The present invention provides a method of fabricating a semiconductor substrate and a method of fabricating a light emitting device. The method includes forming a first semiconductor layer on a substrate, forming a metallic material layer on the first semiconductor layer, forming a second semiconductor layer on the first semiconductor layer and the metallic material layer, wherein a void is formed in a first portion of the first semiconductor layer under the metallic material layer during formation of the second semiconductor layer, and separating the substrate from the second semiconductor layer by etching at least a second portion of the first semiconductor layer using a chemical solution.