Abstract
We report the first demonstration of three-dimensional (3D) integrated CMOS image sensors with pixel-parallel A/D converters (ADCs), thereby meeting the demand for high resolution and high frame rate imaging. Photodiode (PD) and inverter layers were directly bonded with the damascened Au electrodes to provide each pixel with in-pixel A/D conversion. We designed ADC with a pulse frequency output and fabricated a prototype sensor with 64 pixels. The developed sensor successfully captured video images and confirmed excellent linearity with a wide dynamic range of more than 80 dB, which showed feasibility of pixel-level 3D integration for high-performance CMOS image sensors.
