Moskal D. Defect formation in subsurface layers of GaAs single crystals influenced with low-level spatially-modulated laser irradiation.

Object of researches: GaAs semi-conductor single-crystals brand AGChT-1-25а-1. Purpose of work: establishment of physical laws of defect formation in sub-surface layers of GaAs single-crystals influenced with spatial modulated by intensity low-level laser irradiation. Methods: irradiation of GaAs crystals in under-threshold conditions by pulses of laser radiation with Gaussian and diffraction distribution of intensity, metallographic researches, АFМ and REМ. Numerical methods of differentiation and integration. Results. Novelty: method of structural modification of GaAs single-crystal sub-surface layers is offered. Fields of temperatures, deformations and thermal stresses created in sub-surface GaAs layer are computed numerically. The value of limit energy density irradiation of GaAs with millisecond laser pulse, below which point defects are formed without activation of dislocation sliding and crack formation processes, is established. The opportunity of creation low-dimension cluster structures in GaAs sub-surface layer under influence of millisecond and nanosecond laser pulses with lateral-periodic distribution of intensity is shown. Mechanism of diffusion-deformation redistribution of own point defects in GaAs under action of the diffraction-modulated laser irradiation is offered.