A team has characterized the operating margin of integrated current mirrors built on 4H-SiC CMOS technology after proton irradiation, evaluating their behaviour across a range of temperatures. The work quantifies how proton exposure affects the stability of these fundamental analogue circuits, fabricated on 4H silicon carbide, a wide-bandgap semiconductor particularly promising for electronics in radioactive environments.

4H silicon carbide is emerging as a key material for electronics destined for space, particle accelerators and nuclear reactors, where radiation degrades conventional silicon devices. Current mirrors are basic building blocks of nearly every analogue circuit, replicating a reference current with precision; understanding their radiation-induced degradation is a necessary step before entrusting them with critical systems.

The study measures the operating margins of these integrated CMOS circuits before and after proton irradiation, and evaluates them as a function of temperature. This dual variable —radiation and temperature— is what determines whether a circuit remains reliable in service, since threshold shifts and radiation-induced leakage currents depend strongly on the thermal regime.

The results provide concrete figures on how much the current window in which the mirror operates correctly narrows after irradiation, and how that margin evolves with temperature. The information allows design limits to be established for future 4H-SiC CMOS circuits intended to operate in proton radiation environments, such as space instrumentation or electronics aboard long-duration missions.