Thin-Film Devices For Active Pixel Sensor Schemes Enabling High Density And Large-Area Sensors

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 >100x 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.