Highly Sensitive Bulk Silicon Chemical Sensors with Sub‑5 nm Thin Charge Inversion Layers

• Published in: ACS nano Vol. 12; no. 3; pp. 2948 - 2954
• Main Authors: Fahad, Hossain M, Gupta, Niharika, Han, Rui, Desai, Sujay B, Javey, Ali
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 27-03-2018; American Chemical Society (ACS)
• Subjects: charge inversion layer; CMOS gas sensors; CS-FET; electrostatic confinement; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; low power; tunable sensitivity; low power; CMOS gas sensors; CS-FET; tunable sensitivity; electrostatic confinement; charge inversion layer
• ISSN: 1936-0851; 1936-086X
• DOI: 10.1021/acsnano.8b00580

There is an increasing demand for mass-producible, low-power gas sensors in a wide variety of industrial and consumer applications. Here, we report chemical-sensitive field-effect-transistors (CS-FETs) based on bulk silicon wafers, wherein an electrostatically confined sub-5 nm thin charge inversion layer is modulated by chemical exposure to achieve a high-sensitivity gas-sensing platform. Using hydrogen sensing as a “litmus” test, we demonstrate large sensor responses (>1000%) to 0.5% H2 gas, with fast response (<60 s) and recovery times (<120 s) at room temperature and low power (<50 μW). On the basis of these performance metrics as well as standardized benchmarking, we show that bulk silicon CS-FETs offer similar or better sensing performance compared to emerging nanostructures semiconductors while providing a highly scalable and manufacturable platform.