Studying evolution of the ensemble of micropores in a SiC/Si structure during its growth by the method of atom substitution

The time evolution of the ensemble of micropores formed in the near-surface region of silicon during the growth of thin films of silicon carbide is studied by the method of atom substitution. SiC/Si samples are studied by scanning electron microscopy, ellipsometry, and confocal Raman microscopy. The formation of the porous layer involves several characteristic stages: the emergence of single pores, their growth with the formation of dendrite-like structures, and subsequent coalescence into a continuous layer. It is shown that the thickness of the porous layer at the initial stages of the growth is proportional to the cubic root of time. The possible mechanisms of pore formation are discussed and a theoretical model is proposed to describe the dependence of the average thickness of the porous layer on time. The model is in a good qualitative agreement with the experimental results.