An Analog CMOS Silicon Photomultiplier Using Perimeter Gated Single Photon Avalanche Diodes
Perimeter gated single photon avalanche diodes (PGSPADs) have been shown to mitigate premature edge breakdown without unduly increasing the area of the device. PGSPADs are three terminal devices. In this paper, we develop a probability based SPICE model for the PGSPAD and fully characterize an <inline formula> <tex math notation="LaTeX"$18 \times 18$ /tex math>/inline formula> pixel analog PGSPAD based CMOS silicon photomultiplier (SiPM) The noise model is derived using theories of carrier thermal generation, carrier diffusion, and inter band tunneling. Parameters are derived using fabricated PGSPAD devices and model validity is verified with experimental measurements. The designed PGSPAD SiPM is implemented in standard <inline formula> <tex math notation="LaTeX"$0.5~\mu \text{m} /tex math>/inline formula> 2 poly, 3 metal CMOS process, and is characterized for dark current, sensitivity, and signal to noise ratio (SNR) throughout the visible spectral range for varying bias voltages. Models show that the reduction of dark events in the PGPSAD is primarily caused by a reduction in band to band tunneling. Thus, as a function of the applied gate voltage the PGPSAD shows an improvement of SNR over a range of 1 to 1150. The sensitivity of the presented SiPM is <inline formula> <tex math notation="LaTeX"$1.06 \times 10^{3} /tex math>/inline formula> A/W/cm<sup>2</sup> The designed PGSPAD SiPM shows great promise over standard SiPM for applications, such as neutron detection which requires high sensitivities and high SNRs.
IEEE Transactions on Circuits and Systems I: Regular Papers