Study on Mechanical Cleavage Mechanism of GaAs via Anisotropic Stress Field and Experiments

To satisfy the increasing requirements for high-quality cavity mirrors for semiconductor lasers, the influence of the anisotropic stress field generated by scratching GaAs on the quality of cleavage planes was investigated. First, a novel method for calculating the interplanar spacing was proposed to estimate the favourable direction for the scratching operation. Some mechanical properties in the scratching direction were calculated. Consequently, an anisotropic calculation model of the stress field generated by scratching was established. The calculation model was used to analyse the y-component stress field distribution along different directions beneath the indenter. The results show that the maximum stress occurs at the contact area between the material and indenter tip, and the stress along the <100> orientation is lower than that along the <110> orientation. According to our experiments, a significant decrease in the average radial crack length and a slight decrease in the average kerf width were observed along the [011] direction compared to the corresponding results for the [001] direction. In addition, the (011) plane had a surface roughness of 0.43 nm and could become a preferential cleavage plane under a low scratching load. The results of this study contribute to advance our understanding of the mechanisms of mechanical cleavage processes.