3D stackable cryogenic InGaAs HEMTs for heterogeneous and monolithic 3D integrated highly scalable quantum computing systems.

Three-dimensional (3D) co-integration of qubits and control/readout electronics is positively necessary for future highly scalable quantum computers. In this work, for the first time, we report 3D stackable cryogenic InGaAs HEMTs for heterogeneous and monolithic 3D integrated readout electronics. Furthermore, parasitic resistance analysis with three different structures was conducted to achieve extremely low power and low noise cryogenic III-V HEMT. Our 130-nm-gate devices exhibit f T and f MAX of 534 and 227 GHz at 5 K with very low power consumption. The f T value is the highest ever reported in cryogenic RF transistors. Such 3D integrated cryogenic electronics technology will play an essential role in future highly scalable computing systems.