Tip Avalanche Photodiode-A New Generation Silicon Photomultiplier Based on Non-Planar Technology

• Published in: IEEE sensors journal Vol. 21; no. 5; pp. 6024 - 6034
• Main Authors: Engelmann, Eugen, Schmailzl, Wolfgang, Iskra, Peter, Wiest, Florian, Popova, Elena, Vinogradov, Sergey
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.03.2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Avalanche diodes; Biophysics; Efficiency; Electric fields; Electric potential; Electrodes; Impurities; Junctions; LiDAR; Medical imaging; near-infrared; Particle physics; PDE; Photodiodes; Photomultiplier tubes; Photomultipliers; Photonics; Photons; Recovery time; red enhanced; Resistors; Silicon; Silicon photomultiplier; single photon; TAPD
• ISSN: 1530-437X; 1558-1748
• DOI: 10.1109/JSEN.2020.3041556

The Silicon Photomultiplier (SiPM) is a mature photodetector concept that is applied in a variety of applications ranging from medical imaging to automotive LiDAR systems. Over the last few years, improvements of the sensor performance are gradually approaching to a saturation. In this work we present our new concept to overcome the intrinsic limitations of planar configurations of electrodes. Our non-planar technology is based on focusing and enhancing the electric fields by tip-like electrodes. The shape of the electric field and the lack of typical micro-cell edges, allows us to exclude cell separation boundaries and eliminate dead space around active cell areas. Our design provides a high-density micro-cell layout with a high geometric efficiency. It resolves the well-known trade-off between the detection efficiency and the dynamic range. The first "Tip Avalanche Photodiode" (TAPD) prototypes show a remarkable geometric efficiency above 80% for a micro-cell pitch of 15<inline-formula> <tex-math notation="LaTeX">\mu \text{m} </tex-math></inline-formula>. This directly translates into a photon detection efficiency (PDE) record peak value of 73% at 600nm with respect to the state-of-the-art SiPMs. Moreover, the PDE remains above a value of 45% up to a wavelength of 800nm with another record value of 22% at 905nm. The reduced micro-cell capacity allows for a fast recovery time below 4ns, which improves the operation at high photon rates. Overall, the TAPD is anticipated to be a very promising SiPM generation for various wide-spectral and high-dynamic-range applications in health science, biophysics, particle physics and LiDARs.