De-embedding method-based electrical resistivity characterisation scheme for a small brittle pillar-shaped material

An electrical resistivity evaluation method for a pillar-shaped solid material, especially a brittle thermoelectric Bi2Te3, is presented with short compensation based on a probing apparatus with four-spring pins. The method eliminates the process of modelling a complex contact resistance, resulting in a simple but reproducible characterisation without any contamination on the surface in comparison to either a conventional paste or welding contact. Furthermore, it enables a small electrical or thermoelectric material <2 mm thick to be appropriately evaluated, which can erect and align a pillar-shaped material with electrical terminals, in spite of a small surface area. To extract the resistivity of a Bi2Te3 pillar with the volume of 2 × 2 × 1.6 mm, Alumina 6061-T6 material identical with that of Bi2Te3 was used as a reference material for the short compensation. Thus, the modelled resistance and its resistivity were 2.46 ± 0.11 mΩ and 6.15 ± 0.28 Ω-μm, respectively, in the range of 2–10 kHz, demonstrating the validity of the method.