New gen of SPAD devices for near-infrared applications

17th November 2023

Sheryl Miles

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X-FAB Silicon Foundries SE, an analog/mixed-signal and specialty foundry, has introduced a near-infrared version of its single-photon avalanche diode (SPAD) device portfolio.

Following the previous generation launched in 2021, this version utilises the company’s 180nm XH018 process. An additional step in the fabrication workflow has led to significant signal increases while maintaining a low noise floor. This enhancement does not adversely affect other parameters such as dark count rate, afterpulsing, and breakdown voltage.

This latest variant marks X-FAB's expansion of its SPAD range, enhancing its capabilities in addressing various emerging applications where near-infrared (NIR) operation is essential. Applications include time-of-flight sensing in industrial settings, vehicle LiDAR imaging, biophotonics, FLIM research, and various medical-related activities. The new devices show improved sensitivity across the NIR band, with increases of 40% and 35% at 850nm and 905nm wavelengths, respectively.

The new SPAD devices simplify visible light filtering, as UV and visible light are already suppressed, leading to simpler filter designs with fewer components. They also share the same footprint dimensions as the previous generation, offering an easy upgrade path. Existing designs can be enhanced by simply swapping in the new devices.

X-FAB has developed a comprehensive Process Design Kit (PDK) for the NIR SPAD variant, including detailed documentation and application notes. Models for optical and electrical simulation are available to provide engineers with additional design support, facilitating the integration of these devices into their circuitry efficiently.

Heming Wei, Product Marketing Manager Sensors at X-FAB, stated: “Our SPAD technology has already gained a very positive market response, seeing uptake with a multitude of customers. Thanks to continuing innovation at the process level, we have now been able to develop a solution that will secure business for us within various NIR applications, across automotive, healthcare, and life sciences.”

The new NIR enhanced SPAD is currently available, allowing engineers to immediately begin designing with the new device.