Silicon substrates with buried distributed Bragg reflectors for resonant cavity-enhanced optoelectronics

We report on a commercially reproducible silicon wafer with a high-reflectance buried distributed Bragg reflector (DBR). The substrate consists of a two-period DBR fabricated using a double silicon-on-insulator (SOI) process. The buried DBR provides a 90% reflecting surface. We have fabricated resonant cavity-enhanced Si photodetectors with 40% quantum efficiency at 860 nm and a full-width at half-maximum of 29 ps suitable for 10 Gbps data communications. We have also implemented double-SOI substrates with 90% reflectivity covering 1300 and 1550 nm for use in Si-based optoelectronics.