Expand this Topic clickable element to expand a topic
Skip to content
Optica Publishing Group
Journal Home About Issues in Progress Current Issue All Issues Feature Issues

Optical crosstalk in single photon avalanche diode arrays: a new complete model

Ivan Rech, Antonino Ingargiola, Roberto Spinelli, Ivan Labanca, Stefano Marangoni, Massimo Ghioni, and Sergio Cova

Open Access Open Access

Abstract

One of the main issues of Single Photon Avalanche Diode arrays is optical crosstalk. Since its intensity increases with reducing the distance between devices, this phenomenon limits the density of integration within arrays. In the past optical crosstalk was ascribed essentially to the light propagating from one detector to another through direct optical paths. Accordingly, reflecting trenches between devices were proposed to prevent it, but they proved to be not completely effective. In this paper we will present experimental evidence that a significant contribution to optical crosstalk comes from light reflected internally off the bottom of the chip, thus being impossible to eliminate it completely by means of trenches. We will also propose an optical model to predict the dependence of crosstalk on the distance between devices.

©2008 Optical Society of America

Full Article  |  PDF Article
More Like This
Timing and probability of crosstalk in a dense CMOS SPAD array in pulsed TOF applications

Sahba Jahromi and Juha Kostamovaara
Opt. Express 26(16) 20622-20632 (2018)

Quantum correlation measurement with single photon avalanche diode arrays

Gur Lubin, Ron Tenne, Ivan Michel Antolovic, Edoardo Charbon, Claudio Bruschini, and Dan Oron
Opt. Express 27(23) 32863-32882 (2019)

Variable-Load Quenching Circuit for single-photon avalanche diodes

Simone Tisa, Fabrizio Guerrieri, and Franco Zappa
Opt. Express 16(3) 2232-2244 (2008)

View More...

Cited By

Optica participates in Crossref's Cited-By Linking service. Citing articles from Optica Publishing Group journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (15)
Fig. 1.
Fig. 1. Cross-section of the planar SPAD structure used in our tests.

Download Full Size | PDF

Fig. 2.
Fig. 2. Layout of the tested SPAD arrays. The numbers from 1 to 7 and from 8 to 14 are used to identify the position of the single devices within the array.

Download Full Size | PDF

Fig. 3.
Fig. 3. Schematic representation of optical crosstalk between two devices A and B. When a primary signal photon triggers an avalanche in the SPAD A, secondary photons are emitted by the SPAD itself. These photons propagate through the bulk of the array and finally they are detected by the SPAD B.

Download Full Size | PDF

Fig. 4.
Fig. 4. Measured pseudo-crosstalk as a function of the position of the emitter and the detector. The two plots refer to the two rows of the array; the abscissas indicate the numbering of the SPAD as reported Fig. 2; the detector (in this case SPAD 1) is indicated by an arrow.

Download Full Size | PDF

Fig. 5.
Fig. 5. Dependence of the pseudo-crosstalk on the distance R between the emitter and the detector. The values shown represent the mean pseudo-crosstalk over all the couples at the same distance on the array. For comparison 1/R 2 curves are reported (dashed lines). Since crosstalk does not follow this law and it does not even decrease monotonically, also optical paths different from the direct ones have to be considered to describe this phenomenon.

Download Full Size | PDF

Fig. 6.
Fig. 6. Measurement of the light escaping from the bottom of the chip. The light is collected by a Hamamatsu C4880 Silicon CCD. Also the light escaping from the top surface was measured, in order to perform a comparison of the two contributions.

Download Full Size | PDF

Fig. 7.
Fig. 7. Increase in the total optical intensity reaching the detector due to a metal sheet manually placed under the chip.

Download Full Size | PDF

Fig. 8.
Fig. 8. Absorption coefficient of silicon as a function of the wavelength for different doping levels. The absorption coefficient for intrinsic silicon is taken from [13]. Coefficients (a)1.7·1017 cm-3, (b) 3.2·1017 cm-3, and (c)1019 cm-3 were reported by Spitzer and Fan in [14]. Coefficients (d) 2.4·1019 cm-3 and (e) 4·1019 cm-3 were reported by Schmid in [15].

Download Full Size | PDF

Fig. 9.
Fig. 9. Direct (Fig. (a)) and indirect (Fig. (b)) optical paths between SPAD A and SPAD B.

Download Full Size | PDF

Fig. 10.
Fig. 10. Measured SPAD emission spectrum for the devices shown in Fig. 1. The spectrum extends up to 1100 nm and beyond, thus indicating that even these spectral components can contribute to crosstalk.

Download Full Size | PDF

Fig. 11.
Fig. 11. Measured Photon Detection Efficiency for the tested planar SPADs.

Download Full Size | PDF

Fig. 12.
Fig. 12. Model developed to perform numerical simulations of optical crosstalk. The red dots correspond to the active regions of the SPADs and represent the possible emitting devices (as an example, the light emitted by one SPAD and reflecting off the bottom of the chip is shown in yellow). The black absorbing rings keep the effect of the isolation into account, whereas the bulk is modeled as a piece of uniform material (n-type silicon).

Download Full Size | PDF

Fig. 13.
Fig. 13. Simulated 2D intensity profile at the top surface of the chip with one emitter (at the top right of the image) turned on. The black dots represents the SPADs position on the array.

Download Full Size | PDF

Fig. 14.
Fig. 14. Overcoming of the critical angle for a single (a) and a double (b) reflection off the bottom of the chip. When this condition is reached (at a distance d 1 and d 2 from the emitter, respectively) all the optical power is reflected at the bottom silicon–air interface, therefore two variations of the intensity at the top surface of the chip can be seen in Fig. 13.

Download Full Size | PDF

Fig. 15.
Fig. 15. Simulated (solid line) and measured (dashed line) pseudo-crosstalk for the situation of Fig. 4. As before, the two plots refer to the two rows of the array; the abscissas indicate the numbering of the SPAD as reported Fig. 2; the detector (in this case SPAD 1) is indicated by an arrow. The numerical data are in very good agreement with the experimental results, thus indicating the developedmodel represents a helpful tool for the prediction of the dependence of crosstalk on the position of the devices within the array.

Download Full Size | PDF

Select as filters
Select Topics Cancel
Top
       
© Copyright 2024 | Optica Publishing Group. All rights reserved, including rights for text and data mining and training of artificial technologies or similar technologies.
Privacy | Terms of Use