Elimination of the Parasitic Metal Resistance in Transmission Line Model for Extraction of Ultralow Specific Contact Resistivity

A metal-resistance-aware transmission line model (MRA-TLM) is developed to eliminate the parasitic metal resistance from the extraction of specific contact resistivity \rho _{c} in the metal/semiconductor contact. The proposed MRA-TLM is verified by Synopsys technology computer-aided design (TCAD) simulation, and a superior extraction accuracy as compared to the conventional TLM-based method is achieved. The proposed MRA-TLM is experimentally demonstrated in the metal/p + -Ge 0.95 Sn 0.05 (p + -GeSn) contacts. Ultralow \rho _{c} values of {7.5} \times {10}^{-{10}} and {2.1} \times {10}^{-{9}} \,\, \Omega \cdot \text {cm}^{{2}} are extracted by MRA-TLM for Ni/p + -GeSn and Ti/p + -GeSn contacts, respectively, which are in good agreement with {9.5} \times {10}^{-{10}} and {2.6} \times {10}^{-{9}} \,\,\Omega \cdot \text {cm}^{{2}} extracted numerically by the two-layer distributed-resistor-network model (TDM), qualifying the proposed MRA-TLM for the extraction of ultralow \rho _{c} down to sub- 10^{-{9}}\,\,\Omega \cdot \text {cm}^{{2}} regime. In contrast, the \rho _{c} extracted by the conventional TLM-based method is more than three times higher due to the parasitic metal resistance.