Abstract
A complementary metal–oxide–semiconductor (CMOS) plasmon detector using metal–oxide–semiconductor field–effect transistors (MOSFETs) biased at three different body voltages is proposed for high sensitivity and a wide dynamic range. The detection core consists of three differential MOSFET detectors biased at different body voltages based on the photoresponse variation depending on the body potential. The sensitivity of the proposed detector is improved through an increase in the nonlinearity owing to the uses of transistors biased by negative body voltages, and the dynamic range of the detector is widened through the parallel-connected detectors individually biased at different body voltages. A 200-GHz signal is simultaneously incident to the detection cores configured in-parallel through the integrated differential antenna, and DC voltages converted using the different photoresponsivity of the cores are current-combined at the preamplifier and amplified with a three-stage folded-cascode operational amplifier. Simulation and measurement results of the proposed detector designed using TSMC 0.25- $\mu \text{m}$ CMOS technology show that the negative body-biasing (set to 0, −0.2, and −0.4 V), in the MOSFET can improve the voltage responsivity of 2.63 times, the sensitivity by 2.9-fold compared to zero body-biasing, reaching a dynamic range of 11.1% in the CMOS plasmon detector. Raster-scanned imaging for 60- $\mu \text{m}$ thick copper tapes with a line width of 6–12 mm attached to 10-mm thick Styrofoam demonstrates that the signal-to-noise ratio of 200-GHz images can be improved from 25.5 dB to 30.6 dB when using the proposed detector with three different body-biased MOSFETs.
Highlights
Since Dyakonov and Shur first introduced the mechanism of plasma-wave detection in a field-effect transistor, plasmon detectors have been an attractive technology for measuring the magnitude of high-frequency signals above the cut-off frequency of the transistor when implemented using a low-cost semiconductor process [1]−[5]
Complementary metal−oxide−semiconductor (CMOS) detectors based on the plasmon-wave theory have had limited applicability in imaging applications within the terahertz band owing to low sensitivity and a narrow dynamic range compared to conventional compound semiconductor-based detectors, despite the many advantages in the implementation of the focal-plane array (FPA), such as a room-temperature operation, fast response time, and easy integration with read-out, control, and bias circuits [6]−[9]
The chopper is located at the focal position of the THz signal generated by off-axis parabolic (OAP) mirrors to minimize any disturbance by the blade blockage of the chopper, and the polarizer is placed to more minutely control the power of the wellpolarized THz signal from the gyrotron
Summary
Since Dyakonov and Shur first introduced the mechanism of plasma-wave detection in a field-effect transistor, plasmon detectors have been an attractive technology for measuring the magnitude of high-frequency signals above the cut-off frequency of the transistor when implemented using a low-cost semiconductor process [1]−[5]. To the best of the authors’ knowledge, it has yet to be reported that the sensitivity, dynamic range, and image SNR, which are important factors for the performance of the THz imaging system, can be improved by the body-bias control of the detection core transistor. It is not known whether the body voltage should be biased with forward or reverse voltages to improve the performance of the CMOS plasmon detector. It is necessary to conduct the study on the design configuration of the CMOS plasmon detector IC including the detection core transistors controlled with body-bias voltages from the perspective of a performance improvement in THz imaging. Raster-scanned images using the proposed detector IC have been provided to show the improvement of the quality of the THz imaging by the detector
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
