a-IGZO 3T-2C Pixel Circuit-Based Active-Matrix Self-Capacitive Fingerprint Sensor Array for Full-Area Multi-Identity Recognition

This study proposes an active-matrix self-capacitive touch-fingerprint sensor array using three standard staggered amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs) and two capacitors (3T-2C) pixel circuit architecture. TCAD simulations demonstrate that touch-induced self-capacitance modulates the gate potential of the sensing TFT, producing contact-area dependent output current. Moreover, SPICE circuit simulations confirm the pixel circuitfs transient response to touch events. Finally, a 256 × 256-pixel sensor array with a pixel size of 85 μm × 85 μm (298 ppi) is manufactured, achieving an exceptionally high signal-to-noise ratio (SNR) exceeding 114.40 dB. Furthermore, multi-identity recognition is demonstrated by combing the full-area sensor array with a specific signal processing algorithm. This work provides a manufacturable high-performance touch-fingerprint pixel circuit design for large-scale human-machine interaction interfaces with enhanced security.