High-Speed Metal-Semiconductor-Metal Photo diode

High speed resonant cavity metal-semiconductor-metal (MSM) Schottky barrier photo detector is reported. Nickel is used as metal and quasi mono-crystalline silicon (QMS) with nanovoids is used as semiconductor material. QMS is sandwiched between thin nickel plates to obtain heterodyne characterization of MSM photo detector. QMS of suitable dimension shows significant enhancement of optical absorptance which in turn provides higher efficiency of the photo detector. A theoretical model of the photo diode is designed with a resonant cavity. The resonant cavity is chosen for obtaining higher quantum efficiency and the Schottky effect provides high speed to this photo detector. The micro cavity also causes wavelength selectivity accompanied by a drastic increase of the electric field at the resonant wavelength. The enhanced optical field provides high efficiency for faster transit time limited photodiodes with thinner absorption region. Appreciable improvement in results on speed, efficiency and responsivity is observed.