Experimental Analysis of Repeatability and Calibration Residuals in On-Wafer Non-Contact Probing

We experimentally demonstrate the repeatability performance of non-contact probes for millimeter-wave (mmW) and terahertz (THz)-frequency on-wafer device characterization under typical laboratory settings. Akin to conventional contact probe measurements, the leading contribution to the overall uncertainty of non-contact measurements in mmW and THz bands is due to mechanical alignment repeatability that cannot be removed through on-wafer calibration. Nevertheless, measurement uncertainty for non-contact probes studied here through one-port and two-port measurements conducted in 140-750 GHz bands demonstrate excellent S-parameter measurement repeatability, as predicted by full-wave simulations, and is limited only by instrumentation drift.