A Novel Fast-Turn-Around Ladder TLM Methodology with Parasitic Metal Resistance Elimination, and 2×10−10 Ω-cm2Resolution: Theoretical Design and Experimental Demonstration

A novel ladder transmission line method (LTLM) that features eliminated parasitic resistance from contact metal and access electrodes, simple fabrication process, and 2×10
^-10
Ω-cm
²
resolution for highly-accurate extraction of specific contact resistivity (ρc) in the ~ 10
^-10
to 10
^-9
Ω-cm
²
regime is demonstrated. The current distribution and extraction of ρcln LTLM are verified by TCAD and numerical distributive-resistor-network method, respectively. The extraction error caused by the current spreading and crowding in LTLM are modeled, and design guidelines to achieve 10
^-10
Ω-cm
²
resolution for ρc extraction are provided. By applying LTLM to the Ni/p
⁺
-Ge
_0.95
Sn
_0.05
contact, a record-low ρc down to 4.0±2.0×10
^-10
Ω-cm
²
was obtained. LTLM is insensitive to variation of metal resistance, unlike the refined TLM (RTLM) which could overestimate ρc by at least tens of times.