A Parasitic Extraction Strategy for Four-Terminal Power Devices

Abstract:
An extraction strategy for the parasitic elements of power devices with a Kelvin source connection is presented. The extraction is conducted by measuring the S-parameters of the device under test with a vector network analyser, converting them to Z-parameters and deducting the capacitive, inductive and resistve elements from the obtained data. The extracted model also considers mutual inductances in between the terminals, which cannot be neglected when expanding the terminal count from three to four. The extraction procedure is conducted with 7 different wide-bandgap semiconductor devices and the resulting parasitic shell is verified with circuit simulations. The results show that the inductive properties of the transistor are mostly dependent on the device package. With the proposed parasitic extraction procedure, the device parasitics can be accurately extracted, resulting in an average impedance error of less than 6% over the whole frequency range from 1MHz to 300 MHz.