Pulsed time-of-flight 3D-CMOS imaging using photogate-based active pixel sensors

Abstract

A novel time-of-flight (ToF) 3D-image sensor based on photogate (PG) active pixel structures fabricated in a standard 0.35µm CMOS process is presented. Distance measurements are performed using a pulsed near-infrared (λ=905nm) laser with pulse widths of 30ns to 60ns for distance measurements up to 9m. The developed ToF pixel consists of a photogate (APG=30x30µm2) and four floating diffusion (FD) readout nodes, which enable the detection of reflected laser pulse delay and efficient ambient light suppression. Our fabricated sensor contains 4x16 pixels and exhibits a dynamic range of 56dB and a noise equivalent power of 4.46W/m2 using a single laser pulse.