Solid-state qubit manipulation and read-out fidelities are reaching fault-tolerance, but quantum error correction requires millions of physical qubits and thus a scalable quantum computer architecture. To solve signal-line bandwidth and fan-out problems, microwave sources required for qubit manipulation might be embedded close to the qubit chip, typically operating at temperatures below 4 K. Here, we perform the first low temperature measurements of a 130 nm BiCMOS based SiGe voltage controlled oscillator. The device maintains its functionality from 300 K to 4 K. We determined the dependence of frequency and output power on temperature and magnetic field up to 5 T and measured the temperature influence on noise performance. While the output power tends to increase, the frequency shift is 3 % for temperature and 0.02 % for the field dependence, respectively, both relevant for highly coherent spin qubit applications. We observe no improvement on output noise, but increased output flickering.
@article{arxiv.1804.09522,
title = {30 GHz-voltage controlled oscillator operating at 4 K},
author = {Arne Hollmann and Daniel Jirovec and Maciej Kucharski and Dietmar Kissinger and Gunter Fischer and Lars R. Schreiber},
journal= {arXiv preprint arXiv:1804.09522},
year = {2018}
}