The bias-dependent capacitance of varactors can introduce harmonic distortion into the circuits where they are utilized. A gate capacitance model valid through inversion–depletion has been presented for GaN HEMT varactors in the drive for their utilization in monolithic GaN ASICs. This work focuses on the circuit and the methodology employed to accurately measure on wafer the harmonic distortion caused by one such device. The circuit is presented and its design considerations and operation trade-offs are discussed, followed by a presentation of the measurements resulting from its use. Second- and third-order harmonic distortion is recorded and presented, with Verilog-A model simulations used to fit the measured data. The model consists of a charge-based expression of the HEMT varactor capacitance, with a minimal number of parameters. The good fit of the model is demonstrated, proving both the suitability of the circuit used for the measurements and the validity of the capacitance model for real-world applications.

In light of sustainable development and the growing global emphasis on implementing green practices across all scientific sectors, the present work introduces a comprehensive framework with contemporary sustainability imperatives in nanofabrication cleanrooms. Recognizing the unique characteristics of cleanroom-based environments, which demand controlled conditions and strict procedures, the aim of the current work is to evaluate diverse nanofabrication scenarios with regard to their sustainability perspective with focus on operations at research- and pilot-line-level facilities.