Growth Characteristics of AlN Films Pyrolytically Deposited on Si

Abstract

AlN films prepared by the ammonolysis of AlCl₃·xNH₃ have been studied by transmission electron microscopy. The films are found to be mosaiclike arrays composed of numerous small crystallites. Average linear dimensions of the crystallites are dependent on deposition temperature and follow an inverse relationship, e.g., 1600 Å at 900°C and 150 Å at 1350°C. The number of crystallites per unit area is likened to a saturation density of stable nuclei which have formed according to an ``initially incomplete condensation of nuclei'' model. The refractory nature of AlN prevents extensive recrystallization and preserves a numerical relationship between the saturation number of nuclei and the number of crystallites. An epitaxial component of the AlN films on single‐crystal Si substrates is evident over a restricted temperature range, viz., 1100°–1300°C. The orientation relationship is (0001)_AlN ∥ (111)_Si and [112̄0]_AlN ∥ [22̄0]_Si.