Semiconductor devices with single-photon avalanche diodes and light scattering structures

A semiconductor device comprising:

• a substrate;
• a photosensitive area formed in the substrate;
• a microlens formed over the photosensitive area;
• and
• a plurality of light scattering structures in the substrate over the photosensitive area, wherein, in a first portion of the substrate, there is a first non-zero number of the light scattering structures per unit area, wherein, in a second portion of the substrate, there is a second non-zero number of the light scattering structures per the unit area, wherein the second non-zero number is greater than the first non-zero number, wherein the microlens has an outer periphery, and wherein the first and second portions of the substrate are both, in a direction parallel to a surface normal of the substrate, directly overlapped by an area defined by the outer periphery of the microlens.

A semiconductor device comprising:

• a substrate;
• a photosensitive area formed in the substrate;
• a microlens formed over the photosensitive area;
• and
• a plurality of light scattering structures in the substrate over the photosensitive area, wherein, in a first portion of the substrate, there is a first non-zero number of the light scattering structures per unit area, wherein, in a second portion of the substrate, there is a second non-zero number of the light scattering structures per the unit area, wherein the second non-zero number is greater than the first non-zero number, and wherein the first portion of the substrate forms a ring around the second portion of the substrate.