Integrated NiSi waveguide heaters for CMOS-compatible silicon thermo-optic devices

We report the performance of NiSi-based heaters integrated with submicrometer silicon waveguides. The heaters were fabricated using a standard complementary metal-oxide-semiconductor (CMOS) silicidation process on a thin silicon slab laterally connected with a silicon rib waveguide. The intrinsic properties of such NiSi waveguide heaters were characterized by using them as thermo-optic phase shifters in a Mach–Zehnder interferometer. The power consumption $P_{\pi }$ for obtaining a π phase shift was measured to be as low as 20 mW, using CMOS-compatible drive voltages. The time constant of the thermo-optic response was less than $2.8\mu \text{s}$. Simulations suggest that a further reduction in the power consumption $P_{\pi }$ is feasible.