NOVELTY - The device has a substrate e.g. gallium arsenide (GaAs) substrate, comprising epitaxial structures (40) on sides of the substrate, where one of the sides is on an opposite side of the substrate from the other side. The structures comprise an etch stop, an epitaxial layer e.g. GaAs epitaxial layer (58), and a carrier medium (72). The etch stop and the layer are grown on the former side of the substrate after which the substrate is flipped, and another etch stop and the layer are grown on the opposite side of the substrate. The medium is added to the layer on the sides.    USE - Semiconductor device.    ADVANTAGE - The device employs bifacial epitaxial growth, where a bottom and a top of the substrate is processed into separate structures, and notion is to grow structures on one side of the substrate and grow similar structures on the opposite side of the substrate by stopping the growth after one of the structures completes process for flipping the substrate and carrying out the growth of another structure on the opposite side of the substrate, so that the structures can be grown on a single common substrate, thus reducing a number of substrates required for fabrication process by a factor of two, admitting a simple and direct removal of the substrate, eliminating a need to require singulation before separation from the substrate using a number of different carriers including metals and performing the fabrication process in a compatible manner, and hence reducing damage of the substrate or reusing the substrate in a cost effective manner.    DETAILED DESCRIPTION - The carrier medium comprises silicon, metal, glass, gold, silver, copper, nickel, titanium and platinum. The epitaxial structures comprise laser cells, LED cells, infrared sensor cells, inverted metamorphic structures and solar cells. An INDEPENDENT CLAIM is also included for a method for fabricating epitaxial structures.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of an epitaxial structure.    Epitaxial structures (40)    Indium gallium phosphide epitaxial layers (56, 60)    GaAs epitaxial layer (58)    Carrier medium (72)