We fabricate and characterize a polarizationdiversity 32 × 32 silicon photonics switch by newly introducing SiN overpass waveguides onto our nonduplicate polarization-diversity path-independent insertion-loss switch. The SiN overpass waveguides are used to simplify the optical paths with a uniform path length between the edge couplers and the switch matrix and significantly reduce the number of waveguide intersections. The switch chip is fabricated using a 300-mm silicon-on-insulator wafer pilot line. The fabricated switch comprises more than 7,600 components, making this the largest ever complementary-metal-oxidesemiconductor-based silicon photonics circuit. The switch chip is electrically and optically packaged and evaluated for a sampled port connection with 32 paths, with an average on-chip loss of ∼35 dB and an average polarization-dependent loss of 3.2 dB where 75% of the measured paths exhibit a loss of less than 3 dB. The differential group delay is measured to be 1.7 ps. The performance can be further improved by optimizing the device design.

A low-temperature, damage-free process for growing ultrathin (<6 nm) silicon dioxide (SiO 2 ) films was successfully developed. The excitation of low-pressure, highly concentrated O 3 gas using photons with energies less than 5.6 eV led to rapid growth rates of 2 and 3 nm within 1 and 5 min, respectively, even when the process temperature was as low as 200 C. The enhanced oxidation rate was due to an increased supply of O( 1 D) atoms at the Si surface. Transmission electron microscope images revealed that the SiO 2 film formed with a uniform thickness and a smooth, distinct SiO 2 /Si interface. Capacitance-voltage and current-voltage measurements showed that 200 and 300 C as-grown films had a satisfactorily low density of mobile ions and trap charges as well as ideal insulating properties.

No abstract

No abstract

No abstract