Wavelength-Tunable Si-Based InGaAs Resonant Cavity Enhanced Photodetectors Using Sol-Gel Wafer Bonding Technology

We report resonant cavity enhanced (RCE) InGaAs/Si photodetectors fabricated by sol-gel wafer bonding technology. The bonding temperature was 300°C. A 60-μm-diameter photodetector demonstrated dark current density of 0.59 pA/μm
²
at 0-V bias and 24.7 pA/μm
²
at 2-V reverse bias, peak responsivity of 0.7 A/W, and full-width at half-maximum (FWHM) of 6 nm around 1.55 μm. The 3-dB bandwidth of a 20-μm-diameter photodetector was 17.05 GHz under 1-V reverse bias voltage. Red shift of the resonant wavelength caused by thermo-optic effect was observed. The thermal tuning range achieved 15 nm.