Cryogenic RF Transimpedance Amplifier in 22 nm SOI-CMOS for Control of a Qubit

The design and simulation of a cryogenic RF transimpedance amplifier (TIA) for signals around 20 GHz with millivolt amplitudes is presented in this paper. The TIA is part of an IC with a modulator system, where its primary application is to drive a semiconductor based spin qubit at temperatures around 100 mK. A 22 nm FDSOI CMOS technology is used for the circuit development. In post-layout simulations the TIA showed transimpedance magnitudes over 40 dB Omega and bandwidths larger than 1 GHz while dissipating less than 170 muW. Tuning options for the operating point and the frequency behavior where implemented to ensure functionality at cryogenic temperatures. The TIA performance allows to flip chip bond the modulator system in close vicinity to the qubit inside a dilution refrigerator. This setup can verify if the concept is feasible to upscale qubit numbers.