Electron spin resonance observation of an interfacial GePb1-type defect in SiO2/(100)Si1−xGex/SiO2/Si heterostructures

Using electron spin resonance (ESR), we report on the observation of a first Ge dangling bond (DB)-type interface defect in the SiO(2)/(100)Ge(x)Si(1-x)/SiO(2)/(100)Si heterostructure manufactured by the condensation technique. The center, exhibiting monoclinic-I (C(2v)) symmetry with principal g values g(1) = 2.0338 ± 0.0003, g(2) = 2.0386 ± 0.0006, g(3) = 2.0054 is observed in maximum densities of ∼6.8 × 10(12) cm(-2) of the Ge(x)Si(1-x)/SiO(2) interface for x∼0.7, the signal disappearing for x outside the 0.45-0.93 range. The notable absence of interfering Si P(b)-type centers enables unequivocal spectral analysis. Collectively, the combination of all data leads to depicting the defect as a Ge P(b 1)-type center, i.e. not a trigonal basic Ge P(b(0))-type center ([Formula: see text]). Understanding the modalities of the defect's occurrence may provide an insight into the thus far elusive role of Ge DB defects at Ge/insulator interfaces, and widen our understanding of interfacial DB centers in general.