Millikelvin cryo-mosfets dissipate only 2pW at 500MHz

SemiQon of Finland is claiming “the world’s first transistor capable of functioning efficiently in cryogenic conditions”.

“The transistors can be mass produced using existing CMOS fabs, with no new infrastructure required,” according to the company. In quantum computers the “transistor allows for control and readout electronics to be placed directly inside a cryostat, alongside the processors, but without causing the disruption that dissipation of heat brings to these systems”.

They are FD-SoI (fully-depleted silicon-on-insulator) mosfets, designed particularly for sub-1K operation by SemiQon, and made on 150mm SOI wafers.

Charge carriers are extended from doped contact regions into a 20nm thick intrinsic channel, which can be tuned by a front and back gates, it said.

The company estimates that a qubit controller made from 100nm wide 30nm long transistors could operate at 500MHz with each mosfet dissipating 2pW, and transistors could be made to run from a 40mV supply at 1GHz.

Given the amount of cooling available with ³He refrigeration, between 10⁷ and 10¹⁰ of the mosfets could run at mK temperatures, it said.

SemiQon expects to deliver its first cryo-CMOS transistors to customers in 2025 – use is forseen in quantum computing, HPC (supercomputing) and in space vehicles.

Founded in 2022 as a spin-off from European research institution VTT, SemiQon is aiming at building silicon-based quantum processors for the million-qubit era.