Journal of Materials Science. Materials in Electronics vol:18 issue:7 pages:735-741
Electron spin resonance of paramagnetic point defects was used to probe (100)Si/LaAlO3 structures with nm-thick amorphous high-dielectric constant (kappa) LaAlO3 layers deposited directly on clean (100)Si by molecular beam deposition at similar to 100 degrees C. Unlike common high-kappa metal oxide/Si entities, no P-b-type interface defects could be observed in the as-grown state, revealing the absence of an Si/SiO2-type interface in terms of these archetypal Si-dangling bond-type Si/SiO2 interface defects (P-b0, P-b1). This state is found to persist during subsequent thermal treatment (5% O-2/N-2 mixture) up to T (an) similar to 800 degrees C, indicating a thermally stable abrupt Si/LaAlO3 interface. However, in the range T (an) similar to 800-860 degrees C, a Si/SiO2-type interface starts forming as evidenced by the appearance of P-b0 defects and, with some retardation in terms of T (an), the EX center-an SiO2 associated defect, attesting to significant structural/compositional adaptation. Monitoring the defect density versus T (an) indicates the SiO (x) nature of the interlayer to disintegrate again upon heating at T (an) >= 930 degrees C, possibly related to intensifying crystallization and silicate formation. Despite intensive search, no LaAlO3-specific point defects could be revealed.