The E1 and E2structures in the optical constants of silicon have been profusely used during the last 20 years for studying the electronic states (band structure) of this semiconductor. We have measured these structures in bulk and ion implanted laser annealed n- and p-type silicon as a function of carrier concentration. The measurements were performed with an automatic rotating analyser ellipsometer in the range 2-6 eV. The structures red-shift and broaden with increasing carrier concentration, but independently of type. The laser annealed samples yield results which join smoothly with those for the bulk samples. They enable us to reach doping levels much higher than those for bulk samples.
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