A comparative analysis on process dependent structural and optical properties of si-rich silicon carbide thin films

Abstract

Si nanoclusters (Si-nc) embedded in Silicon Carbide (SiC) matrix are promising for optoelectronic applications. Despite high temperature post fabrication treatments, it is often noticed that the formation of SiC-nc and amorphous-Si nanoclusters (a-Si nc) are favoured than Si nanocrystals. This paper carries out meticulous investigation on the variations in structural and optical properties of amorphous-Silicon rich Silicon carbide (a-SixCy) thin films with varying process conditions in deposition approach, deposition temperatures (Td) and post deposition annealing conditions. The films deposited by magnetron sputtering and co-sputtering techniques are subjected to various annealing temperatures (Ta) using conventional thermal annealing (CTA), rapid thermal annealing (RTA), vacuum annealing (VA) and in-situ (IA) annealing techniques. A comparative study with deposition and post-deposition conditions considering the effect of excess Si incorporation and the unintentional oxidation during various stages of sample preparation is reported. It is noticed that though Si-nc formed are predominantly amorphous, the films deposited at Td of 200oC and in-situ annealed are promising as they show a higher absorption coefficient (α) and refractive index in comparison with the other high temperature annealing approaches. Such a result paves way to analyse the possibility of these films for future optoelectronic applications at reduced thermal budget.