Performance analysis of an asymmetric metal semiconductor metal photodetector

Photodetectors are used in many applications of everyday life. Among the available photodetectors, MSM photodetectors are preferred as they provide good electrical bandwidth, fast response, small capacitance, a large active area and are easy to fabricate. MSM photodetectors have low quantum efficiencies and high dark current as compared to other available commercial photodetectors, which can further be improved. In this work, it has been shown that the. NPDR (normalized photocurrent to dark current ratio) of MSM photodetectors could be raised further with the incorporation of different metals to provide higher asymmetry. Asymmetric MSM-PD is used to suppress the dark current further by modifying the schottky barrier heights preferentially. The plots of NPDR for different metals on silicon substrate are compared and the Ti-SiGe-Ni structure has been shown to have better NPDR than other MSM Structures.