2 × 128 Silicon Avalanche Photodiode Linear Arrays With High Uniformity

• Published in: IEEE photonics technology letters 2024-05, Vol.36 (10), p.645-648
• Main Authors: Wang, Tiancai, Peng, Hongling, Cao, Peng, Song, Chunxu, Zheng, Wanhua
• Format: Article
• Language: English
• Subjects: Absorption; Avalanche diodes; Breakdown; Current measurement; Current voltage characteristics; Dark current; Diameters; linear array; Linear arrays; linear mode; Photodiodes; Pixels; Quantum efficiency; Room temperature; Silicon; Silicon avalanche photodiode; Single-photon avalanche diodes; Temperature measurement; Three dimensional imaging; Voltage measurement
• ISSN: 1041-1135; 1941-0174
• DOI: 10.1109/LPT.2024.3384486

In this letter, we report a high-uniformity 2\times 128 silicon avalanche photodiode linear array for 3D imaging. The 100~\mu \text{m} diameter, 50~\mu \text{m} gap pixels incorporate floated guard ring and edge implantation to prevent premature breakdown. Despite the large scale, breakdown voltage uniformity across all 256 pixels exceeds 98.8%. At room temperature, pixels show 0.55 A/W peak responsivity at gain =1 (80% external quantum efficiency at 875 nm) and maximum gain exceeds 550 at 95% breakdown voltage. The array exhibits a 1.6 V deviation in breakdown voltages from 122.8~126 V across pixels, indicating a high uniformity larger than 98.8%. Dark current remains below 60 pA at gain =1 and 300 pA at 90% breakdown voltage per pixel. The capacitance is below 0.4 pF near avalanche. Furthermore, we measured the dark current-voltage characteristic at various temperatures, and a consistently low dark current, at approximately 10 nA, was obtained at a temperature up to 100 °C. These results represent a significant advance for silicon linear arrays in 3D imaging.