Abstract: A semiconductor device may include a plurality of single-photon avalanche diode (SPAD) pixels. The semiconductor device may be a backside device having a substrate at the backside, dielectric layers on the substrate, metal layers interleaved with the dielectric layers, and a through silicon via (TSV) formed in the backside through the substrate and the dielectric layers. TSV seal rings may be formed around the TSV to protect the semiconductor device from moisture and/or water ingress. The TSV seal rings may be coupled to a high-voltage cathode bond pad and be coupled to offset portions of one of the metal layers to reduce leakage and/or parasitic effects due to the voltage difference between the cathode and the substrate. The TSV seal rings may also be merged with die seal rings at the edge of the substrate.

Abstract: An imaging device may include single-photon avalanche diodes (SPADs). To improve the sensitivity and signal-to-noise ratio of the SPADs, light scattering structures may be formed in the semiconductor substrate to increase the path length of incident light through the semiconductor substrate. To mitigate crosstalk, multiple rings of isolation structures may be formed around the SPAD. An outer deep trench isolation structure may include a metal filler such as tungsten and may be configured to absorb light. The outer deep trench isolation structure therefore prevents crosstalk between adjacent SPADs. Additionally, one or more inner deep trench isolation structures may be included. The inner deep trench isolation structures may include a low-index filler to reflect light and keep incident light in the active area of the SPAD.

Abstract: An imaging device may include single-photon avalanche diodes (SPADs). To improve the sensitivity and signal-to-noise ratio of the SPADs, light scattering structures may be formed in the semiconductor substrate to increase the path length of incident light through the semiconductor substrate. To mitigate crosstalk, multiple rings of isolation structures may be formed around the SPAD. An outer deep trench isolation structure may include a metal filler such as tungsten and may be configured to absorb light. The outer deep trench isolation structure therefore prevents crosstalk between adjacent SPADs. Additionally, one or more inner deep trench isolation structures may be included. The inner deep trench isolation structures may include a low-index filler to reflect light and keep incident light in the active area of the SPAD.

Abstract: An imaging device may include single-photon avalanche diodes (SPADs). To mitigate crosstalk, isolation structures may be formed around each SPAD. The isolation structures may include front side deep trench isolation structures that extend partially or fully through a semiconductor substrate for the SPADs. The isolation structures may include a metal filler such as tungsten that absorbs photons. The isolation structures may include a p-type doped semiconductor liner to mitigate dark current. The isolation structures may include a buffer layer such as silicon dioxide that is interposed between the metal filler and the p-type doped semiconductor liner. The isolation structures may have a tapered portion or may be formed in two steps such that the isolation structures have different portions with different properties. An additional filler such as polysilicon or borophosphosilicate glass may be included in some of the isolation structures in addition to the metal filler.

Abstract: An imaging device may include single-photon avalanche diodes (SPADs). To improve the sensitivity and signal-to-noise ratio of the SPADs, light scattering structures may be formed in the semiconductor substrate to increase the path length of incident light through the semiconductor substrate. To mitigate crosstalk, multiple rings of isolation structures may be formed around the SPAD. An outer deep trench isolation structure may include a metal filler such as tungsten and may be configured to absorb light. The outer deep trench isolation structure therefore prevents crosstalk between adjacent SPADs. Additionally, one or more inner deep trench isolation structures may be included. The inner deep trench isolation structures may include a low-index filler to reflect light and keep incident light in the active area of the SPAD.