Sub-fF 130 nm MOS Varactor Characterization Using 6.8 GHz Interferometry-Based Reflectometer

Abstract

Nanometer-scaled communication devices for microwave and millimeter wave applications motivated innovative techniques in modeling and characterization. In this letter, an interferometry-based reflectometer (IBR), comprising Vector Network Analyser (VNA) and commercial devices, is implemented. Using sub-fF 130 nm thick-oxide accumulation MOS varactors from ST Microelectronics, IBR and VNA measurements are compared to a silicon-based model. A capacitance from 0.9 to 1.6 fF around 6.8 GHz is estimated. IBR demonstrates a root-mean-squared (RMS) error related to silicon-based model of 60 aF, while VNA has 70 aF in its best case. The mean accuracy is estimated at 40 aF and 11 aF respectively for VNA best case and IBR in C-V measurements. This letter demonstrates that IBR solution has smaller RMS error and better accuracy for C-V measurements than VNA.Index Terms-High-impedance microwave and millimeter wave instrumentation, interferometry-based reflectometer, sub-fF MOS varactor.

Fully Integrated Interferometry-Based Reflectometer for High-Impedance Instrumentation

“…Ferreira et al have previously presented an IBR architecture associating a VNA and on the shelves devices [4]. Our previous reflectometer experimentally proved that IBR is an appropriate solution to measure sub-fF capacitance variations with a better accuracy than standard VNAs.…”

“…In a similar architecture demonstrated in our previous work [4], Haddadi et al have included an amplifier between the IBR and the VNA receiver to increase measurements sensitivity [11]. This work includes an amplification gain playing a role of imaging zoom, but the outcome of IBR complexity and power consumption increase.…”

“…Towards a fully-integrated SMM, the authors have presented an Interferometry-Based Reflectometer (IBR) using transmission-based measurements [4]. Using a quite simple calibration technique, our previous work experimentally demonstrates IBR accuracy while measuring high-impedance microwave devices.…”

“…To manage the fully-integrated SMM challenges, a fullyintegrated reflection-based IBR is proposed. To consider power and area constrains of a monolithic microwave integrated circuit, this work aims an all-passive IBR using a simpler topology compared to our previous work [4]. The fullyintegrated IBR is proposed in the BiCMOS 55 nm technology for high-impedance microwave instrumentation of a DUT varactor varying from 0.65 fF to 0.95 fF.…”

“…The fullyintegrated IBR is proposed in the BiCMOS 55 nm technology for high-impedance microwave instrumentation of a DUT varactor varying from 0.65 fF to 0.95 fF. IBR measurement accuracy is compared with previous IBR using figures-of-merit introduced in [4]. Furthermore, fully-integrated IBR results are compared with the state-of-the-art of reflectometers using standard figures-of-merit proposed in [3].…”