Source: AIP Publishing Scilight, By Adam Liebendorfer
Cryogenic use of complementary metal oxide semiconductor (CMOS) transistors has garnered interest for providing control and readout circuitry in future quantum sensing and information technologies. At cryogenic temperatures, however, CMOS devices can deviate from standard transistor behavior.
Working in a joint Brown University-NIST collaboration on cryogenic magnetic sensor arrays, Zaslavsky et al. have observed and proposed a new application for the bistability that occurs in bulk CMOS transistors. Due to impact ionization changing the transistor body, the drain current exhibits sharp current jumps and stable hysteretic loops as a function of gate voltage, a finding that can be potentially used as a memory element.
“It should be noted that our memory only works at cryogenic temperatures, but we found that the retention time in our devices is surprisingly long, making the memory effectively nonvolatile on the time scales relevant to quantum sensing and computation,” said author Alexander Zaslavsky.
The approach was demonstrated for both n-type and p-type commercial-foundry 180 nanometer-process CMOS transistors when operated at voltages exceeding 1.3 to 1.5 V at cryogenic temperatures.
As various quantum computation schemes based on solid-state qubits advance towards practical implementation, Zaslavsky hopes the group’s work further stokes interest in filling future needs for compact capacitorless cryogenic memory fully compatible with the standard CMOS process.
The group looks to further characterize the performance parameters of cryogenic silicon transistors for low-temperature applications, such as their work on high-resolution imaging of magnetic fields.
Source: “Impact ionization-induced bistability in CMOS transistors at cryogenic temperatures for capacitorless memory applications,” by A. Zaslavsky, C. A. Richter, P. R. Shrestha, B. D. Hoskins, S. T. Le, A. Madhavan, and J. J. McClelland, Applied Physics Letters (2021). The article can be accessed at https://doi.org/10.1063/5.0060343.