Laser slicing of a diamond at the {100} plane using an irradiation sequence that restricts crack propagation along the {111} plane

Laser slicing is a technique of slicing materials along cracks formed by scanning a focused ultrashort-pulse laser beam inside the materials. In this paper, we propose a novel slicing technique to fabricate diamond wafers and demonstrate slicing at the {100} surface. Cracks parallel to the {100} plane are needed to fabricate the wafer. However, crystal materials, including diamond, contain a cleavage plane at the {111} plane, which cracks easily. Typically, cracks propagate not only along the {100} plane, which is the intended slicing plane, but also along the {111} plane, which increases the kerf loss. To restrict these undesirable cracks, we devised a laser irradiation sequence and developed a cutting method that restricts cracking along the {111} plane. This slicing technology will potentially pave the way toward the realization of diamond semiconductors based on diamond wafers with {100} surfaces.