OPTICAL EFFECTS OF BURIED CONDUCTIVE LAYERS FORMED BY MEV ION-IMPLANTATION

Phosphorus ions have been implanted into silicon at an incident energy of 1.5 MeV to a dose of 1.5 x 10(15) cm(-2) or 7.5 x 10(15) cm(-2). B uried conductive layers have been formed in the Si substrate after ann ealing at 1050 degrees C for 20 s. IR reflection spectra in the wavenu mber range 500-4000 cm(-1) were measured and interference fringes rela ted to free-carrier plasma effects were observed. By detailed theoreti cal analysis and computer simulation of IR reflection spectra, the dep th profile of the carrier concentration, the carrier mobility near max imum carrier concentration, and the carrier activation efficiency were obtained. The physical interpretation of the results and a critical d iscussion of the sensitivity of data fitted to variation in parameters are given.