Effect of tungsten coating on the relaxation time of photoconductivity in annealed Czochralski-Grown Si

The effect of tungsten coating on the degradation of the relaxation time of photoconductivity in Czochralski Si upon annealing was studied. It was found that the concentration of process-induced defects in tungsten-coated Si annealed at 800 and 900°C exceeded that in uncoated samples. Moreover, the annealed tungsten-coated samples showed stronger temperature dependences of the electron capture cross section of these defects, which suggests that the defects produced in these samples differ from those in uncoated Si. No additional recombination channels were found in the tungsten-coated sample annealed at 1000°C as compared to the uncoated samples. The resistivity and conductivity type of tungsten-coated Si remained unchanged upon annealing.