Open AccessGe_0975Sn_0025 320 × 256 imager chip for 16–19 μm infrared vision
Author(s) -
CheCheng Chang,
Hui Li,
Chien-Te Ku,
S.-Y. Yang,
Hao-Tien Cheng,
Joshua R. Hendrickson,
Richard A. Soref,
Greg Sun
Publication year - 2016
Publication title -
applied optics
Language(s) - Uncategorized
Resource type - Journals
ISSN - 0003-6935
DOI - 10.1364/ao.55.010170
Subject(s) - optics , responsivity , materials science , image sensor , optoelectronics , wafer , infrared , silicon , microlens , dot pitch , chip , pixel , photodetector , physics , lens (geology) , computer science , telecommunications
We report the experimental fabrication and testing of a GeSn-based 320×256 image sensor focal plane array operating at -15°C in the 1.6-1.9 μm spectral range. For image readout, the 2D pixel array of Ge/GeSn/Ge p-i-n heterophotodiodes was flip-chip bonded to a customized silicon CMOS readout integrated circuit. The resulting camera chip was operated using back-side illumination. Successful imaging of a tungsten-filament light bulb was attained with observation of gray-scale "hot spot" infrared features not seen using a visible-light camera. The Ge wafer used in the present imaging array will be replaced in future tests by a germanium-on-silicon wafer offering thin-film Ge upon Si or on SiO 2 /Si. This is expected to increase the infrared responsivity obtained in back-side illumination, and it will allow an imager in a Si-based foundry to be manufactured. Our experiments are a significant step toward the realization of group IV near-mid-infrared imaging systems, such as those for night vision.