Embodiments regard micro-size devices formed by etch of sacrificial epitaxial layers. An embodiment of a method includes forming a plurality of epitaxial layers on a sapphire crystal, wherein the epitaxial layers include a buffer layer on the sapphire crystal, a sacrificial layer above the buffer layer, and one or more device layers above the sacrificial layer; etching to singulate the semiconductor devices, the etching being through the one or more device layers and wholly or partially through the sacrificial layer; electrochemical etching of the sacrificial layer; and lift-off of one or more semiconductor devices from the buffer layer.