Active pixel sensor readout circuit using indium–tin–zinc-oxide thin-film transistors for image sensor applications

Abstract

In this study, we describe an active pixel sensor (APS) readout circuit using indium–tin–zinc-oxide (ITZO) thin-film transistors (TFTs). The APS readout circuit with a pixel size of 90 μm was fabricated using ITZO TFTs with a channel length of 2 μm, and its performance was experimentally evaluated. The ITZO TFTs were found to have good low-frequency noise performance with an extracted Hooge’s parameter (α H) of 3.5 × 10−3, and the APS exhibits a high DC voltage gain of ∼0.81 with satisfactory linearity in a wide output voltage range of ∼6.4 V as well as manageable response times of less than 15 μs. The obtained results show the potential of our APS circuits to be applied to TFT-based image sensors with enhanced image quality.