AN INVESTIGATION OF OXIDIZED POROUS SILICON BY INFRARED-SPECTROSCOPY

The oxidation of porous silicon has been studied mainly by optical spe ctrometry and AFM (Atomic Force Microscopy). The annealing behaviour o f the Si-H-2-, Si-H and Si-O-Si-related IR bands were investigated for the range 20-500 degrees C at atmospheric pressure. The study is devo ted to the process of hydrogen and oxygen competition during the porou s silicon oxidation. We found that at 200 degrees C at atmospheric pre ssure the lifetime of the Si-H-2 bond is about 4 min; for Si-H it is e stimated at 20 min. The increase in Si-O absorption at 1 100 cm(-1) in dicated an activation energy of 5.1 kcal mol(-1). UV-Vis spectrometry and AFM were used to obtain information about the topology of the poro us silicon surface. Comments on some links between the Si-O-Si band pr ofile and the geometry of the oxidised silicon skeleton are included. (C) 1997 Elsevier Science B.V.