Reduction in Dark Current in Photodiodes: A Review

Area of Science:

• Optoelectronics and Semiconductor Device Physics
• Materials Science for Photodetection

Background:

• Dark current is a primary noise source in photodiodes, limiting sensitivity in low-light conditions.
• Understanding dark current mechanisms is crucial for advancing photodetector technology.

Purpose of the Study:

• To comprehensively review the physical mechanisms of dark current generation in photodiodes.
• To survey and categorize diverse techniques for mitigating dark current.
• To provide a structured overview of literature relevant to various photodiode applications.

Main Methods:

• Literature review of publications on dark current mechanisms and reduction strategies.
• Categorization of dark current mechanisms: diffusion, SRH, tunneling, and surface leakage.
• Classification of reduction techniques: thermal management, passivation (e.g., ALD Al2O3), guard rings, gettering, doping optimization, and advanced architectures (e.g., pinned photodiodes, black silicon).

Main Results:

• Detailed examination of the physical origins and signatures of different dark current components.
• Systematic organization of reduction strategies applicable across various material systems (Si, Ge, III-V).
• Identification of key findings and material relevance for near-infrared, CMOS imaging, SPADs, and ToF applications.

Conclusions:

• Effective dark current reduction is essential for high-performance photodiodes.
• A variety of physical mechanisms and engineering solutions exist, tailored to specific materials and applications.
• This review consolidates knowledge to guide future photodiode research and development.