High gain gate/body tied NMOSFET photo-detector on SOI substrate for low power applications

• Published in: Solid-state electronics Vol. 44; no. 3; pp. 535 - 540
• Main Authors: Zhang, Weiquan, Chan, Mansun, Huang, Ru, Ko, Ping K
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.03.2000
• ISSN: 0038-1101; 1879-2405
• DOI: 10.1016/S0038-1101(99)00260-9

In this paper, we report the performance of a novel photo-detector fabricated on an SOI substrate using a standard DTMOS process. The photo-detector is formed by connecting the NMOSFET gate and body. The gate-body terminal is left floating so that the potential can be modulated by illumination. The depletion region induced by the floating gate separates the optically generated electron–hole pairs in the direction perpendicular to the current. This increases the body potential and induces positive charges to the gate due to the gate/body tie. It results in further turn on of the NMOSFET and extra optical current. A wide signal range of more than six orders of magnitude and a maximum responsivity of 1.2×10 3 A/W have been obtained with an operating voltage as low as 0.2 V. The behavior of the device under scaling is also discussed.