Extended Data Fig. 5. Scalable manufacturing process based on DUV stepper lithography for thick high speed gold electrodes.

(a) Fabrication process flow of the electrodes. (b) Scanning electron micrography (SEM) of the cross-section of a silicon dummy wafer after step 2 in panel (a). The photoresist is colored in red, silicon dioxide in pink, and silicon in blue. (c) SEM of fabricated electrodes and LiTaO₃ waveguide. The gold is colored in yellow and LiTaO₃ in light blue.