EPITAXIAL REALIGNMENT OF POLYCRYSTALLINE SI LAYERS BY RAPID THERMAL ANNEALING

It is shown that both the kinetics and the mode of realignment of As doped polysilicon films deposited onto crystalline silicon substrates, strongly depend on the morphology of the interfacial native oxide film. During rapid thermal annealing the as deposited and doped polycrystalline layers realign via the lateral growth of large epitaxial columns in a way similar to secondary recrystallization. In layers submitted to a high temperature anneal before the As implantation, the realignment occurs by the planar motion of the whole interface towards the surface of the layers, and can be achieved at low annealing temperatures and for short times, with a reduced redistribution of the dopant atoms.