Fully CMOS integrated programmable charge-to-digital readout operating at cryogenic temperature for semiconductor qubits

We present a compact CMOS readout electronics for spin qubits based on the single-electron transistor (SET) current measurement. The spin-state to digital conversion consists of integrating the current of the SET used for the spin to charge conversion feeding a programmable threshold comparator to provide a digital output of the qubit state. We achieve a microsecond time resolution with a 1 mW power consumption at 4.2 K. Compared to RF reflectometry-based readout, our solution does not require off-chip components allowing a reduction of the power consumption and the occupation area.