A Fast and Sensitive Schottky Photodiode with Surface Plasmon Enhanced Photocurrent and Extremely Low Dark Current for High-Frequency Applications in Near-Infrared

High-speed, high-photo response, low-dark current photodetectors with monolithic integration compatibility on a single silicon chip have a vital role in fast optical communication. Schottky barrier junctions provide ultra-high frequency band-width, which makes them suitable for high speed data rate optical transition system. In this paper, we proposed the novel design of a fast Silicon Schottky photodiode with reduced dark current and enhanced photocurrent to produce an acceptable photo-to-dark current ratio. A differential Schottky diode is used in series with the designed Schottky photodiode to reduce the final dark current delivered to the next signal conditioner electronics. A periodic plasmonic array is applied on the metallic Schottky contact layer to localize the illuminated light in the depletion region of Schottky contact and increase light absorption, which results in enhanced photocurrent. The simulation of the device shows a photo-to-dark current ratio of 2.7 × 10 4 at room temperature and 1V biasing voltage which is much greater than the reported data. Moreover, the design results in a CMOS-compatible photodiode with 28-time reduced dark current and 3.3-time photocurrent enhancement with ultrafast impulse response of 3 ps, and response time of about 18 ps that are attractive for ultra-fast data communication applications in 850 nm region.