Atomically smooth and homogeneously N-polar AlN film grown on silicon by alumination of Si3N4

By using an alumination process of Si3N4 at high temperature with aluminum flux irradiation for sufficient time, homogeneously N-polar and atomically smooth AlN film has been realized on silicon substrate with inversion domain suppressed to less than 3.0 × 106 cm−2 and root mean square surface roughness of ∼0.4 nm. A general interface model is proposed to explain the mechanism of polarity determination. The sharp AlN(0001)/Si(111) interface exhibits 5:4 coincidence domain matching, resulting in an almost fully relaxed AlN film.