Improvement of Crystalline Quality of SOS with Laser Irradiation Techniques

The crystalline quality of silicon layers grown on sapphire substrates by vapor-phase epitaxial growth is improved by exposing the layers to multiple doses of laser irradiation of a suitable energy density. SOS wafers have been irradiated with 25 ns pulses from a Q-switched ruby laser. The samples have been analyzed by Hall mobility, defect density and channeling. The electron Hall mobilities of samples exposed 2–4 times at an energy density of 1.5 J/cm2 are twice those of as-grown SOS. Under the same conditions, etch pit density and stacking fault density decreased by a factor of 3–4 and 10, respectively.