Fe Ions Diffusion and Oxygen Complexes Evolution duringThermodonors Annealing in B-Doped Czochralsky Silicon Crystal

摘要

The great enhancement of the minority carrier recombination rate after optical activationof FeB pairs was used for investigation of interstitial Fe ions diffusion in p-type Czochralsky siliconby Surface Photo-Voltage Technique (SPV). Highly reproducible profiles of the Fe ions distributionwere obtained after one-time thermodonors annealing process (650 °C, 30 min.) with Fe filmevaporated on one side of silicon slab and successive layer by layer silicon slab etching. Evolutionof Fe concentration distribution between both sides of initially inhomogeneously contaminatedsilicon slab in durable annealing processes was investigated. Gradual Fe concentration reductionnear preliminary contaminated slab surface and Fe concentration increase near opposite surfacewere observed. Fe concentrations near both surfaces become equal after approximately 10-timesannealing in agreement with diffusion rate obtained by the first method. Chaotic release and hidingof latent Fe were observed after 5-7 hours of annealing process. Two-exponential increase of otherthan Fe recombination centers concentration was observed during 650 °C annealing. Bothexponential factors are found to be functions of interstitial oxygen concentration in the siliconingot.