Simulation-Based Design of a Silicon SPAD with Dead-Space-Aware Avalanche Region for Picosecond-Resolved Detection

Area of Science:

• Photonics and Semiconductor Devices
• Quantum Optics and Information

Background:

• Single-photon avalanche diodes (SPADs) are crucial for sensitive light detection.
• Optimizing SPADs for faster response and improved breakdown characteristics is essential for advanced applications.

Purpose of the Study:

• To design and simulate an optimized silicon SPAD for picosecond-resolved photon detection.
• To enhance electric field confinement and suppress edge breakdown using novel structural and doping strategies.

Main Methods:

• Utilized COMSOL Multiphysics for device simulation.
• Implemented a dead-space-aware impact ionization model to capture avalanche behavior.
• Incorporated a guard ring structure and tailored doping profiles.

Main Results:

• Achieved sub-20 ps response time with a FWHM of ~17.8 ps.
• Demonstrated enhanced breakdown localization and reduced gain sensitivity compared to conventional designs.
• Confirmed stable gain slope and consistent avalanche triggering across bias voltages.

Conclusions:

• The optimized silicon SPAD design shows significant improvements in timing resolution and device stability.
• The proposed SPAD is suitable for next-generation quantum imaging, LiDAR, and optical communication systems.
• Simulation-based design with advanced models is effective for optimizing SPAD performance.