Thermally induced degradation of condensation-grown (100)Ge0.75Si0.25/SiO2 interfaces revealed by electron spin resonance

The thermal stability under isochronal annealing of the GeSi/SiO2 interfaces in the condensation grown silicon-germanium-on-insulator (100)Si/SiO2/Ge0.75S0.25/SiO2 structure has been assessed by electron spin resonance in terms of occurring interface defects. As to annealing in vacuum, this reveals thermal post-growth interface degradation, from ∼440 °C onward, on atomic scale as substantial generation of Ge dangling bond (GePb1) interface defects, previously identified as detrimental electron traps. A similar behavior is observed for annealing in H2 (∼1 atm), except that the interface degradation evolves more gradually. The data bear out that the temperature of technological H2 passivation treatments should not exceed ∼440 °C.