EFFECT OF RESISTIVITY AND CURRENT-DENSITY ON PHOTOLUMINESCENCE IN POROUS SILICON PRODUCED AT LOW HF CONCENTRATION

An experimental study of the intensity of photoluminescence (PL) of po rous silicon prepared from an anodic dissolution of Si at low HF conce ntration (12.5%) of p-type (100) 0.01, 1 and 10 Ohm cm substrates as a function of substrate resistivity and etching current density has bee n performed. Based on the experimental results a photoluminescence eff iciency diagram is proposed. Etching of p(+)-type silicon samples with out light illumination produces PSi layers whose PL spectra show inter ference fringes. Comparison of the fringes in PL and in light reflecti vity demonstrates unambiguously that they originate from the interfere nce of the light reflected at the PSi/ bulk Si interface and depend on the thickness of the PSi layer. The intensity and frequency of the in terference fringes are found to be strongly dependent on the anodizati on current. Implications of PSi layer fabrication at low HF concentrat ion are discussed. (C) 1998 American Institute of Physics. [S0021-8979 (98)06623- 7].