Improved Performance of Zinc Oxide Thin Film Transistor Pressure Sensors and a Demonstration of a Commercial Chip Compatibility with the New Force Sensing Technology

A zinc oxide thin film transistor is developed and optimized that simultaneously functions as a transistor and a force sensor, thus allowing for scalable integration of sensors into arrays without the need for additional addressing elements. Through systematic material deposition, microscopy, and piezoelectric characterization, it is determined that an O2 rich deposition condition improves the transistor performance and pressure sensing characteristics. With these optimizations, a sensitivity of 4 nA kPa−1 and a latency of below 1 ms are achieved, exceeding the criteria for successful commercialization of arrayed pressure sensors. The functionality of 16 × 16 pressure sensor arrays on thin bendable glass substrates for integrated low weight and flexible touchscreen displays is fabricated and demonstrated and read‐out electronics to interface with the arrays and to record their response in real‐time are developed. Finally, the application of these sensors for mobile displays via their operation with an existing commercial touch integrated circuit controller is demonstrated. Zinc oxide thin film transistor pressure sensor arrays on bendable glass substrates are optimized by material characterization techniques and field‐effect transistor measurements for force sensing applications. The commercial viability of the technology is demonstrated by using an existing commercial touch integrated circuit controller to read out the sensor signal from the pressure sensor array.