SPAD device for excess bias monitoring

1. A SPAD device, comprising:

a single-photon avalanche diode having a breakdown voltage and a dark count rate,

a further single-photon avalanche diode having a further breakdown voltage and a further dark count rate, the further single-photon avalanche diode being integrated with the single-photon avalanche diode, and

the dark count rate being at least a factor 100 higher than the further dark count rate at least at one temperature below 25° C.

2. The SPAD device according to claim 1 , further comprising:

a p-n junction of the single-photon avalanche diode forming a base-collector junction of a structure of a bipolar transistor including an emitter region, a base region and a collector region, the bipolar transistor being configured for operation at a reverse collector-to-base voltage above a breakdown voltage.

3. The SPAD device according to claim 2 , further comprising:

a quenching component electrically connected with the base or the collector, and

a switching circuitry configured to apply a forward bias to the base-emitter junction.

4. The SPAD device according to claim 1 , wherein

the single-photon avalanche diode is provided for adjusting or controlling an excess bias voltage,

the further single-photon avalanche diode is provided for a detection of radiation, and

the single-photon avalanche diode and the further single-photon avalanche diode are configured for alternative operation.

5. The SPAD device according to claim 1 , further comprising:

a substrate of semiconductor material,

the single-photon avalanche diode comprising

a shallow well of a first type of conductivity in a deep well of an opposite second type of conductivity in the substrate, the deep well and the shallow well forming a p-n junction,

a junction-forming region arranged in the deep well under the shallow well, the junction-forming region having a doping concentration for the second type of conductivity, at the p-n junction said doping concentration being higher than a doping concentration of the deep well outside the junction-forming region, and

a shallow well region in the shallow well, the shallow well region having a doping concentration that is higher than a doping concentration of the shallow well outside the shallow well region,

the further single-photon avalanche diode comprising

a further shallow well of the first type of conductivity in the deep well or in a further deep well of the opposite second type of conductivity in the substrate, the further shallow well forming a further p-n junction with the deep well or further deep well,

a further junction-forming region arranged under the further shallow well, the further junction-forming region having a doping concentration for the second type of conductivity, at the further p-n junction said doping concentration being higher than a doping concentration of the deep well or further deep well outside the further junction-forming region, and

a further shallow well region in the further shallow well, the further shallow well region having a doping concentration that is higher than a doping concentration of the further shallow well outside the further shallow well region.

6. The SPAD device according to claim 5 , further comprising:

a peripheral region of the shallow well, the peripheral region reaching laterally beyond the junction-forming region.

7. The SPAD device according to claim 6 , wherein

the peripheral region of the shallow well is not covered by the shallow well region.

8. The SPAD device according to claim 5 , further comprising:

an opening in the shallow well region, the opening being arranged above the junction-forming region.

9. The SPAD device according to claim 8 , further comprising:

a polysilicon layer arranged above the opening.

10. The SPAD device according to claim 5 , further comprising:

a highly doped region of the second type of conductivity in the shallow well above the junction-forming region at a distance from the p-n junction, the highly doped region, the shallow well and the junction-forming region respectively forming an emitter region, a base region and a collector region of a structure of a bipolar transistor.

11. The SPAD device according to claim 5 , further comprising:

a deep well contact region in the deep well, the deep well contact region having a doping concentration that is higher than a doping concentration of the deep well.

12. The SPAD device according to claim 5 , wherein

the shallow well region does not cover the entire junction-forming region, and

the further shallow well region is arranged above the entire further junction-forming region.

13. A SPAD device, comprising:

a single-photon avalanche diode having a breakdown voltage,

a further single-photon avalanche diode having a further breakdown voltage, the further single-photon avalanche diode being integrated with the single-photon avalanche diode,

the single-photon avalanche diode having a dark count rate,

the further single-photon avalanche diode having a further dark count rate, and

the dark count rate being at least a factor 100 higher than the further dark count rate at least at one temperature below 25° C., wherein

the single-photon avalanche diode is provided for adjusting or controlling an excess bias voltage,

the further single-photon avalanche diode is provided for a detection of radiation, and

the single-photon avalanche diode and the further single-photon avalanche diode are configured for alternative operation.

14. A SPAD device, comprising:

a single-photon avalanche diode having a breakdown voltage, and

a further single-photon avalanche diode having a further breakdown voltage, the further single photon avalanche diode being integrated with the single-photon avalanche diode, wherein:

the single-photon avalanche diode having a dark count rate that is higher than a dark count rate of the further single-photon avalanche diode, and

a p-n junction of the single-photon avalanche diode forms a base-collector junction of a structure of a bipolar transistor including an emitter region, a base region and a collector region.