Thin‐Film Devices for Active Pixel Sensor Schemes Enabling High Density and Large‐Area Sensors

Abstract A novel and scalable method enabling the integration of dissimilar thin‐film devices for high density and large‐area sensors is demonstrated. The method is validated by integrating CdS/CdTe P‐N thin‐film diodes with poly‐Si thin‐film transistors (TFTs) in an active pixel sensor (APS) scheme. These devices have been used separately in low‐cost and large‐area applications such as liquid‐crystal displays (Poly‐TFTs) and solar cells (CdS/CdTe) and the methods allow a seamless integration that eliminates the use of discrete pixel‐to‐pixel bumping interconnections. APSs, consisting of a cascode TFT amplifier and a CdS/CdTe diode, are evaluated using pulsed light sources under several wavelengths and intensities. The results demonstrated a responsivity increase of >100× for the integrated sensors and well‐defined signal amplitude, as desirable for energy and intensity monitoring. The method enables the use of two dissimilar and remarkable devices in a wide range of applications such as X‐ray imagers, gamma‐ray detectors, and thermal neutron detectors, while offering large‐area and low‐cost compatibility. More importantly, the integrity and reliability of the diodes and TFTs are not affected by the integration process.