2×128 Silicon Avalanche Photodiode Linear Arrays with High Uniformity

In this letter, we report a high-uniformity 2×128 silicon avalanche photodiode linear array for 3D imaging. The 100 μm diameter, 50 μm 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.