SWIR Image Sensor Based on SiGe Nanomembranes

ABSTRACT: With a cutoff at 1.6 & #956;m, high carrier mobility, and the potential to be integrated with silicon integrated circuits, Ge offers the possibility to achieve large size arrays and small pixel pitch for high sensitivity SWIR imaging near room temperatures. In addition, integrating SWIR image sensors on flexible substrates opens new applications and opportunities for night vision systems such as tunable visual fields by bending the array of photodiodes into different curvatures and shapes. In this program, Agiltron, Inc. and the University of Wisconsin-Madison propose to develop the first curved SWIR image sensor. The sensor is based on the integration of single-crystalline Si and Ge nanomembranes. This has the potential to achieve high quality Ge-on-Si photodiodes for SWIR imaging on flexible substrates. The photodiode fabrication does not require any epitaxy step which removes significant development costs. BENEFIT: This program addresses the lack of SWIR image sensors with array sizes larger than 1K1K and pixel pitch smaller than 10 & #956;m. Increasing the resolution and sensitivity in SWIR imaging is critical for night-vision applications such as driver vision enhancement and Intelligence, Surveillance and Reconnaissance (ISR) military and security systems. In addition, integrating the image sensor and the CMOS read-out IC results in a lower cost SWIR system that can be more extensively deployed in the field. Finally, developing sensing and imaging technology on flexible substrates is of great interest for the DoD as it opens new applications such as a tunable field of view and increase the system integration capabilities. This will enable high-performance imagers with a small form factor and field of view that far exceeds the state of the art possible with planar focal plane arrays.