Dual-Mode, Extended Near-Infrared, Focal Plane Arrays Fabricated with CMOS Compatible GeSiSn Alloy Materials

The main thrust of this Phase II program is to ultimately generate good quality 2.2 micron photodiode stacks on silicon platforms and optimize the materials properties for fabrication of detector arrays of interest to DARPA. The material stacks involve synthesis and characterization of Ge1-ySny semiconductors (y= 5.5-6.5 %) in PIN geometry. The work will initially emphasize diodes containing at least only one defected interface. This represents an improvement to the state of the art. The homo-structure approach may be implemented in the second year of the project to enhance the emission efficiency if required. In the third year of the project, the materials science technology will be stationed in years to a large area 4 inch wafers for delivery to Freedom Photonics. An additional photodiode design that is of interest is a separate-absorption-charge-multiplication APD type. The effort in this case is secondary and the goal is to get one device (or small array (3x3 or 4x4)) operational by year 3.