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 pi 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 mus. Simulations suggest that a further reduction in the power consumption P(pi) is feasible.