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°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°C from the thermodynamically driven decomposition of the precursor via complete elimination of the stable and relatively benign H₂ and N₂ by-products. Highly oriented columnar growth of crystalline material is obtained on Si at 350-700°C and heteroepitaxial growth on sapphire at 650°C. Crucial advantages of this precursor include: significant vapor pressure which permits rapid mass transport at 22°C; and the facile decomposition pathway of stoichiometric elimination of H₂ and N₂ 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.