Waveguide SPAD Array Layout for NIR Detection With Low Timing Jitter

The patent divides the detector into multiple independent pixel elements, each with its own small SPAD junction. This segmentation allows each pixel to have low timing jitter while the array provides high photon detection efficiency through multiple detection opportunities. The segmentation principle resolves the contradiction by distributing the detection function across multiple small units rather than relying on a single large junction.

The patent transitions from a single large SPAD junction to a two-dimensional array of small SPADs. This dimensional change allows the system to achieve high photon detection efficiency through spatial distribution rather than increasing individual junction width, thereby maintaining low timing jitter while improving overall detection efficiency.

The patent implements a closed junction structure where the depletion region is fully extended into the substrate, creating a high electric field throughout the entire detection volume. This local quality change eliminates field-free regions, preventing carrier drift and diffusion tails, thereby achieving superior timing resolution. The closed junction design prioritizes timing precision over structural simplicity.

The patent changes the electrical field distribution parameter by implementing a closed junction with full substrate depletion. This parameter change transforms the electric field from having field-free regions (open junction) to being uniformly present throughout the detection volume (closed junction), eliminating the diffusion tail and improving timing resolution.

The patent uses an array of multiple shallow junction SPADs instead of a single deep junction SPAD. Each shallow junction maintains excellent timing resolution, while the array configuration increases the total detection probability for NIR photons through spatial distribution and multiple detection opportunities, resolving the efficiency limitation of individual shallow junctions.

The patent compensates for the limited silicon volume of shallow junctions by extending the detection capability into the spatial dimension through a two-dimensional array. This dimensional transition allows the system to achieve high photon detection efficiency through increased pixel count rather than increasing individual pixel depth, thereby maintaining both shallow junction timing advantages and high NIR detection efficiency.