Quantum computing has shown an increased interest in recent years. The basis of a quantum computer is a qubit, which is the quantum equivalent of a classical bit. Common qubit are only viable in a cryogenic environment and need electrical connections tooperate. For this, it is needed to solve the problem to bringing more qubits into the cryostat and connecting the quantum and the macroscopic world. The number of qubits per cryostat is limited just by the amount of interconnects and cooling power of the cryostat even if one neglect the other challenges which come with the increasing number of qubits integrated on one chip. This work investigates the performance of different integrated circuit architectures for operating at low temperature. The goal is to place the control electronics in close vicinity of the qubit itself and replace parts of the classical control electronics which by now are located at room temperature. The particular circuits investigated and implemented focus on the needs for operating a GaAs singlet triplet qubit. These qubits need frequency synthesis, biasing and readout circuitry to operate. This work includes the implementation of a digital controlled oscillator operating at a frequency of 500 MHz, a voltage controlled oscillator operating at 20 GHz and a 8-bit digital to analog converter with a sample rate of 250 MHz. The circuitry was fabricated on a 2 x 2 mm2 65 nm chip. The performance of the circuitry is evaluated at room temperature and in a closed-cycle Gifford-McMahon cryostat down to temperatures as low as 6 K. The results are compared and cryogenic effects are discussed
Dennis Nielinger (Sat,) studied this question.