Exploring the potential of the fabrication of large-size mirror facet for semiconductor laser bar utilizing mechanical cleavage

While mechanical cleavage technology is an ideal alternative approach to fabricate large-size mirror facets for high-power laser bar, there has been little scientific understanding of mechanical cleavage mechanisms. To fill this gap, cleavage experiments were designed according to the Taguchi method for analyzing the main effects of three parameters. Surface and subsurface cracks and cleavage plane morphology are analyzed as well. The results show that scribing load has significant impact on the scratch morphology as compared with other parameters, and quadratic polynomial models are formulated to predict kerf width and maximum damage width values. For scribing along the [0−1−1] direction on the (100) GaAs wafer, the subsurface cracks are TLC and LC which propagate along [0-11] direction and MC which propagates along [100] direction. The achieved optimal combination of parameters are scribing load of 10 g, scribing speed of 20 mm/s and scribing length of 0.6 mm. The undamaged length of cleaved planes can reach 11.77 mm. Our results demonstrate that mechanical cleavage is a powerful technique which could guide actual production and manufacturing field of high-power GaAs-based laser bars.