Highly sensitive gate/body-tied metal-oxide-semiconductor field-effect transistor-type photodetector with wavelength-selective metal grid structure using standard complementary metal-oxide-semiconductor technology

In this research, a highly sensitive gate/body-tied metal-oxide-semiconductor field-effect transistor (MOSFET)-type photodetector with a wavelength-selective metal grid structure was designed and fabricated using 0.18-μm standard complementary metal-oxide-semiconductor technology. This device is composed of a floating gate that is tied to a well and a wavelength-selective metal grid is placed on top of each photodetector. The designed metal grid structure included one-dimensional and two-dimensional patterned metal layers. The amplified photocurrent of the gate/body-tied MOSFET-type photodetector was found to be more than 1000-fold that of a conventional n+/p-sub photodiode with the same area. To demonstrate the wavelength selectivity, we measured the drain current and transmittance of the photodetector as a function of wavelength.