Radio-frequency reflectometry in silicon carbide large-area transistors

TL;DR

This study explores RF reflectometry in large-area silicon carbide transistors, revealing how parasitic effects impact high-bandwidth readout at cryogenic temperatures and proposing solutions for scalable quantum systems.

Contribution

It demonstrates the limitations of RF readout in large-area transistors due to parasitic effects and introduces a modified circuit to restore sensitivity at low temperatures.

Findings

RF response degrades with decreasing temperature due to carrier freeze-out

Modified circuit configuration can restore RF sensitivity in cryogenic conditions

Parasitic pathways and device geometry critically affect RF readout performance

Abstract

Radio-frequency (RF) reflectometry is widely used for high-bandwidth readout of semiconductor quantum devices at cryogenic temperatures, but its application has mainly been limited to nanoscale structures with relatively small capacitances. Here, we investigate RF readout in a different regime by applying gate-based reflectometry to a large-area silicon carbide transistor with parasitic capacitances orders of magnitude larger than those of typical quantum devices, conditions normally expected to hinder RF readout. We observe a gate-dependent RF response which degrades and eventually vanishes as temperature is lowered, although MOSFET operation in DC transport is maintained down to deep cryogenic temperatures. We attribute this behaviour to impedance changes introduced by carrier freeze-out in the transistor drift region, and propose a modified circuit configuration designed to restore sensitivity under these conditions. These results establish how parasitic pathways and device geometry can limit RF readout, providing insight into the design of scalable cryogenic-CMOS quantum systems.