Performance Comparison of SOI-Based Temperature Sensors for Room-Temperature Terahertz Antenna-Coupled Bolometers: MOSFET, PN Junction Diode and Resistor

Abstract

Assuming that the 0.6-μm silicon-on-insulator (SOI) complementary metal–oxide–semiconductor (CMOS) technology, different Si-based temperature sensors such as metal-oxide-semiconductor field-effect transistor (MOSFET) (n-channel and p-channel), pn-junction diode (with p-body doping and without doping), and resistors (n+ or p+ single crystalline Si and n+ polycrystalline Si) were designed and characterized for its possible use in 1-THz antenna-coupled bolometers. The use of a half-wave dipole antenna connected to the heater end was assumed, which limited the integrated temperature sensor/heater area to be 15 × 15 µm. Our main focus was to evaluate the performances of the temperature sensor/heater part, and the optical coupling between the incident light and heater via an antenna was not included in the evaluation. The electrothermal feedback (ETF) effect due to the bias current was considered in the performance estimation. A comparative analysis of various SOI bolometers revealed the largest responsivity (Rv) of 5.16 kV/W for the n-channel MOSFET bolometer although the negative ETF in MOSFET reduced the Rv. The noise measurement of the n-channel MOSFET showed the NEP of 245 pW/Hz1/2, which was more than one order of magnitude smaller than that of the n+ polycrystalline Si resistive bolometer (6.59 nW/Hz1/2). The present result suggests that the n-channel MOSFET can be a promising detector for THz applications.

Roadmap of Terahertz Imaging 2021

“…They were realized in silicon wafers, where the readout integrated circuits had been prefabricated to employ VOx film as a bolometer active layer, whose changes in the resistance can be detected and converted to the output voltage or current signals [194]. Other routes in microbolometers evolution are related to search of new materials, for instance, La 0.7 Sr 0.3 Mn O3 thin films as active device layers [195], silicon-on-insulator (SOI), CMOS technology employing different Si-based temperature sensors, such as metal-oxide-semiconductor field-effect transistor, pn-junction diode, and various resistors as possible antenna-coupled bolometers [196]. An interesting concept can be their confluence with metamaterials, e.g., metallic split-ring resonators, integrated into micro-bridge structures of THz microbolometer arrays to enhance the absorption of THz radiation in different materials, like thermal sensitive vanadium oxide film [197].…”

MOSFET Physics-Based Compact Model Mass-Produced: An Artificial Neural Network Approach

“…At a low gate voltage, the surface potential in the middle of the channel is determined by gate−channel work function differences. The surface potential of the drain and source terminal are raised by the PN junction[ 37 ], which is induced by different doping types of channel and source/drain terminals, and are hardly affected by . When increases from 0 (V) to 1.4 (V), the surface potential in the channel increases due to the electrical field induced by gate voltage , while the potential at the drain/source terminal stays almost fixed.…”

On-Chip Modification of Titanium Electrothermal Characteristics by Joule Heating: Application to Terahertz Microbolometer

“…Comparative analyses of these devices with other materials (Vox, VO 2 , Ti, SiGe, etc. as sensing material) and devices (MOSFET, PN junction diode and resistor-based sensors) have also been reported previously [ 27 , 38 ]. While we have previously established that the narrow width effect is detrimental to superior device performance, and it is understood that the meander shape helps the enhanced responsivity but does not improve NEP, here we have proposed a method in nanomaterial processing to further enhance the device performance by on-chip modification of Ti thermistors after fabrication by a feasible Joule heating and highlighted the possible issues that may be encountered by technologists.…”

“…Based on our familiarity in this field from previous extensive studies on the design and development of Ti on-chip microbolometers [ 24 , 25 , 26 , 27 , 37 , 38 , 39 , 40 ], the current report is focused on the on-chip modification of Ti electrothermal characteristics after fabrication by Joule heating, aiming at a terahertz microbolometer as a possible application. Our previous understanding on the importance of tuning of material properties like narrow width effect, grain size, TCR and resistivity in feature miniaturization for enhanced device performance, responsivity and NEP has been useful here.…”