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High-performance waveguide coupled Germanium-on-silicon single-photon avalanche diode with independently controllable
Heqing Wang1, Yang Shi2, Yan Zuo2
1Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
Nanophotonics (Berlin, Germany)
|December 16, 2024
Summary
We developed a new three-terminal Germanium-on-silicon (Ge-on-Si) single photon avalanche diode (SPAD). This device achieves high single photon detection efficiency and low dark counts, ideal for quantum communication and lidar applications.
Area of Science:
- Photonics and Optoelectronics
- Semiconductor Devices
- Quantum Technologies
Background:
- Germanium-on-silicon (Ge-on-Si) single photon avalanche diodes (SPADs) are crucial for integrating photonics with silicon.
- Conventional SPADs face limitations in optimizing carrier dynamics and doping profiles.
- There is a need for improved Ge-on-Si SPADs with enhanced performance and reduced dark counts.
Purpose of the Study:
- To propose and demonstrate a novel three-terminal waveguide-coupled Ge-on-Si SPAD.
- To optimize carrier drift and multiplication independently through separate voltage control.
- To reduce dark counts without compromising detection efficiency.
Main Methods:
- Fabrication of a three-terminal Ge-on-Si separate-absorption-charge-multiplication SPAD.
- Independent voltage control of absorption and multiplication regions.
- Characterization of device performance, including detection efficiency, dark counts, and noise equivalent power.
Main Results:
- Achieved a high on-chip single photon detection efficiency of 34.62% at 1310 nm.
- Recorded low dark count rates of 279 kHz at 78 K.
- Obtained a noise equivalent power of 3.27 × 10⁻¹⁶ WHz⁻¹/².
- Demonstrated the lowest noise equivalent power among reported waveguide-coupled Ge-on-Si SPADs.
Conclusions:
- The three-terminal SPAD design enables separate optimization of absorption and multiplication regions.
- Reduced electric fields on sidewalls significantly lower dark counts.
- The device offers high performance, robust operation, and potential for high-yield fabrication.
- Promising applications in on-chip quantum communication and lidar systems.
