A 1.2Mp 2.8 um 4-tap Indirect Time-of-Flight Sensor with 42% Quantum Efficiency at 940 nm Wavelength with Enhanced Angular Response

A 2.8 um 4-tap Indirect Time-of-Flight Sensor with 42% Quantum Efficiency (QE) at 940nm wavelength is presented in 1.2Mp. SiO grid is used for 6%p higher 940nm QE than tungsten grid. We also used 3×3 multiple small lenses per unit pixel to enhance angular response. The dark noise can cause depth accuracy degradation especially under dim received light from far object, therefore we optimized n-type photodiode implantation under higher annealing temperature, which showed dark noise reduction, and achieved demodulation contrast of 92% under 100 MHz demodulation frequency with 940nm VCSEL. Overall depth resolution is under 10mm at 0.3~ 1.2m range without wiggling calibration.