Wednesday, March 20, 2024

Artilux announces room temperature GeSi SPAD

HSINCHU, Feb. 22, 2024 /PRNewswire/ -- Artilux, the renowned leader of GeSi (germanium-silicon) photonics technology for CMOS (complementary metal-oxide-semiconductor) based SWIR (short-wavelength infrared) sensing and imaging, announced today that the research team at Artilux has made a breakthrough in advancing SWIR GeSi SPAD (single-photon avalanche diode) technology, which has been recognized and published by Nature, one of the world's most prestigious scientific journals. The paper, titled "Room temperature operation of germanium-silicon single-photon avalanche diode," presented the Geiger-mode operation of a high-performing GeSi avalanche photodiode at room temperature, which in the past was limited to operation at a low temperature below at least 200 Kelvin. Nature's rigorous peer-review process ensures that only research of the highest caliber and broadest interest is published, and the acceptance and publication of the paper in Nature is another pivotal mark in exemplifying Artilux's leadership in CMOS-based SWIR sensing and imaging.

The research work, led by Dr. Neil Na, CTO of Artilux, has unveiled a CMOS-compatible GeSi SPAD operated at room temperature and elevated temperatures, featuring a noise-equivalent power improvement over previously demonstrated Ge-based SPADs by several orders of magnitude. The paper showcases key parameters of the GeSi SPAD, including dark count rate, single-photon detection probability at SWIR spectrum, timing jitter, after-pulsing characteristic time, and after-pulsing probability, at a low breakdown voltage and a small excess bias. As a proof of concept, three-dimensional point-cloud images were captured with TOF (direct time-of-flight) technique using the GeSi SPAD. "When we started the project, there were overwhelming evidence in the literature indicating that a room-temperature operation of GeSi SPAD is simply not possible," said Dr. Na, "and I am proud of our team turning the scientific research into a commercial reality against all odds."

The findings set a new milestone in CMOS photonics. The potential deployment of single-photon sensitive SWIR sensors, imagers, and photonic integrated circuits shall unlock critical applications in TOF sensors and imagers, LiDAR (light detection and ranging), bio-photonics, quantum computing and communication, artificial intelligence, robotics, and more. Artilux is committed to continuing its leadership in CMOS photonics technology, aiming to further contribute to the scientific community and photonics industry.

Abstract of article in Nature (Feb 2024):
The ability to detect single photons has led to the advancement of numerous research fields. Although various types of single-photon detector have been developed, because of two main factors—that is, (1) the need for operating at cryogenic temperature and (2) the incompatibility with complementary metal–oxide–semiconductor (CMOS) fabrication processes—so far, to our knowledge, only Si-based single-photon avalanche diode (SPAD) has gained mainstream success and has been used in consumer electronics. With the growing demand to shift the operation wavelength from near-infrared to short-wavelength infrared (SWIR) for better safety and performance, an alternative solution is required because Si has negligible optical absorption for wavelengths beyond 1 µm. Here we report a CMOS-compatible, high-performing germanium–silicon SPAD operated at room temperature, featuring a noise-equivalent power improvement over the previous Ge-based SPADs by 2–3.5 orders of magnitude. Key parameters such as dark count rate, single-photon detection probability at 1,310 nm, timing jitter, after-pulsing characteristic time and after-pulsing probability are, respectively, measured as 19 kHz µm−2, 12%, 188 ps, ~90 ns and <1%, with a low breakdown voltage of 10.26 V and a small excess bias of 0.75 V. Three-dimensional point-cloud images are captured with direct time-of-flight technique as proof of concept. This work paves the way towards using single-photon-sensitive SWIR sensors, imagers and photonic integrated circuits in everyday life.



  2. Congrats to the team, great work and fantastic achievement! They had a clear roadmap defined early on, worked closely with the foundry on the technology and executed flawlessly.


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