Germanium-concentration dependence of arsenic diffusion in silicon germanium alloys

The germanium-concentration dependence of arsenic diffusion in relaxed silicon germanium (Si1-xGex) alloys with Ge content ranging from 0 to 40% has been investigated. Arsenic was implanted into relaxed epitaxial layers at 15 keV to a dose of 3x10(15) cm(-2), and diffusion during furnace and rapid thermal annealing was studied. Under equilibrium extrinsic conditions, the arsenic diffusivity increases exponentially with increasing Ge content in Si1-xGex. Under transient diffusion conditions, the arsenic diffusivity in Si1-xGex is retarded compared to the diffusivity for longer times, while a slight transient enhancement of As diffusion is observed in Si. The degree of transient retardation depends on the germanium concentration in the alloy. (C) 2004 American Institute of Physics.