The surface treatment with NH/sub 3/ for GaN grown by a sublimation technique

We have applied surface treatment with ammonia to laterally grown GaN. The technique of sublimation was used for the bulk growth of GaN at a temperature of 1080°C, with a reacting gas consisting of NH/sub 3/ and N/sub 2/, on a substrate of metalorganic chemical vapor deposited GaN film/sapphire. With the surface treatment, the laterally grown GaN appears to have an improved surface and structure: cracks are conspicuously reduced as observed with a UV-microscope and crystal uniformity is increased as shown by X-ray diffraction.