On-Wafer Characterization of Varactor Using Resonating Microprobes

An uncertainty analysis is developed for one-port Q-factor measurements. It is shown that better than 2% measurement accuracy is expected for high-Q resonators provided that the coupling is close to the critical. The developed uncertainty analysis is then used to define the measurement accuracy of the resonance technique, which is introduced here for on-wafer characterization of high-Q varactors. The approach is simple and is more accurate if compared to broadband impedance measurements. The utility/validity of the proposed approach is demonstrated via measurements of the test varactors based on thin BSTO film.