Preparation and photoluminescence of SiC/Si/SiO2 multi-layer structure

A multi-layer structure of SiC/Si/SiO2 was fabricated by successive deposition of SiC and Si using plasma-enhanced chemical vapor deposition and post-deposition thermal oxidation of the part as-deposited Si surface layer. The samples oxidized at 900 °C for various annealing times exhibit two strong photoluminescence peaks in the blue-light range, one is a stable PL peak at 433 nm and the other is an unstable PL peak at a range of 445–460 nm. A maximum PL intensity was obtained when oxidation time is 40 min over this oxidation time, the PL intensity decrease up to disappear with the increase of the oxidation time. Origin of the PL was discussed and a tight-binding theoretic calculation was used to study the relation of the excess Si defect and PL properties. Results show that the two PL peaks observed may be attributed to excess Si defect centers and SiC nanocrystalline with different size in SiC/Si/SiO2 multi-layer structure.