Growth of thick AlxGa1−xN ternary alloy by hydride vapor-phase epitaxy

Growth of thick AlxGa1−xN ternary alloy using AlCl3 and GaCl gases as group III precursors was performed by hydride vapor-phase epitaxy (HVPE). C-axis-oriented AlGaN layers could be grown at 1100 °C. It was found that the growth of AlxGa1−xN by HVPE was affected by the presence of H2 in the carrier gas. Therefore, the solid composition x in AlxGa1−xN ternary alloy could be controlled by changing the input Al mole ratio of the group III precursor (RAl) and/or the low range (<10%) of partial pressure of hydrogen (H2) in the carrier gas (Fo). The growth rate of approximately 30 μm/h was obtained under inert carrier gas (Fo=0.0), while the growth rate decreased rapidly in the low RAl under a low partial pressure of H2 in the carrier gas (Fo=0.1). These results are in good agreement with the thermodynamic prospect. Thus, the growth of AlxGa1−xN using HVPE is thermodynamically controlled.