A Cryogenic Ultra-Thin Body SiGeSn Transistor

Abstract

Transistors capable of operating at cryogenic temperatures are key components for the fast and energy-efficient control and readout of qubits. 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 to enhance Si-based Schottky junction field-effect transistors with ultra-thin layers of SiGeSn to address these issues. By combining single-elementary Al contacts to avoid dopant freeze-out and utilizing a multi-gate transistor architecture, which suppresses reverse junction leakage, a fivefold increase in on-current and a threefold increase in peak transconductance were achieved compared to a Si reference device. Measurements down to 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.