Luminescent porous silicon prepared by reactive ion etching

Realization of luminescent porous silicon structures by a sequential reactive ion etching is reported. The process is composed of one etching and two passivation subsequences. The impact of substrate resistivity, plasma power and the duration of the etching subsequence on the porosity and thickness of the fabricated porous silicon layer are investigated, as are the roles of two passivation subsequences. The porous silicon layer shows stable photoluminescence in the blue portion of the spectrum. Luminescence stability is due to the stable passivating oxyfluoride layer formed in the two passivation subsequences. Formation of the stable passivating layer is due to the controlled oxidation of the porous silicon surface and the passivation of the dangling bonds in the fluorination subsequence. Since the fabrication process is performed at room temperature, it can be used as a post-fabrication treatment to integrate light-emitting structures with microelectronic circuits.