Abstract: A method for cutting a single crystal having a first polar axis includes the steps of arranging the single crystal relative to a cutting tool in such a way that the first polar axis is oriented perpendicular to an intended cutting plane; arranging at least one further single crystal having a second polar axis in such a way that the first and the second polar axis are oriented substantially parallel but opposite one another; and simultaneously guiding a cutting tool through the single crystal and the at least one further single crystal along the intended cutting plane.

Abstract: An object of the present invention is to provide, even when a single crystal of a material other than AlN is used as a crystal, an AlN bulk single crystal having fewer defects and high quality, a method for producing such an AlN bulk single crystal, and a semiconductor device. A feature is to select, as a surface 1a of a hexagonal single crystal substrate serving as a seed crystal 1, a plane inclined at an angle of 10° to 80° with respect to the C-plane (FIG. 1(a)), and to grow an AlN single crystal 2 as a growth plane 2a on the surface 1a by a sublimation method (FIG. 1(b)).