Related Experiment Video
Updated: Jan 17, 2026
06:53
Photoelectron Imaging of Anions Illustrated by 310 Nm Detachment of F−
Published on: July 27, 2018
9.1K
InAlAs digital alloy avalanche photodiode with partially depleted absorber
Optics Letters
|September 16, 2025
Summary
This study introduces a novel avalanche photodiode (APD) design using a partially depleted absorber and flip-chip bonding. The enhanced APD achieves a 22 GHz bandwidth and 40 Gbps data rate, significantly improving optical communication performance.
Area of Science:
- Optoelectronics
- Semiconductor Devices
- Photonics
Background:
- Digital alloy (DA) InAlAs was previously used in separate absorption, grading, charge, and multiplication (SAGCM) avalanche photodiodes (APDs) to reduce noise.
- High-speed optical communication demands improved avalanche photodiode (APD) performance in terms of bandwidth and quantum efficiency.
Purpose of the Study:
- To enhance the bandwidth and quantum efficiency of SAGCM APDs.
- To improve the response speed of APDs for high-speed data transmission.
Main Methods:
- Incorporation of a partially depleted absorber (PDA) to increase bandwidth.
- Utilization of a back-illumination structure with flip-chip bonding for enhanced quantum efficiency and inductive peaking.
- Characterization of dark current density, multiplication gain, responsivity, and frequency response.
Main Results:
- The APD achieved a dark current density of 8.5 mA/cm² at 90% breakdown voltage.
- A multiplication gain of 50 was observed before avalanche breakdown, with a responsivity of 0.49 A/W.
- Flip-chip bonding increased the bandwidth from 15.6 GHz to 22 GHz, enabling eye diagrams up to 40 Gbps.
Conclusions:
- The developed APD with a PDA and flip-chip bonding demonstrates significantly improved high-speed performance.
- This design is suitable for next-generation optical communication systems requiring high bandwidth and data rates.
