Improved performance of small pixel infrared detector focal plane arrays via in situ mesa sidewall characterization.

Advanced infrared imaging (night vision) equipment forms a critical component of the US military's tactical capabilities. The development of new third-generation, multi-wavelength infrared focal-plane arrays (FPAs) promises to enhance the superiority of the US military by providing improved target discrimination and identification, along with enhanced resolution. These developments require the use of new materials technologies for detector fabrication, such as type-II strained-layer superlattice detectors. A major obstacle to realizing the full performance advantage of these new materials is the need to passivate pixel side-walls for the suppression of defect-induced dark currents and associated noise. Existing characterization techniques are insufficient to gain important information on side-wall morphology and chemistry to rapidly assess passivation techniques for effectiveness and reliability. Therefore, ACTOPROBE LLC seeks funding to develop an innovative, combined atomic-force/tip-enhanced Raman spectroscopy instrument for this type of characterization, making use of advanced, specially fabricated scanning probes that can probe steep side-walls (>80 deg.) within confined trenches (10 micron depth). Prototypes of the probes have been fabricated and are currently being tested. This new instrument will enable high-resolution, non-destructive chemical and morphological analysis, as well as electrical measurements (capacitance voltage profiling), thereby providing timely feedback to optimize detector passivation and processing.