Multiple-Wavelength Detection in SOI Lateral PIN Diodes With Backside Reflectors

This research details the potential of a microhotplate photo sensor, based on a silicon-on-insulator (SOI) lateral PIN (P + /P - /N + ) diode and a microheater, fabricated on a thin suspended membrane from a commercial 1.0-μm SOI complementary metal oxide semiconductor technology. A local annealing (30-min. microheating, at elevated temperature ~250 °C) is directly carried out onto the suspended diode to optimize device characteristics (e.g., leakage current, output optical response), for device long-term stability and industrial application. The optical performances of such SOI lateral PIN diodes with four different backside reflectors placed below them are fully investigated. Under same incident illumination, four specific output photocurrents and responsivities are therefore obtained due to the varied light absorption in the active Si film. By combining the photodiodes responses with the four backside reflectors (i.e., gold, aluminum, silicon substrate, and black silicon), multiple-wavelength detection can be straightforwardly achieved within the 450-900-nm wavelength range, which makes the SOI photodiode highly promising in red-green-blue sensing, gas analyzing or plasma monitoring applications.