Single-Photon Avalanche Diode with Enhanced NIR-Sensitivity for Automotive LIDAR Systems

Area of Science:

• Photonics and Semiconductor Devices
• Automotive Sensing Technologies

Background:

• Automotive Light Detection and Ranging (LIDAR) systems require highly sensitive detectors for accurate environmental perception.
• Existing near-infrared (NIR) detectors often face trade-offs between sensitivity, fill factor, and operational voltage.

Purpose of the Study:

• To develop a novel single-photon avalanche diode (SPAD) with enhanced NIR sensitivity for advanced automotive LIDAR applications.
• To achieve high photon detection efficiency (PDE) and fill factor (FF) while maintaining low breakdown voltage.

Main Methods:

• Fabrication of a SPAD using 0.18 μm CMOS technology incorporating two custom layers.
• Characterization of the SPAD's performance, including PDE, FF, breakdown voltage, and dark count rate (DCR).
• Evaluation of ranging performance at 870 nm and across a temperature range of 25-132 °C.

Main Results:

• The developed SPAD achieved a high PDE of 19.4% and an FF of 33.1% at 870 nm.
• Low breakdown voltage of approximately 20.5 V was recorded.
• Ranging experiments successfully measured distances from 50-180 cm, demonstrating minimal impact from DCR variations.

Conclusions:

• The novel CMOS SPAD demonstrates significant potential for next-generation automotive LIDAR systems due to its enhanced NIR sensitivity and robust performance.
• The device's characteristics, including high PDE and stable operation over a wide temperature range, meet critical automotive requirements.