Dopant Enhanced Diffusion for High n-type Doped Ge

We study the phosphorous (P) diffusion in Ge grown on Si substrate with different background doping and we find that the diffusion coefficient is extrinsic and is enhanced by over 500 times in Ge doped at 1x10(19) cm(-3) compared to diffusivity in intrinsic Ge. We study the loss mechanisms in Ge-on-Si. We show that the doping level is a result of the balance between in-diffusion and dopant loss. The high diffusivity in doped Ge leads to a uniform distribution of P in Ge with the concentration above 4.5x10(19) cm(-3).