Development of a novel epitaxial-layer segmentation method for optoelectronic device fabrication

Describes the development of a new process for segmenting epitaxial-layer material and fabricating cleaved-cavity lasers. The technique, which involves growth substrate removal and use of a novel epitaxial-layer cleaving tool, is applicable to a variety of different materials and devices. IV-VI semiconductor epitaxial layers grown by molecular beam epitaxy on silicon [111] substrates with a water-soluble barium fluoride buffer layer were used. The layers were metallurgically bonded to the rectangular tips (500*1040 (mu)m) of copper bars held together by a small vise apparatus, the substrate was removed by dissolving the barium fluoride buffer layer in water, and the copper bars were separated by releasing the vise assembly. Current versus voltage characterization of separated p-n junction IV-VI epilayer structures on the tips of the copper bars showed nonlinear behavior with a forward bias current onset voltage ~250 mV, a value consistent with the room temperature bandgaps of the IV-VI alloys used. These results demonstrate the utility of this technique for obtaining epitaxial-layer structures with typical cleaved-cavity inplane laser dimensions.