On-Wafer Capacitor Characterization Including Uncertainty Estimates Up to 1.0 THz

Abstract

In this article, we extract the capacitance of shunt and series metal-insulator-metal capacitors from on-wafer S-parameter measurements in the WR1.0 (0.75–1.1 THz) waveguide band. These capacitors were fabricated in two different state-of-the-art terahertz semiconductor processes and measured with two different designs of via-stitched grounded coplanar waveguide calibration kits. We investigate the measurement uncertainty of extracting a shunt capacitance in the presence of probe positioning uncertainty, calibration kit process variation, and vector network analyzer electrical repeatability. We find that these uncertainty sources result in a large prediction interval that is 30.2% of the capacitor's value (14.9 ± 4.5 fF) at 900 GHz with the uncertainty from probe positioning as the largest contributor. This is the first time that an extensive uncertainty analysis has been performed on characterizing on-wafer devices at 1 THz. We quantify the precision of current calibration techniques and measurement equipment.