Thermal stress damage mechanism in single-crystal germanium caused by 1080 nm laser irradiation

Abstract

The process of thermal stress damage during 1080 nm laser ablation of single-crystal germanium was recorded in real time using a high-speed charge-coupled device. A three-dimensional finite element numerical model based on Fourier’s heat conduction equation, Hooke’s law and the Alexander–Hasson equation was developed to analyze the thermal stress damage mechanism involved. The damage morphology of the ablated samples was observed using an optical microscope. The results show that the cooling process has an important influence on fracture in the laser-irradiated region of single-crystal germanium. Fracture is the result of a combination of thermal stress and reduction in local yield strength.