IMPROVED CAPPING LAYERS FOR SUPPRESSION OF AMBIENT AGING IN POROUS SILICON

Accelerator-based nuclear techniques were used to study the ageing of as-prepared and aluminium-capped porous silicon samples with a porosit y of 55% and with two different morphologies (microporous and mesoporo us). Aluminium surface capping layers with thicknesses in the range 0. 1-0.5 mu m were applied by rf sputtering. The uncapped microporous sam ples aged more rapidly in air than did mesoporous samples. The sputter ed capping layers were found to be effective for stabilizing porous si licon against atmospheric oxidation, irrespective of the thickness of the capping layer.