Aluminum and aluminum nitride formation in sapphire by ion beam synthesis

Abstract

Abstract The ion beam synthesis of Al layers in c-plane sapphire by a single high-dose, high-temperature Al implantation step is studied using various methods. At sufficiently high doses, buried single-crystalline Al layers are obtained. XRD pole-figure measurements and transmission electron diffraction reveal an epitaxial relationship with the sapphire matrix according to [1 1 0] Al ‖[1 1 0 0] Al 2 O 3 and (1 1 1) Al ‖(0 0 0 1) Al 2 O 3 . The layers exhibit smooth and atomically sharp interfaces in HREM studies. For low doses, indications are found that in situ ripening processes lead to self-organized arrangements of precipitates in chains parallel to the surface, and that the coalescence of precipitates is affected by the internal twin-structure of isolated Al precipitates. In addition, the transformation of the buried Al layer into a textured polycrystalline AlN layer by a subsequent high-dose nitrogen implantation is investigated.