p-n junction formed in structures with macro-porous silicon

Boron doped glasses, obtained from organic solution under low temperature and deposited by spin-on technique, were used to form a highly doped p(+)-n junction into structures with macro-porous silicon (PS) layer of 0.4-6 mu m thickness. The junction was found to lie about 2.5 mu m deeper than the bottom of the pores, and almost independent on their thickness. Enhanced boron diffusion was explained by a presence of local electric fields, caused by tensions present at the border between PS layer and crystalline substrate. Reflectivity values of less than 10% were obtained over 450-1050 nm wavelength range for samples with PS layer, confirming the light-trapping effect in electrochemically etched structures. (C) 2000 Elsevier Science B.V. All rights reserved.