Sweat Biomarker Sensor Incorporating Picowatt, Three-Dimensional Extended Metal Gate Ion Sensitive Field Effect Transistors

Abstract

Ion sensitive field effect transistors (ISFETs) form a very attractive solution for wearable sensors due to their capacity for ultra-miniaturization, low power operation, and very high sensitivity, supported by complementary metal oxide semiconductor (CMOS) integration. This paper reports for the first time, a multianalyte sensing platform that incorporates high performance, high yield, high robustness, three-dimensional-extended-metal-gate ISFETs (3D-EMG-ISFETs) realized by the postprocessing of a conventional 0.18 μm CMOS technology node. The detection of four analytes (pH, Na+, K+, and Ca2+) is reported with excellent sensitivities (58 mV/pH, −57 mV/dec­(Na+), −48 mV/dec­(K+), and −26 mV/dec­(Ca2+)) close to the Nernstian limit, and high selectivity, achieved by the use of highly selective ion selective membranes based on postprocessing integration steps aimed at eliminating any significant sensor hysteresis and parasitics. We are reporting simultaneous time-dependent recording of multiple analytes, with high selectivities. In vitro real sweat tests are carried out to prove the validity of our sensors. The reported sensors have the lowest reported power consumption, being capable of operation down to 2 pW/sensor. Due to the ultralow power consumption of our ISFETs, we achieve and report a final four-analyte passive system demonstrator including the readout interface and the remote powering of the ISFET sensors, all powered by an radio frequency (RF) signal.

Multiscale real time and high sensitivity ion detection with complementary organic electrochemical transistors amplifier

“…In Fig. 8b the sensitivity and operating range of the ion selective OECT complementary amplifier is benchmarked against various transistor-based ion sensors devices and architectures, including silicon 10 , 12 , porous-Si 14 , graphene 11 , zinc-oxide 13 , amorphous In-Ga-ZnO 15 , and organic materials technologies 16 – 19 , 43 . It shows that state-of-the-art ion sensors provide either wide operating range with small S N , or average S N over a narrow range.…”

“…So far, ion detection and monitoring have been widely addressed with several transistor-based technologies, comprising silicon, zinc-oxide, and graphene ion-sensitive field-effect transistors 10 – 13 , porous silicon extended-gate FETs 14 , amorphous indium-gallium-zinc-oxide dual-gate thin-film transistors 15 , organic electrolyte-gated FETs 16 and organic electrochemical transistors (OECTs) 17 – 19 . Among the aforementioned approaches, OECTs are gaining significant interest because they combine superior performance in terms of sensitivity and low-voltage operation, with the typical features of organic technologies, viz.…”

Interface Engineering of Si Hybrid Nanostructures for Chemical and Biological Sensing

“…[72] This type of system collects small volumes of sweat as it emerges from the surface of the skin and exploits capillary effects to deliver sweat to the channels of functionalized Si FET sensors for the detection of pH levels and concentrations of Na + /K + /Ca 2+ separately by using different ion-sensitive membranes as described in the previous session ( Figure 6E, left and middle). [72,77] Radio frequency signals power the sensors and support a readout/control interface ( Figure 6E, right). [77] These same multiplexed sensor architectures can be extended to many other types of analytes through schemes for functionalizing the sensing surfaces and for limiting the effects of Debye screening, as described previously.…”

“…[72,77] Radio frequency signals power the sensors and support a readout/control interface ( Figure 6E, right). [77] These same multiplexed sensor architectures can be extended to many other types of analytes through schemes for functionalizing the sensing surfaces and for limiting the effects of Debye screening, as described previously.…”

Comparison of Conventional and Maskless Lithographic Techniques for More than Moore Post-Processing of Foundry CMOS Chips

“…These processes are required to fabricate the additional patterned layers designed to add extra functionality to the underlying integrated circuitry, e.g. the addition of sensor technologies [20]- [24] or microelectromechanical systems (MEMS) [25]- [28].…”