Speaker
Description
Transistors capable of operating at cryogenic temperatures are key components for the fast and energy-efficient control and readout circuits of qubit systems. However, the ultra-low power requirements and performance metrics are not met by conventional complementary metal-oxide-semiconductor technology, which has been optimized for room-temperature operation. Here, we propose Si-based Schottky junction field-effect transistors enhanced with ultra-thin SiGeSn layers to address these issues. By combining single-elementary Al contacts to avoid dopant freeze-out and using a multi-gate transistor architecture to suppress reverse junction leakage current, a fivefold increase in on-current and a threefold increase in peak transconductance were achieved compared to a Si reference device. Importantly, the presented SiGeSn SBFET delivers on-currents comparable to those of state-of-the-art GeSn transistors, while providing a better on/off ratio. Measurements down to 4.5 K revealed a drain current modulation over nine orders of magnitude with improved inverse subthreshold slopes of 20 mV/dec below 50 K and 50\% reduced threshold voltages, while the on-currents remain mostly temperature-independent, making the system interesting for cryogenic computing. To verify the capabilities of the proposed SiGeSn transistor for cryogenic electronics, a fundamental common-source amplifier circuit was investigated.