Indirect optical crosstalk reduction by highly-doped backside layer in single-photon avalanche diode arrays

Željko Osrečki* (Corresponding Author), Tihomir Knežević, Lis K. Nanver, Tomislav Suligoj

*Corresponding author for this work

    Research output: Contribution to journalArticleAcademicpeer-review

    1 Citation (Scopus)


    A method of reducing indirect optical crosstalk in single-photon avalanche diode arrays is investigated by TCAD simulations. The reduction is accomplished by taking advantage of an enhanced optical absorption in a highly-doped Si layer on the backside of the wafer. A simulation environment was developed to give information about optical crosstalk by incorporating the experimental optical constants of the materials constituting the crosstalk-reduction layer. It is shown that the indirect optical crosstalk is greatly reduced by increasing the thickness and doping of the layer. A crosstalk reduction of 5 orders of magnitude is gained with addition of 1-μm-thick PureB / α -Si stack for the array processed on a p-type substrate, while the same reduction is achieved with a 1-μm-thick highly-doped Si layer (As, 1.1×1020cm-3) for an array processed on an n-type substrate.

    Original languageEnglish
    Article number152
    JournalOptical and quantum electronics
    Issue number3
    Publication statusPublished - 1 Mar 2018



    • UT-Hybrid-D
    • PureB
    • Single-photon avalanche diode (SPAD)
    • SPAD array
    • Indirect optical crosstalk

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