Structural Analysis of Silicon Nanostructures Obtained from Thermal Annealing of a-Si:H/SiO2 Superlattices

This paper reports the synthesis and characterization of silicon quantum dots (QDs) obtained by thermal annealing of hydrogenated amorphous silicon (a-Si:H)/silicon oxide (SiO2) supperlattices deposited by plasma-enhanced chemical vapour deposition (PE-CVD). The as-deposited supperlattices have been annealed in high-temperature vacuum chamber, at temperatures up to 1100 °C, where in-situ phase transformation was monitored by x-ray diffractometry, XRD. It is shown that onset of crystallization and phase separation occur at different annealing temperature depending on the a-Si:H sub-layer thickness. Complete crystallization of the films and precipitation of the QDs occur at 1000 °C.