A microelectronic assembly in which a semiconductor device structure is directionally positioned on an off-axis substrate (201). In an illustrative implementation, a laser diode is oriented on a GaN substrate (201) wherein the GaN substrate includes a GaN (0001) surface off-cut from the direction predominantly towards either the or the family of directions. For a off-cut substrate, a laser diode cavity (207) may be oriented along the direction parallel to lattice surface steps (202) of the substrate (201) in order to have a cleaved laser facet that is orthogonal to the surface lattice steps. For off-cut substrate, the laser diode cavity may be oriented along the direction orthogonal to lattice surface steps (207) of the substrate (201) in order to provide a cleave laser facet that is aligned with the surface lattice steps.