A method of fabricating a semiconductor device, the method including: forming a first mask pattern including a masking region and an open region on a substrate; forming a sacrificial layer to cover the substrate and the first mask pattern; patterning the sacrificial layer to form a seed layer and to expose the first mask pattern; forming a second mask pattern on the exposed first mask pattern; forming an epitaxial layer on the seed layer and the second mask pattern, and forming a void between the second mask pattern and the epitaxial layer; and separating the substrate from the epitaxial layer.