SPAD with 13% PDE @ 905nm

Imec, Katholieke Universiteit Leuven, Omnivision, and GPixel publish a joint paper "A Near-Infrared Enhanced Silicon Single-Photon Avalanche Diode with a Spherically Uniform Electric Field Peak" by Edward Van Sieleghem, Andreas Süss, Pierre Boulenc, Jiwon Lee, Gauri Karve, Koen De Munck, Celso Cavaco, and Chris Van Hoof.

"A near-infrared (NIR) enhanced silicon single-photon avalanche diode (SPAD) fabricated in a customized 0.13 μm CMOS technology is presented. The SPAD has a depleted absorption volume of approximately 15 μm x 15 μm x 18 μm. Electrons generated in the absorption region are efficiently transported by drift to a central active avalanche region with a diameter of 2 μm. At the operating voltage, the active region contains a spherically uniform field peak, enabling the multiplication of electrons originating from all corners of the device. The advantages of the SPAD architecture include high NIR photon detection efficiency (PDE), drift-based transport, low afterpulsing, and compatibility with an integrated CMOS readout. A front-side illuminated device is fabricated and characterized. The SPAD has a PDE of 13% at wavelength 905 nm, an afterpulsing probability < 0.1% for a dead time of 13 ns, and a median dark count rate (DCR) of 840 Hz at room temperature. The device shows promising performance for time-of-flight applications that benefit from uniform NIR-sensitive SPAD arrays."