Fabrication of high-speed resonant cavity enhanced Schottky photodiodes

We report the fabrication and testing of a GaAs-based high-speed resonant cavity enhanced (RCE) Schottky photodiode, The top-illuminated RCE detector is constructed by integrating a Schottky contact, a thin absorption region (In0.08Ga0.92As) and a distributed AlAs-GaAs Bragg mirror, The Schottky contact metal serves as a high-reflectivity top mirror in the RCE detector structure. The devices were fabricated by using a microwave-compatible fabrication process, The resulting spectral photo response had a resonance around 895 nm, in good agreement with our simulations, The full-width-at-half-maximum (FWHM) was 15 nm, and the enhancement factor was in excess of 6. The photodiode had an experimental setup limited temporal response of 18 ps FWHM, corresponding to a 3-dB bandwidth of 20 GHz.