Mg-doped AlGaN grown on an AlN/sapphire template by metalorganic chemical vapour deposition

The growth of high-performance Mg-doped p-type AlxGa1-xN (x = 0.35) layers using low-pressure metal-organic chemical vapour deposition on an AlN/sapphire template is reported. The influence of growth conditions on the p-type conductivity of the AlxGa1-xN (x = 0.35) alloy was investigated. It was found that the p-type resistivity of the AlGaN alloy demonstrates a marked dependence on the Mg concentration, V/III ratio and group III element flow rate. A minimum p-type resistivity of 3.5 Omega cm for Al1-xGa1-xN (x = 0.35) epilayers was achieved. A Ni/Au (10 nm/100 nm) ohmic contact was also fabricated and a specific contact resistivity of 8.1 X 10(-2) Omega cm(2) was measured. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.