Abstract: A method and apparatus is described wherein a buried double heterostructure laser device is formed utilizing epitaxial layers of quaternary III-V alloys of gallium indium arsenide phosphide and wherein the buried layer is formed by first etching the p-type top layer of the structure down to the quaternary active layer forming a mesa. A second etchant is then provided which preferentially etches the active layer. This etchant is used to undercut the top layer by removing the active layer on both sides of the top mesa surface providing a narrow strip of active layer underneath the undercut mesa. The undercut is then filled in by a heat treatment process which results in migration or transport of the binary top layer and binary bottom layer to fill in the undercut, leaving the active layer buried in the binary material. In an alternate embodiment of the invention, the two-step etching process plus the transport phenomena is utilized to form the mirror surface of a laser device.