High-performance one-dimensional MOSFET array photodetectors in the 0.8-µm standard CMOS process

This paper reports a series of novel photodetectors based on one-dimensional array of metal-oxide-semiconductor field-effect transistors (MOSFETs), which were fabricated using the standard 0.8-µm complementary metal oxide semiconductor (CMOS) process. Normally, the metal fingers of MOSFET must be manufactured above active region in standard CMOS process, causing MOSFET insensitive to light. The proposed photodetectors use the metal fingers of MOSFETs in a one-dimensional array to form periodical slit structures, which make the transmittance of incident light higher, due to the surface plasmons (SPs) resonance effect. The number of parallel MOSFETs in one-dimensional array is 3, 5, 7, 9 and 11. The experimental results show that all responsivities (Rv) are greater than 10³ A/W within visible and near-infrared spectra under room temperature and a maximum value of 1.40 × 10⁵ A/W is achieved, which is at least one order of magnitude larger than those of published photodetectors. Furthermore, a minimum noise equivalent power (NEP) of 5.86 fW/Hz^0.5 at 30 Hz and a maximum detectivity (D*) of 2.21 × 10¹³ Jones are obtained. The photodetectors still have good signal-to-noise ratio when the bandwidth is 1 GHz. At the same time, the optical scanning imaging was completed by utilizing the photodetectors. This combination of high Rv, excellent NEP, high speed and broad spectrum range photodetectors will be widely used in imaging systems.