$ system exhibits similar fully reversible H passivation-depassivation kinetics as the preexisting one, naturally introduced during oxidation. ESR is herewith raised to a powerful probe for Si/Si${\mathrm{O}}_2$ degradation.

• Received 3 June 1996

DOI:https://doi.org/10.1103/PhysRevB.54.R11129