Tensile strain in arsenic heavily doped Si

In this paper we highlight the existence of tensile stress in heavily arsenic-doped epitaxial silicon (Si:As) prepared by low pressure chemical vapor deposition. Despite the large size of As atoms compared to Si ones, we demonstrate with x-ray diffraction and convergent electron beam diffraction that the heavily doped epitaxial layers show a tetragonal lattice with a reduced out of plane parameter. Using positron annihilation spectroscopy, we highlight the formation of arsenic-vacancies defects during the growth. We show that the tensile strain is related to this type of defects involving inactive As atoms and not to the As active concentration. (c) 2007 American Institute of Physics.