Remote oxygen-containing hydrogen plasma treatment of porous silicon

Abstract

The effects of treatment with remote oxygen-containing hydrogen plasma on electrochemically etched porous silicon have been studied. X-ray photoelectron spectroscopy, infrared, and elastic recoil detection measurements showed the nonuniform incorporation of oxygen in the porous silicon layer. The amount of nitrogen increased while the carbon concentration dropped in the oxidized layer. The photoluminiscence (PL) intensity of plasma-treated films increased by up to a factor of approximately 70 compared to as-prepared samples, while the peak position was red shifted. The PL enhancement seems to be correlated with an O/Si ratio near 1.5. After treatment, bright PL was observed from a partially oxidized layer, covered by a SiO2 layer which could be several nm thick.