Highly-Sensitive Gate/Body-Tied MOSFET-Type Photodetector Using Multi-Finger Structure

In this paper, we present a highly-sensitive gate/body-tied (GBT) metal-oxide semiconductor field-effect transistor (MOSFET)-type photodetector using multi-finger structure whose photocurrent increases in proportion to the number of fingers. The drain current that flows through a MOSFET using multi-finger structure is proportional to the number of fingers. This study intends to confirm that the photocurrent of a GBT MOSFET-type photodetector that uses the proposed multi-finger structure is larger than the photocurrent per unit area of the existing GBT MOSFET-type photodetectors. Analysis and measurement of a GBT MOSFET-type photodetector that utilizes a multi-finger structure confirmed that photocurrent increases in ratio to the number of fingers. In addition, the characteristics of the photocurrent in relation to the optical power were measured. In order to determine the influence of the incident the wavelength of light, the photocurrent was recorded as the incident the wavelength of light varied over a range of 405 to 980 nm. A highly-sensitive GBT MOSFET-type photodetector with multi-finger structure was designed and fabricated by using the Taiwan semiconductor manufacturing company (TSMC) complementary metal-oxide-semiconductor (CMOS) 0.18 um 1-poly 6-metal process and its characteristics have been measured.