In order to enhance the performance and functionality of the pn-junction photodiode in silicon on insulator (SOI), surface plasmon antenna is introduced. In case of the 100-nm-thick silicon, external quantum efficiency of the photodiode can be increased by nearly an order of magnitude. The antenna shows wavelength and polarization selectivities, and incident angle dependence, and the peak wavelength and the polarization angle can be tailored only by changing the layout design. Consequently a variety of photodiodes with different characteristics can be integrated in a single chip. A wider application of this photodiode can be expected along with the evolution of the SOI-based large-scale integrated circuits (LSIs).
