Researchers in Korea have developed a short range single-photon avalanche diode (SPAD) with improved timing jitter on a commercial 40nm process.
The researchers at the Korea Institute of Science and Technology (KIST) and SK hynix developed the SPAD on a commercial 40nm back-illuminated CMOS image sensor process for the first time. This enables the identification of objects at the mm level in consumer applications.
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A SPAD is a high performance sensors that can detect single photons and is extremely difficult to develop. To date, only Sony of Japan has successfully commercialized SPAD-based LiDAR based on its 90nm back-illuminated CMOS image sensor process and supplied to Apple.
The Sony SPAD design shows better efficiency than back-illuminated devices reported in the literature, but the timing-jitter performance of about 137~222ps is insufficient for user discrimination, gesture recognition, and accurate shape recognition of objects required in short- and mid-range LiDAR applications say the team at KIST.
The single-photon sensor element developed by the team, led by Dr. Myung-Jae Lee at the Post-Silicon Semiconductor Institute, has significantly improved the timing-jitter performance by more than two times to 56 ps, and the distance resolution has also been improved to about 8 mm, which has great potential for short and mid-range LiDAR sensor element.
As the device was developed based on the 40nm back-illuminated CMOS image sensor process, a semiconductor process for mass production, through joint research with SK hynix, it is expected to be immediately localized and commercialized.
“If commercialized as a core source technology for semiconductor LiDAR and 3D image sensors, it will greatly enhance our competitiveness in next-generation system semiconductors, which are Korea’s strategic industries,” said Myung-Jae Lee, principal investigator at KIST.