Surface reconstruction of silicon and polysilicon by Nd:YAG laser etching: SEM, Raman and PL studies

A comparative study of porous silicon (PS) fabricated by laser-induced etching on n-type crystalline-silicon and n-type polysilicon substrates is presented here under near resonance conditions by employing a Nd:YAG laser. A scanning electron microscopic study of the two PS samples, prepared under identical processing conditions, elucidates differences in surface morphology. An analysis of the Raman and PL spectra from the two PS materials, employing quantum confinement models, is presented and it further elucidates differences in the nanocrystallites size distributions. A qualitative explanation for the differences is presented.