Evaluation of LDMOS Device's Behavior at Cryogenic Temperatures

Trapped ion quantum computing (TIQC) with its high gate fidelities and coherence times is a leading quantum technology on the quest for a scalable, fault-tolerant quantum computer. Large-scale quantum computers will require cryogenic multiplexing of control signals. In the case of TIQC, these signals may have voltages of tens of volts. Thus, LDMOS devices will be employed in large-scale trapped ion quantum computers. In this publication, the cryogenic behavior of LDMOS is characterized down to a temperature of 4 K. It shows an increase in the threshold voltage and the kink effect for higher drain-source-voltages. For low voltages, another effect appears at cryogenic temperatures. Close to zero drain-source-voltage, a non-linearity drastically reduces the current through the device. This affects the settling time and the integrity of the applied control signals via the quantum computer's multiplexer.