US 10,312,275 B2Granted

Single-photon avalanche diode image sensor with photon counting and time-of-flight detection capabilities

AssigneeSemiconductor Components Industries, LLC

InventorJaroslav Hynecek

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Abstract

A back side illuminated image sensor may operate using the single-photon avalanche diode (SPAD) concept in a Geiger mode of operation for single photon detection. The image sensor may be implemented using two layer stacking with a silicon on insulator (SOI) chip. The chip-to-chip electrical connections between the top level image sensing chip and the second level ASIC circuit chip may be realized at each pixel with a single bump connection per pixel. A light level signal may be obtained from pixels that have photon counting capabilities while a distance measurement signal for 3-dimensional imaging may be obtained from pixels that have time-of-flight (ToF) detection capabilities. Both types of pixels may be integrated within the same array and use the same SPAD structure placed on the top chip.

Claims20

Dependent claims

An image sensor comprising:

a first substrate;
a plurality of single-photon avalanche diodes in the first substrate;
a plurality of conductive interconnects;
a second substrate, wherein each single-photon avalanche diode has a corresponding conductive interconnect of the plurality of conductive interconnects that couples the first substrate to the second substrate;
a plurality of pulse counting circuits in the second substrate configured to generate light level signals, wherein each pulse counting circuit is coupled to a respective one of the plurality of conductive interconnects and wherein each pulse counting circuit is overlapped by a respective one of the single-photon avalanche diodes and a filter element that blocks more than 90% of incident infrared light;
and
a plurality of time-of-flight to voltage converter circuits configured to generate a signal with time-of-flight information, wherein each time-of-flight to voltage converter circuit is coupled to a respective one of the plurality of conductive interconnects and wherein each time-of-flight to voltage converter circuit is overlapped by a respective one of the single-photon avalanche diodes and a filter element that transmits more than 90% of incident infrared light.

4 more elements

An image sensor comprising:

a first plurality of single-photon avalanche diodes;
a second plurality of single-photon avalanche diodes;
a plurality of pulse counting circuits, wherein each pulse counting circuit is configured to generate light level signals in response to signals from a respective single-photon avalanche diode of the first plurality of single-photon avalanche diodes, wherein each pulse counting circuit comprises a respective capacitor and a respective current source circuit that supplies current pulses to the respective capacitor in response to pulses from a respective single-photon avalanche diode of the first plurality of single-photon avalanche diodes;
and
a plurality of time-of-flight to voltage converter circuits, wherein each time-of-flight to voltage converter circuit is configured to generate a signal with time-of-flight information in response to signals from a respective single-photon avalanche diode of the second plurality of single-photon avalanche diodes.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application: 15/496,915Filed 25 Apr 2017
Published: US 2018/0308881 A125 Oct 2018
Granted: 4 Jun 2019
Term ends: Not estimatedThe source records don’t support an estimate.

Classification22 codes

H10F 39/12
Integrated devices: image sensors
G01J 1/0411
Optical elements not provided otherwise, e.g. manifolds, windows, holograms, gratings: using focussing or collimating elements, i.e. lenses or…
G01J 1/0492
With spectral filtering: using at least two different filters
G01J 1/4228
Using electric radiation detectors: arrangements with two or more detectors, e.g. for sensitivity compensation