CMOS Plasmon Detector With Three Different Body-Biasing MOSFETs

Abstract

A complementary metal-oxide-semiconductor (CMOS) plasmon detector using metaloxide-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-µm 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-µm 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.

Concurrent-Mode CMOS Detector IC for Sub-Terahertz Imaging System

“…where V OUT is the output voltage when the input power P IN is applied to the detector, V DCOFF is the output voltage without the incident signal, P D is the power density incident to the detector IC, and A EFF is the effective antenna area, which includes the integrated antenna and wavelength characteristics [9,13]. NEP is defined as the input power level that becomes equal to the noise generated from the detector itself; it is expressed using R V as:…”

“…When using a receiver antenna to transmit a THz signal to a detector, it is vital to determine the characteristics of the detector antenna and consider the input power equation of the detector to accurately analyze and measure the detector performance. The unit power density of the gyrotron measured at the detector position is 0.5 W/m 2 , and the effective area considering the receiving antenna gain at 200 GHz is 9.62 × 10 −8 m 2 [13]. The input power was calculated based on the measured performance, considering the difference in antenna gain according to the radiation area and similar antenna simulation values [21].…”

“…A CMOS detector capable of detecting a signal above the operating frequency is known as a self-mixing detector or a square row detector, and outputs a direct current (DC) voltage [12]. Body bias control can modify the electrical characteristics of the detector core to improve the performance by changing the subthreshold slope [13]. In addition, a CMOS detector with body bias control has demonstrated a wide dynamic range with strong voltage responsivity [13].…”

“…Body bias control can modify the electrical characteristics of the detector core to improve the performance by changing the subthreshold slope [13]. In addition, a CMOS detector with body bias control has demonstrated a wide dynamic range with strong voltage responsivity [13]. Detector bias changes the electric field effect of the detector, which requires various operating parameters.…”