Scalable DC Filter System for Semiconductor Spin Qubits*

Over the past couple of years the complexity of gate defined quantum dots has dramatically increased. A 9 qubit device has been fabricated and tested in the Si/SiGe accumulation-mode device platform¹, but the overlapping gate design requires independent voltage biasing of thirty nine gate electrodes. Electrical noise on the gates increases the electron temperature and may limit coherence times on devices incorporating micromagnets for spin control². We develop a scalable low-pass filter system that supports up to 150 dc lines. The filter design is modular, can be readily expanded, and allows for easy repairs without complete disassembly of the filter system. The filters are located at the mixing chamber plate, have a roll off frequency of 2 MHz, and provide 15 dB of attenuation above 10 MHz.

¹D. M. Zajac, T. M. Hazard, X. Mi, E. Nielsen, and J. R. Petta, Phys. Rev. Applied 6, 054013 (2016).

²K. Takeda et al., Science Adv. 2, e1600694 (2016).