Preparation of Si-quantumdots in SiC: single layer vs multi layer approach

In this paper the preparation of Si nanocrystals within a SiC matrix using two different methods, namely a single layer and a multi layer approach is investigated. For the preparation of the single and multi layers PECVD was used. Subsequently after deposition a thermal annealing at various temperatures up to 1100°C was performed. The influence of the thermal annealing on the optical and structural properties of the single and multi layers is analysed in detail. For both layer systems the crystallization of Si and SiC was observed by GIXRD and diffraction contrast bright field and dark-field TEM imaging. As a general trend, Si crystallizes at lower temperatures than SiC. When the annealing temperature is raised the Si- C bond density increases drastically. This is shown by FTIR spectroscopy. The SiC single layer annealed at 1100°C showed a strong PL signal centred at 1.8 eV. After a remote H passivation process the PL peak is absent.