Reduction of NiGe/n- and p-Ge Specific Contact Resistivity by Enhanced Dopant Segregation in the Presence of Carbon During Nickel Germanidation

This brief explores the specific contact resistivity (Pc) of NiGe/n- and p-Ge contacts with and without carbon pregermanidation implantation. It is found that in the presence of carbon, not only the thermal stability of NiGe films is improved, but also the Pc of the NiGe/n- and p-Ge contacts is reduced remarkably due to enhanced phosphorus (P) and boron (B) dopant segregation (DS) at the NiGe/Ge interface after nickel germanidation. At 500 °C germanidation temperature, the Pc values are reduced from 1.1 × 10-4Ω-cm2and 2.9 × 10-5Ω-cm2for NiGe/n- and p-Ge contacts without carbon to 7.3 × 10-5Ω-cm2and 1.4 × 10-5Ω-cm2for their counterparts with carbon, respectively.