A Simple and Accurate Pad-Thru-Short Deembedding Method Based on Systematic Analysis for RF Device Characterization

In this paper, a practical scalable cascade-based pad-thru-short deembedding methodology with the characteristic of wave propagation considered is presented for RF device characterization for the first time. Through an analysis, it is found that nonshielding thru and leg lines operate in quasi-transverse electromagnetic and quasi-transverse magnetic modes of wave propagation, respectively. To subtract the leg effect in different lengths based on transmission line parameters without shielding, this difference in operating modes between the thru and leg is addressed in this new method. Compared with a conventional scalable method with shielding, the presented method without violating the process design rules can achieve comparable results. Deembedding accuracy can be maintained without using numerous dummies. Therefore, this scalable deembedding method with simpler layout design and fabrication process is more practical for automatic ON-wafer measurements of different sized devices.