Characterizing electron temperature and a cryogenic printed circuit board for spin-based quantum computing in Silicon

Phosphorous donors in silicon and gate-defined quantum dots are a primary candidate for spin-based quantum computing. For high fidelity quantum state readout, electron temperature should be significantly less than the Zeeman energy difference; high-frequency wiring is needed to allow for high-speed gate operation including qubit manipulation. To satisfy these operational frequency and low electron temperature requirements, we have developed a 6-layer cryogenic high frequency printed circuit board (PCB) with onboard filtering. The high-frequency PCB consists of 14 DC filtered lines, 16 medium frequency lines (up to a few GHz) for readout using DC charge sensing or RF reflectometry, 2 tank circuits, and 2 high-frequency microwave lines for transmission of signals up to 40 GHz. We will discuss, transmission characteristics, crosstalk, tank circuit characterization, and electron temperature measurements of single-electron transistors at cryogenic temperatures. Our current work is focused on using this cryogenic PCB with improved inline filtering to demonstrate robust charge sensing and single-shot spin readout using the RF-Reflectometry technique and DC charge sensing.