Room-temperature, 96×96 pixel 3D-stacked InGaAs/InP SPAD sensor with complementary gating for flash LiDAR

Area of Science:

• Photonics and Optoelectronics
• Integrated Circuits
• Sensor Technology

Background:

• Short-wave infrared (SWIR) imaging is crucial for various applications, including autonomous driving and robotics.
• Traditional LiDAR sensors often face limitations in terms of size, power consumption, and performance in challenging lighting conditions.
• 3D stacking offers a pathway to miniaturize and enhance sensor capabilities.

Purpose of the Study:

• To present a room-temperature, 3D-stacked flash LiDAR sensor operating in the SWIR spectrum.
• To demonstrate the sensor's ability to capture intensity images and depth maps with high accuracy.
• To evaluate the sensor's performance under varying lighting conditions and ranges.

Main Methods:

• Development of a 96x96 InGaAs-InP Single-Photon Avalanche Diode (SPAD) array on a top tier.
• Integration with a bottom tier featuring complementary cascoded gating for noise and afterpulsing reduction.
• Fabrication using 110-nm CMOS technology.
• Testing with a 1550nm laser and 3ns gating pulses.

Main Results:

• The sensor successfully generated intensity images and depth maps both indoors and outdoors.
• Achieved accurate ranging up to 100m with better than 2% accuracy.
• Demonstrated robust performance in 120 klux background light conditions.
• Operated with a 1550nm laser across a power range of 100μW to 3.1mW.

Conclusions:

• The presented 3D-stacked flash LiDAR sensor is a significant advancement for SWIR imaging.
• The sensor's performance validates the effectiveness of 3D stacking and advanced pixel-level gating techniques.
• This technology holds promise for next-generation LiDAR systems requiring high accuracy and performance in diverse environments.