Single-Shot Readout Performance of Two Heterojunction-Bipolar-Transistor Amplification Circuits at Millikelvin Temperatures

M J Curry; M Rudolph; T D England; A M Mounce; R M Jock; C Bureau-Oxton; P Harvey-Collard; P A Sharma; J M Anderson; D M Campbell; J R Wendt; D R Ward; S M Carr; M P Lilly; M S Carroll

doi:10.1038/s41598-019-52868-1

Single-Shot Readout Performance of Two Heterojunction-Bipolar-Transistor Amplification Circuits at Millikelvin Temperatures

Sci Rep. 2019 Nov 18;9(1):16976. doi: 10.1038/s41598-019-52868-1.

Authors

M J Curry^{1

2

3}, M Rudolph⁴, T D England⁴, A M Mounce⁴, R M Jock⁴, C Bureau-Oxton^{4

5}, P Harvey-Collard^{4

5}, P A Sharma⁴, J M Anderson⁴, D M Campbell⁴, J R Wendt⁴, D R Ward⁴, S M Carr⁴, M P Lilly^{4

6}, M S Carroll⁴

Affiliations

¹ Department of Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico, 87131, USA. mjcurry@sandia.gov.
² Center for Quantum Information and Control, University of New Mexico, Albuquerque, New Mexico, 87131, USA. mjcurry@sandia.gov.
³ Sandia National Laboratories, 1515 Eubank Blvd SE, Albuquerque, New Mexico, 87123, USA. mjcurry@sandia.gov.
⁴ Sandia National Laboratories, 1515 Eubank Blvd SE, Albuquerque, New Mexico, 87123, USA.
⁵ Département de Physique et Institut Quantique, Université de Sherbrooke, Sherbrooke, Québec, J1K 2R1, Canada.
⁶ Center for Integrated Nanotechnologies, 1515 Eubank Blvd SE, Albuquerque, New Mexico, 87123, USA.

Abstract

High-fidelity single-shot readout of spin qubits requires distinguishing states much faster than the T₁ time of the spin state. One approach to improving readout fidelity and bandwidth (BW) is cryogenic amplification, where the signal from the qubit is amplified before noise sources are introduced and room-temperature amplifiers can operate at lower gain and higher BW. We compare the performance of two cryogenic amplification circuits: a current-biased heterojunction bipolar transistor circuit (CB-HBT), and an AC-coupled HBT circuit (AC-HBT). Both circuits are mounted on the mixing-chamber stage of a dilution refrigerator and are connected to silicon metal oxide semiconductor (Si-MOS) quantum dot devices on a printed circuit board (PCB). The power dissipated by the CB-HBT ranges from 0.1 to 1 μW whereas the power of the AC-HBT ranges from 1 to 20 μW. Referred to the input, the noise spectral density is low for both circuits, in the 15 to 30 fA/[Formula: see text] range. The charge sensitivity for the CB-HBT and AC-HBT is 330 μe/[Formula: see text] and 400 μe/[Formula: see text], respectively. For the single-shot readout performed, less than 10 μs is required for both circuits to achieve bit error rates below 10^-3, which is a putative threshold for quantum error correction.