4.6µm Low Power Indirect Time-of-Flight Pixel Achieving 88.5% Demodulation Contrast at 200MHz for 0.54MPix Depth Camera

This paper describes a 4.3e- RMS low noise 4.6µm Time-of-Flight pixel based on charge domain with kTC noise removal designed to enhance depth camera image quality. The pixel takes advantage of 6µm gradually doped epitaxial layer for 88.5% demodulation contrast at 200MHz and 18.5% QE at 940nm. Buried channel transfer gates are used to enable low capacitive switching and allowing best-in-class 1.4µW/pixel power consumption at 200MHz. The pixel is fully isolated due to deep trench isolation and the pixel bulk is biased at several hundreds of mV for low power Time-of-Flight sensor and system operation. The paper describes the design of 0.54Mpix camera (672 x 804 pixels) implementing demodulation circuits robust against EMI and multi-devices interferences. The performance of an indirect Time-of-Flight system is demonstrated with 1.0% depth noise under 40kLux at 30fps.