Reliability of VO textsubscript 2-Based mmWave Switches Under 100 Million Thermal Cycles

We report the lifetime investigations of the reversible phase transition vanadium dioxide (VO textsubscript 2) thin film switches integrated with coplanar waveguide (CPW) under fast and direct thermal cycling. We observe that after 100 million thermal cycles, there is no degradation in the performance of VO2 shunt switches operating at 35– 45 GHz. S11 reflection coefficient as well as S21 transmission measurements (verified independently at both activated and inactivated states) show no statistical difference in port-to-port coupling of the VO2 switch as a function of a cycle number. This study is enabled by the integration of Joule heaters on chip at a close proximity to a shunt VO2 switch and a metallic CPW transmission line. Full-wave electromagnetic and multiphysics electrothermal finite element simulations are conducted to analyze the feasibility of the CPW design and the required time and power for thermal cycling. On-wafer mmWave measurements are carried out on the test vehicle after each thermal cycling phase.