On the manipulation of phosphorus diffusion as well as the reduction of specific contact resistivity in Ge by carbon co-doping

摘要

In this work, the manipulation of phosphorus diffusion as well as the reduction of the specific contact resistivity in Ge by carbon co-doping is explored. It is found that there is an optimum condition for carbon implantation to suppress the rapid P diffusion effectively. For such a condition, the implanted carbon sits at the half range of the pre-amorphized Ge layer. In this case, both the diffusion of P in the amorphous layer and in the Ge virtual substrate beyond the amorphous/crystal (a/c) interface can be effectively manipulated. Except the control of P diffusion, the specific contact resistivity (ρ_c) between as-formed NiGe and the Ge substrate in the presence of C can be also reduced, compared with the reference without C. At 500°C germanidation temperature, the pc values are reduced from 1.1×10~(-4) Ω-cm~2 and 2.9×10~(-5) Ω-cm~2 for NiGe/n- and p-Ge contacts without carbon to 7.3×10~(-5) Ω-cm~2 and 1.4×10~(-5) Ω-cm~2 for their counterparts with carbon, respectively.