Crack-free gallium nitride coating production involves using a buffer layer between the substrate and the coating, and inserting into the coating a monocrystalline layer whose crystal lattice parameter is less than that of the coating

摘要

Crack-free monocrystalline coating of gallium nitride or a mixed nitride of gallium and another metal on a substrate likely to cause extensive stresses in the coating is obtained by using a buffer layer between substrate and coating, and inserting a monocrystalline layer of a material of thickness 100-300 nm, preferably 200-250 nm, and whose crystal lattice parameter is less than that of gallium nitride or mixed nitride in the coating. Preferred Features: The thickness of the coating is at least 2 microns, preferably 2-5 microns. The mixed nitride comprises gallium aluminum nitride or gallium indium nitride. The substrate is silicon or silicon carbide. The buffer layer is aluminum nitride (AlN). The monocrystalline layer is AlN or aluminum gallium nitride (AlGaN). The gallium nitride or mixed nitride coating can include 1-5 monocrystalline layers of Al or AlGaN. Independent claims are given for: (A) a method for production of the coating; and (B) an electronic or optoelectronic device containing at least one of the invented coatings. Production of the of the coating comprises (a) optionally exposing the surface of the heated substrate to ammonia; (b) deposition of an atomic monolayer of aluminum; (c) deposition of the buffer layer; (d) growing a layer of GaN or a mixed nitride of Ga and another metal; (e) interrupting the previous stage (d); (f) growing the monocrystalline layer at 800-1000 degrees C, preferably 900-950 degrees C; (g) optionally repeating stages (d) to (f) up to 1-5 times; (h) continuing the growth of the layer of GaN or mixed nitride of Ga and another metal to a desired thickness; and (i) cooling the substrate and the coating. Deposition of the buffer layer and growth or deposition of the inserted monocrystalline layer are carried out by molecular beam epitaxy (MBE), metal-organic chemical vapor deposition (MOCVD), or hydride vapor phase epitaxy (HVPE).