An over 120 dB wide-dynamic-range 3.0 μm pixel image sensor with in-pixel capacitor of 41.7 fF/um² and high reliability enabled by BEOL 3D capacitor process

Abstract

We realized a simultaneous-capture wide-dynamic-range image sensor with 3.0 μm pixels using novel in-pixel 3D capacitors located in BEOL. We achieved high capacitance density of 41.7 fF/μm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and low leakage current density of 3.6×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-10</sup> A/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> at 1 V by applying 3D structure and optimizing dielectric deposition process. TDDB investigations showed that estimated failure time at 125°C is more than 10 years. We demonstrated over 120 dB dynamic range image sensor with 3.0 μm pixels, which is enabled by this BEOL 3D capacitor process technology. (Keywords: image sensor, capacitor, 3D, BEOL, high reliability and wide dynamic range).