Digitally alloyed modulated precursor flow epitaxial growth of Al_xGa_(1-x)N layers with A1N and Al_yGa_(1-y)N monolayers

摘要

We propose a new growth scheme of digitally alloyed modulated precursor flow epitaxial growth (DA-MPEG) using metalorganic and hydride precursors for the growth of Al_xGa_(1-x)N layers with high-Al content at relatively low temperatures. The growth of high-quality, high-Al content Al_xGa_(1-x) layers (x_(Al) > 50%) that are composed of A1N and Al_yGa_(1-y)N monolayers on AIN/sapphire template/substrates by DA-MPEG was demonstrated. The overall composition of the ternary Al_xGa_(1-x)N material by DA-MPEG can be controlled continuously by adjusting the Column III mole fraction of the atomic Al_yGa_(1-y)N sublayer. X-ray diffraction and optical transmittance results show that the AlGaN materials have good crystalline quality. The surface morphology of DA-MPEG AlGaN samples measured by atomic force microscopy are comparable to high-temperature-grown AlGaN and are free from surface features such as nano-pits.