Kinetics of oxygen diffusion to the grain boundary in oxygen-rich directionally cast silicon bicrystals

Abstract

Abstract The electron beam induced current mode of a scanning electron microscope has been used to measure the minority carrier recombination velocity at the depletion layer edge of the grain boundary as a function of annealing time (30 – 240 min) and temperature (600 – 900 °C) in oxygen-rich directionally cast silicon bicrystals. The minority carrier recombination velocity at the grain boundary has been found to increase significantly with increasing annealing time and temperature. The grain boundary barrier potential has been determined from the zero-bias capacitance as a function of annealing time and temperature. A theoretical model has been proposed whereby the diffusivity of oxygen in silicon can be computed from the increase in grain boundary interface trap density, calculated from the grain boundary recombination velocity and barrier potential. The diffusitity D ( cm 2 s −1 ) of oxygen in silicon was found to be D=0.27exp -2.56eV kT in the temperature range 600 – 900 °C.