Three-electrode germanium-on-silicon avalanche photodiode array
Xiaobin Liu, Xuetong Li, Zihao Zhi, Yingzhi Li, Baisong Chen, Qijie Xie, Quanxin Na, Xueyan Li, Pengfei Guo, Fengli Gao, Guo‐Qiang Lo, Bonan Kang, Junfeng Song
Abstract
In this Letter, we report a bridge-connected three-electrode germanium-on-silicon (Ge-on-Si) avalanche photodiode (APD) array compatible with the complementary metal-oxide semiconductor (CMOS) process. In addition to the two electrodes on the Si substrate, a third electrode is designed for Ge. A single three-electrode APD was tested and analyzed. By applying a positive voltage on the Ge electrode, the dark current of the device can be reduced, and yet the response of the device can be increased. Under a dark current of 100 nA, as the voltage on Ge increases from 0 V to 15 V, the light responsivity is increased from 0.6 A/W to 1.17 A/W. We report, for the first time to the best of our knowledge, the near-infrared imaging properties of an array of three-electrode Ge-on-Si APDs. Experiments show that the device can be used for LiDAR imaging and low-light detection.