ABSTRACT
The development of silicon photomultiplier (SiPM) is considered as one of the most promising innovations toward ideal photon detectors in the 1990s–2000s. Worldwide recognized due to superior photon number and time resolution, compactness, robustness, and low operating voltage, the SiPMs became detectors of choice in many application areas: nuclear medicine (TOF PET), high energy physics (calorimetry), astrophysics (Cherenkov telescopes), biophotonics (flow cytometry), quantum communications, and LIDARs. The majority of modern SiPMs are designed as an array of independent APD cells operated in a limited Geiger mode where an avalanche region is formed by a planar p-n junction. Now the planar SiPMs are approaching the physical limits of the design performance due to inactive borders at the cell periphery resulting in an inherent trade-off between photon detection efficiency (PDE) and dynamic range. This trade-off becomes especially challenging for the development of red and near-infrared (NIR) sensitive SiPMs. To overcome the limitations of the planar SiPMs, we developed the “Tip Avalanche Photodiode” (TAPD) – a new high-performance SiPM. The TAPD concept is based on the properties of tip-like electrodes to focus and enhance the electric field, to reduce the breakdown voltage and cell capacitance, and to eliminate the needs in the borders for a peripheral separation of the APD cells. First TAPD samples of 15 um pitch demonstrate the absolute record PDE of 73% at the peak sensitivity wavelength of 600 nm in comparison with the state-of-the-art SiPMs. Moreover, the PDE is above 45% in a range from 400 nm to 800 nm with another record value of 22% at 905 nm. Due to the low capacitance of the tips, the high PDE is also complemented with the fast single electron response and microcell recovery time of 4 ns which improves detection of intense photon fluxes and operations at ambient light conditions. Therefore, we expect that high performance and flexibility of nonplanar design make the TAPD a promising wide-spectral high-dynamic-range and fast-timing SiPM highly competitive with vacuum PMTs and MCPs, linear and Geiger mode APDs, and planar SiPMs in a wide range of radiation detection applications.
