First Near-Ultraviolet- and Blue-Enhanced Backside-Illuminated Single-Photon Avalanche Diode Based on Standard SOI CMOS Technology

Abstract

We present the world's first backside-illuminated (BSI) single-photon avalanche diode (SPAD) based on standard silicon-on-insulator (SOI) complementary metal-oxidesemiconductor (CMOS) technology. This SPAD achieves a good dark count rate (DCR) after backside etching, comparable to DCRs of BSI SPADs fabricated on bulk wafers. Unlike bulk-wafer-based BSI SPADs, which typically suffer from poor violet and blue sensitivity, the proposed BSI SPAD features increased near-ultraviolet sensitivity as well as significant sensitivity in the violet and blue spectral ranges, thanks to the ultrathin-body SOI. To the best of our knowledge, this is the best result ever reported for any BSI SPAD in the standard CMOS technology. In addition, it also shows high sensitivity at long wavelengths thanks to the interface between silicon and silicon-dioxide layers. Therefore, it achieves a photon detection probability over 26% at 500 nm and 10% in the 400-875 nm wavelength range at 3 V excess bias voltage. The timing jitter is 119 ps full width at half maximum at the same operation condition at 637 nm wavelength. For the proposed BSI SPAD, the buried oxide layer in SOI wafers is used as an etching stop during the wafer backside-etching process, and therefore it ensures the excellent performance uniformity in large arrays.

A Review on the Recent Progress of Silicon‐on‐Insulator‐Based Photodetectors

“…The world's first backside‐illuminated (BSI) single‐photon avalanche diode fabricated with standard SOI CMOS technology is shown in Figure 7b. [ 42 ] This device achieves a good dark count rate (DCR), comparable with DCRs of BSI SPADs fabricated on bulk wafers. In addition, this SPAD features increased sensitivity in near‐ultraviolet, violet, blue, and also a wide wavelengths spectrum.…”

Room-temperature waveguide-coupled silicon single-photon avalanche diodes

“…Similarly, Morgan et al 44 demonstrated an improvement in the responsivity of an evanescently coupled PD by arranging doped regions as fingers. Additionally, reducing the dark counts of the SPAD can be achieved by introducing a doped isolation layer between the junction and the substrate or using a silicon-oninsulator (SOI) substrate to reduce the volume of the detector and to prevent undesired charged carriers from reaching the active region of the SPAD 23,[45][46][47][48] . These refinements of the junction design have the potential to significantly improve the performance of the waveguide-coupled Si SPADs in the future.…”

3D Photon-To-Digital Converter for Radiation Instrumentation: Motivation and Future Works

“…The BSI configuration is mainly used for near-infrared applications [ 70 , 95 ], where photons are absorbed over tens of microns. A recent work shows that some blue-enhanced/NUV architectures are also possible for the BSI configuration [ 110 ]. The FSI approach works mainly for the blue and UV range of the spectrum, since the penetration depth of these photons is below one micron ( Figure 11 ) and therefore, inside the depleted region.…”