Electronic qubit circuits have been required to operate at temperatures near absolute zero – although a number of developments have sought to lift that restriction. Quantum computers therefore need high performance and low power control electronics with operating temperatures ranging from 4.2K down to well below 1K.
The research paper due to be presented at the virtual VLSI Symposia on Technology and Circuits, June 15 to 19, report high performance achieved at ultralow temperatures for short-channel transistors, with on current greater than 1mA/micron and off current below the equipment accuracy and less than 1fA.
The circuits made use of the one of the features of FDSOI – forward back biasing – to achieve the same efficiency from room temperature down to 100mK.
The paper examines the physical origins of MOSFET mismatch at ultralow temperature, highlighting the impact of charge fluctuation increase on threshold voltage and current gain factor (beta) variation.
The researchers also conclude that the increase in Vth and beta at low temperature remains low compared with room temperature values and other CMOS technologies. As a result the same circuits could be used at both ultra-low temperature and room temperature.
Paper T-N3-1 "Variability Evaluation of 28nm FD-SOI Technology at Cryogenic Temperaturesdown to 100mK for Quantum Computing" B. Cardoso Paz et al., CEA-Leti/STMicroelectronics/Institut Néel
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