Growth of thick Al xGa 1−xN ternary alloy by hydride vapor-phase epitaxy

Abstract

Growth of thick Al x Ga 1− x N ternary alloy using AlCl 3 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 Al x Ga 1− x N by HVPE was affected by the presence of H 2 in the carrier gas. Therefore, the solid composition x in Al x Ga 1− x N ternary alloy could be controlled by changing the input Al mole ratio of the group III precursor ( R Al) and/or the low range (<10%) of partial pressure of hydrogen (H 2) in the carrier gas ( F o). The growth rate of approximately 30 μm/h was obtained under inert carrier gas ( F o=0.0), while the growth rate decreased rapidly in the low R Al under a low partial pressure of H 2 in the carrier gas ( F o=0.1). These results are in good agreement with the thermodynamic prospect. Thus, the growth of Al x Ga 1− x N using HVPE is thermodynamically controlled.