US 2021/0175376 A1 · SCATTERING STRUCTURES FOR SINGLE-PHOTON AVALANCHE DIODES

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. The light scattering structures may include a low-index material formed in trenches in the semiconductor substrate. The light scattering structures may have different sizes and/or a layout with a non-uniform number of structures per unit area. SPAD devices may also include isolation structures in a ring around the SPADs to prevent crosstalk. The isolation structures may include metal-filled deep trench isolation structures. The metal filler may include tungsten.

Claims20

Dependent claims

A semiconductor device comprising:

a substrate;
a single-photon avalanche diode formed in the substrate;
an isolation structure formed around a periphery of the single-photon avalanche diode;
and
a plurality of light scattering structures formed in the substrate over the single-photon avalanche diode.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application

16/948,100Filed 3 Sep 2020

Priority

4 Dec 2019

Published

10 Jun 2021

Term ends

Not estimatedThe source records don’t support an estimate.

Classification21 codes

H10F 77/959
For devices having potential barriers: for devices working in avalanche mode
G02B 3/06
With non-spherical faces: with cylindrical or toric faces
H04N 25/773
Comprising A/D, V/T, V/F, I/T or I/F converters: comprising photon counting circuits, e.g. single photon detection [SPD] or single photon…
H10F 30/225
The devices having only one potential barrier, e.g. photodiodes: the potential barrier working in avalanche mode, e.g. avalanche photodiodes

Scattering structures for single-photon avalanche diodes

Life of this patent

Scattering structures for single-photon avalanche diodes

Life of this patent

Abstract

Claims20