Optical Probing of Free-Carrier Plasma Effects of MeV IonImplanted Silicon

Boron ions have been implanted into silicon at an incident energy of 3 MeV to a dose of 5 x 10¹⁵ cm^-2. Buried conductive layers have been formed in the silicon substrate after annealing at 1050°C for 20s. Infrared (IR) reflection spectrain the wavenumber range of 500-4000cm^-1 have been measured and interference fringes related to free-carrier plasma effects observed. By detailed theoretical analysis and computer simulation of the IR reflection spectra, the depth profile of the carrier concentration, the carrier mobility near maximum carrier concentration, and the carrier activation efficiency have been obtained. The physical interpretation of the results was given.