Low-Cost and High-Speed SOI Waveguide-Based Silicide Schottky-Barrier MSM Photodetectors for Broadband Optical Communications

Silicon-on-insulator waveguide-based silicide Schottky-barrier metal-semiconductor-metal (MSM) photodetectors were fabricated using a simple low-temperature Si-process. Without optimization, the detector achieves a 3-dB bandwidth of ~ 7 GHz at -3-V bias and a responsivity of ~ 19 mA/W at -1-V bias, with very weak dependence on wavelength ranging from 1520 to 1620 nm. Compared to the silicide Schottky-barrier photodiode with the same NiSi₂ absorber, the MSM detectors offer the benefits of high speed, large responsivity, and ease of fabrication. Approaches for optimization are addressed.