Performance Limits and Cryogenic Characterization of a 13-to-18GHz CMOS Reflective-Type Phase Shifter for Qubit Control

This paper evaluates a reflective type phase shifter (RTPS) qubit control. First, the precision limits of the RTPS at room temperature are investigated, achieving a record low 0.01° root-mean-square error (RMSE) and 0.06° maximum absolute error across the 13-to-18 GHz band using single tone phase shifting. Subsequently, the device is characterized at cryogenic temperatures (4K) to evaluate its suitability for qubit control. At 4K, the RTPS achieves a minimum RMSE of 0.23°, with a maximum absolute error of 1.8°. The largest phase deviations occur near the estimated flatband voltage of the MOS capacitor, suggesting a contribution from random field-assisted ionization. An analysis of the performance degradation at cryogenic temperatures is provided.