Development of a low-temperature GaN chemical vapor deposition process based on a single molecular source H2GaN3

We report the development of a simple and highly efficient chemical approach to growing GaN thin films between 150 and 700 degrees C using a single molecular source, H2GaN3. Uncommonly low-temperature growth of nanocrystalline GaN films with a wurtzite structure is readily achieved at 150-200 degrees C from the thermodynamically driven decomposition of the precursor via complete elimination of the stable and relatively benign H-2 and N-2 by-products. Highly oriented columnar growth of crystalline material is obtained on Si at 350-700 degrees C and heteroepitaxial growth on sapphire at 650 degrees C. Crucial advantages of this precursor include: significant vapor pressure which permits rapid mass transport at 22 degrees C; and the facile decomposition pathway of stoichiometric elimination of H-2 and N-2 over a wide temperature and pressure range which allows film growth at very low temperatures and pressures (10(-4)-10(-8) Torr) with growth rates up to 80 nm per minute. (C) 1999 American Institute of Physics. [S0003-6951(99)00306-X].