Implantation and Activation of Phosphorus in Amorphous and Crystalline Germanium Layers

Abstract

We have investigated phosphorus implantation and activation in amorphous and crystalline Ge layers, deposited on Si substrates. The structure of the Ge layer has only limited influence on the dopant profile and diffusion after annealing. Surprisingly, crystalline Ge layers show better electrical results after implantation and dopant activation. For the amorphous layer, the solid phase epitaxy process is influenced in the neighborhood of P, leading to point defects, which inhibit electrical activation. This result implies that when a crystalline Ge layer is amorphized during implantation of high doses, the dopant activation can be significantly reduced. Reduced temperature ramping improves activation of P in amorphous Ge layers.