Chang Chiao, Li Hui, Ku Chien-Te, Yang Shih-Guo, Cheng Hung Hsiang, Hendrickson Joshua, Soref Richard A, Sun Greg
Appl Opt. 2016 Dec 20;55(36):10170-10173. doi: 10.1364/AO.55.010170.
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/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.
我们报告了一种基于GeSn的320×256图像传感器焦平面阵列的实验性制造和测试，该阵列在-15°C下于1.6 - 1.9μm光谱范围内工作。为了进行图像读出，将Ge/GeSn/Ge p-i-n异质结光电二极管的二维像素阵列倒装芯片键合到定制的硅CMOS读出集成电路上。所得的相机芯片采用背照式操作。成功实现了对钨丝灯泡的成像，观察到了使用可见光相机无法看到的灰度“热点”红外特征。在未来的测试中，本成像阵列中使用的锗晶片将被硅基锗晶片取代，这种晶片在硅或SiO/Si上提供薄膜锗。这有望提高背照式操作中获得的红外响应度，并将使基于硅的代工厂能够制造成像器。我们的实验朝着实现IV族近中红外成像系统（如用于夜视的系统）迈出了重要一步。
