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 Pc 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 ρ
_c
values of 7.5 × 10
^-10
and 2.1 × 10
^-9
Ω · cm
²
are extracted by MRA-TLM for Ni/p
⁺
-GeSn and Ti/p
⁺
-GeSn contacts, respectively, which are in good agreement with 9.5×10
^-10
and 2.6×10
^-9
Ω·cm
²
extracted numerically by the two-layer distributed-resistor-network model (TDM), qualifying the proposed MRA-TLM for the extraction of ultralow Pc down to sub-10
^-9
Ω · cm
²
regime. In contrast, the Pc extracted by the conventional TLM-based method is more than three times higher due to the parasitic metal resistance.