Hexagonal AlN layers grown on sulfided Si(100) substrate

We have studied the influence of sulfide passivation on the initial stages of aluminum nitride (AlN)-layer nucleation and growth by hydride vapor-phase epitaxy (HVPE) on (100)-oriented single-crystalline silicon substrates. It is established that the substrate pretreatment in (NH$_4$)$_2$S aqueous solution leads to the columnar nucleation of hexagonal AlN crystals of two modifications rotated by 30$^\circ$ relative to each other. Based on the sulfide treatment, a simple method of oxide removal from and preparation of Si(100) substrate surface is developed that can be used for the epitaxial growth of group-III nitride layers.