Abstract: Porous silicon (PS) samples were fabricated by pulse current etching using different times. The down-ward uniformity and optical properties of the PS layers have been investigated using reflectance spectroscopy, photo-luminescence spectroscopy, and scanning electron microscopy (SEM). The relationship between the refractive index and the optical thickness of PS samples and the etching depth has been analyzed in detail. As the etching depth increases, the average refractive index decreases, indicating that the porosity becomes higher, and the formation rate of the optical thickness decreases. Meanwhile, the reflectance spectra exhibit less intense interference oscillations, which mean the uniformity and interface smoothness of the PS layers become worse. In addition, the intensity of PL emission spectra is slightly increased.

Key words: porous silicon