Influence of Deposition Temperature on the Si Richness in SiC-Based Thin Films for Optoelectronic Applications

Abstract

Silicon nanoclusters/nanocrystals (Si-NC) embedded in silicon carbide (SiC) host matrix is a promising alternative to high bandgap dielectric matrices for solar cell application. However, the formation of Si-NC is a challenge since silicon carbide nanoclusters (SiC-NC) are formed with greater ease in the SiC host matrix. In this context, this work focuses on analyzing the influence of process parameters (deposition and annealing temperature) to synthesize the silicon-rich SiC film (a-SixCy) for favoring Si-NC formation in the host matrix. In this paper, the Si-NC in a-SixCy is obtained by co-sputtering of SiC and Si targets at different deposition temperatures (Td) such as room temperatures 200 °C, 350 °C, and 500 °C. It is annealed at various temperatures and ambience such as vacuum (VA) and conventional thermal annealing (CTA). The structural and optical properties are investigated using spectroscopic ellipsometry, Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and photoluminescence spectroscopy (PL). The refractive index varies between 3.3 and 3.7 which indicates the Si richness in the film. In FTIR absorption spectra and Raman spectra, change in intensity and position of Si-related vibrations varies depending on the excess Si incorporation. PL spectra show emission in the range of 412–440 nm that varies with different annealing and confirms the possibility of the Si-NC formation in the film.