Gas source molecular beam epitaxy of high quality AlxGa1−xN (0⩽x⩽1) on Si(111)

Layers of AlxGa1−xN, with 0⩽x⩽1, were grown on Si(111) substrates by gas source molecular beam epitaxy with ammonia. We show that the initial formation of the Si–N–Al interlayer between the Si substrate and the AlN layer, at a growth temperature of 1130–1190 K, results in very rapid transition to two-dimensional growth mode of AlN. The transition is essential for subsequent growth of high quality GaN, AlxGa1−xN, and AlGaN/GaN superlattices. The undoped GaN layers have a background electron concentration of (2–3)×1016 cm−3 and mobility up to (800±100) cm2/V s, for film thickness ∼2 μm. The lowest electron concentration in AlxGa1−xN, with 0.2