Studies of linear properties of wafer probes and contacts for RF SAW/BAW device characterization

Abstract This paper investigates linear properties of RF wafer probes with a focus on the probe-to-wafer contact (PWC) and its impact on linear measurement results. First, the full two-port scattering parameters of the probes, including the PWC, are characterized experimentally. The results indicate that the probes can be regarded as transmission lines with a characteristic impedance of 50 ohms, including small transmission loss. The uncertainty associated with the linear properties of PWC is effectively characterized as a variation of the transmission loss, and its influence becomes significant when the device impedance is extremely large or small. It is also shown both theoretically and experimentally that the transmission loss is caused by PWC resistance. Furthermore, the mBVD model is applied to discuss the third-order nonlinearity of a temperature-compensated SAW resonator using the SiO 2 /128°YX-LiNbO 3 structure, and it is shown that fluctuations in the linear properties of the PWC give a small impact on nonlinearity measurements.