On-Wafer Calibration Comparisons of Multiline TRL With Platinum and Gold Conductors

On-wafer calibrations are critical for measurements of embedded devices at the correct reference planes. A major challenge in on-wafer calibrations is the development of accurate calibrations that cover a frequency range from MHz to THz. Another challenge facing on-wafer measurements is the lack of calibrations that are directly traceable to the SI. The multiline Thru-Reflect-Line (TRL) calibration is a promising approach for high-frequency traceable on-wafer measurements. However, space considerations limit this approach to higher frequencies. Here, we compare the performance of several calibrations with different footprint requirements. Specifically, we compare three calibration kits: TRL fabricated with Au conductors, TRL fabricated with Pt conductors, and a series resistor (SR) calibration kit with Au conductors. We find that both the Au and Pt TRL calibration kits perform well above approximately 100 MHz. Then, we compare the performance of the different TRL calibration kits with reduced numbers of lines to assess the impact of device footprint on calibration quality. We find that changing the conductor material to more resistive Pt does not substantially improve the quality of the TRL calibration at low frequencies, while increasing the length of the longest line does.