APartially Gated Regenerative Feedback Device for Ultra-High Sensitivity Biosensing Applications

This work proposes and investigates the performance of a feedback field effect device for biosensing applications. The device features a partially gated structure, enabling its function as a high-sensitivity, charge-modulated biosensor. The sensing principle relies on the regenerative feedback effect, giving rise to ultra-steep slope characteristics. 2D TCAD device simulations show a sharp turn-on profile in response to the conjugation of charged biomolecules on the ungated sensing surface. Consequently, a large shift in turn-ON voltage (AV
T
) exceeding 50% and a very high current sensitivity (~10
¹¹
) are observed, which are both considerably higher than the conventional FET-based biosensors. By simultaneously achieving a high ON-state current, low leakage, and ultra-steep subthreshold slope at low voltages, the device overcomes limitations of the existing steep slope FET biosensors. Given these attributes and compatibility with the standard semiconductor process technology, the proposed device is a promising candidate for future ultra-high sensitivity integrated biosensors.