Extraction of lumped RC elements representing substrate coupling of RF devices

Lumped RC elements that dominantly characterize parasitic coupling of RF devices to a silicon substrate are precisely determined from S parameters. Two-port test structures of substrate coupling were developed for a variety of geometries and dimensions of RF devices in a 65 nm CMOS technology. While the meshing of an entire test structure provides a greedy representation of a substrate coupling network and accurately captures its overall response given in S parameter, the subsequent translation with a pi-shaped model compactly attributes the substrate coupling to a few decisive RC elements at the vicinity of a device. Measurements and simulation evaluate the strengths of substrate coupling with the discrepancy of less than 3 dB from each other in the frequency range up to 8 GHz, and clearly analyze the relation of the resolved RC elements to the geometry of devices.