Influence of the N/Al Ratio in the Gas Phase on the Growth of AlN by High Temperature Chemical Vapor Deposition (HTCVD)
In order to achieve AlN bulk growth, HTCVD chlorinated process is investigated. High growth rate and high crystalline quality are targeted for AlN films grown on (0001) 4H SiC at 1750°C. The precursors used are ammonia NH3 and aluminium chlorides AlClx species formed in situ by action of Cl2 on high purity Al wire. Influences of N/Al ratio in the gas phase on growth rate, crystalline state and microstructure are presented. Growth rates of up to 200 µm/h have been reached for polycrystalline layers. Thermodynamic calculations were carried out and correlated to the experimental results. As-grown AlN layers were characterized by SEM and X-ray Diffraction. Surface morphology is studied by SEM and FEG-SEM and crystallographic orientations were obtained by X-ray diffraction on θ/2θ.
Amador Pérez-Tomás, Philippe Godignon, Miquel Vellvehí and Pierre Brosselard
A. Claudel et al., "Influence of the N/Al Ratio in the Gas Phase on the Growth of AlN by High Temperature Chemical Vapor Deposition (HTCVD)", Materials Science Forum, Vols. 615-617, pp. 987-990, 2009