High-responsivity photodetector using a grating-gate MOSFET in the 0.8-µm standard CMOS process

This letter reports a novel photodetector based on a metal-oxide-semiconductor field-effect transistor with a grating-gate structure, which was fabricated by employing the standard 0.8-µm complementary metal-oxide-semiconductor process. The use of a periodical slit structure allows the channel to be generated and exposed on the shallow surface, which makes the transmission and absorption of incident light more efficient, due to the surface plasmon resonance effect. The experimental results show that a responsivity (R_v) greater than 100 A/W was achieved within visible and near-infrared spectra under room temperature. Furthermore, a minimum noise equivalent power of 8.2 fW/Hz^0.5 at 15 Hz and a maximum detectivity (D*) of 1.7 × 10¹² Jones were obtained. It is believed that the photodetector will be widely used in communication or imaging systems.