Infrared Performance of Symmetric Surface-Plasmon Waveguide Schottky Detectors in Si

The internal quantum efficiency, responsivity, and sensitivity of symmetric surface-plasmon waveguide Schottky detectors in silicon are investigated theoretically at room temperature at λ₀ = 1310 and 1550 nm. The detectors consist of a thin metal stripe buried in Si, forming Schottky contacts along all metal/Si interfaces, with detection occurring via internal photoemission over the Schottky barriers. Several metals are considered for the stripe (Au, Ag, Al, Cu, CoSi₂). The internal quantum efficiency is significantly enhanced for stripes that are thin compared to the hot carrier attenuation length. Responsivities of 0.1 to 0.21 A/W and receiver sensitivities of -24 and -18 dBm are predicted for 1.5 and 10 GHz electrical bandwidths (~2.5 Gbit/s and >; 10 Gbit/s), respectively. This predicted performance, at room temperature, is competitive with the best cryogenically cooled conventional Schottky detectors and is adequate for optical interconnect and power monitoring. The detectors are attractive for applications requiring broadband (electrical and optical) infrared detectors in Si.