DOD/MDA STTR 2011.A 2

OBJECTIVE: This topic seeks to identify and develop high-power Radio Frequency Micro Electro-Mechanical Systems (RF-MEMS) accelerated reliability test methodologies to reduce technology acceptance time for switched phase shifters that utilize capacitive or contact RF MEMS switches. Currently, life testing conducted on RF MEMs switching devices requires significant time and cost due to a lack of physics-based test acceleration methodology. Identification of acceleration protocols, beyond currently conducted real-time life testing approaches, is required to shorten the test time required and accelerate acceptance of these technologies by government programs. The development of an acceptable physics-based model and accelerated test methodology would significantly reduce the cost and time required for system qualification and insertion of high-power RF-MEMS switches and phase shifters for Radar/Electronics Warfare (EW) phased array applications. DESCRIPTION: High power radar and EW modules are required for Electronically Scanned Arrays (ESAs) to provide significant system performance improvements. These modules, from a system perspective, are a major portion of the system cost and they provide thermal and reliability challenges to designers and manufacturers that must be overcome to provide effective ESA solutions. RF MEMS switches and phase shifters have been under development to provide phase control in some ESA architectures. These devices offer the potential of low insertion loss, ultra-linear performance and very low operating power. The qualification and adoption of these technologies by programs requires demonstrated reliability, however current real-time testing is costly because it requires significant time to cycle the RF MEMS switches and phase shifters. R & D efforts are required to identify acceleration mechanisms that allow prediction of device lifetime by means of short-term testing. The goal of this program is to perform the research and development needed to establish RF MEMS device accelerated reliability test methodologies applicable to X-Band (8-12 GHZ) MEMs devices with output power levels of up to 5W peak, 2W average. PHASE I: Identify, model and demonstrate innovative material, design, process and testing methods that lead to accelerated high-power RF MEMs reliability testing. This should include physics-based models, equipment improvements, and test procedure standardization/improvement based on experimental results on capacitive or contact RF MEMS switches that lead to at least a 5X test time reduction over current real-time life test methodologies. PHASE II: Develop and demonstrate a prototype lifetime test methodology for high power RF MEMs switches and phase shifters capable of X-band operation at power levels up to 5W peak, and 2W average that has the test time reduction developed in Phase I. The prototype procedures developed should have dual use/commercial application. PHASE III: Deliver a prototype test station to the government after conducting validation testing of the lifetime of RF MEMs devices having the performance identified in this topic. Transition the test methodologies developed in Phase II to support an MDA system insertion. DUAL USE/COMMERCIALIZATION POTENTIAL: RF MEMS switches and phase shifters are being developed for commercial and military applications, these components are enabling higher performance ESA for EW and Radar, and they would find numerous applications in military systems as well as commercial systems, for example, transportation radar systems. REFERENCES: 1. H. S. Newman, J. L. Ebel, D. Judy, and J. Maciel,"Lifetime Measurements on a High-Reliability RF-MEMS Contact Switch,"IEEE Microwave and Wireless Components Letters, Vol. 18, No. 2, 2008. 2. X. Yuan, Z. Peng, J. C. M. Hwang, D. Forehand, and Charles L. Goldsmith,"Acceleration of Dielectric Charging in RF MEMS Capacitive Switches,"IEEE Transactions on Device and Materials Reliability, Vol. 6, No. 4, 2006. 3. J. Teti, and F. Darreff,"MEMS 2-bit Phase-Shifter Failure Mode and Reliability Considerations for Large X-Band Arrays,"IEEE Trans. Microwave Theory and Tech., Vol. 52, No. 2, pp. 693-701, 2004.

OBJECTIVE: The overall objective of this effort is to develop innovative solutions to significantly decrease the defect and dislocation sizes and densities in large format (>25 cm^2) II-VI compound semiconductor infrared detector materials. Emphasis shall be given to detectors operating in the short through mid-long wavelength regime (~10 micron cut-off). DESCRIPTION: The Missile Defense Agency (MDA) is interested in technology developments in support of advanced space sensor systems. Space-based sensors operate in low background environments where the minimization of noise is paramount to mission operation. Sensor bands from the short through mid-long wavelength infrared (IR) wavelengths are of interest. Large format infrared focal plane arrays based on mercury cadmium telluride (MCT) have been demonstrated at>25 cm^2 with acceptably low levels of defects and dislocations when grown on lattice-matched cadmium zinc telluride (CZT). However, MCT grown on less costly, alternative substrates such as Si exhibit significantly higher numbers of dislocations and defects, despite the use of multiple buffer layers. Dislocations and defects in infrared detector materials are manifested as noise, defective pixels, and current leakage, limiting the FPA operability characteristics. They also propagate with thermal cycling, limiting the service lifetimes of infrared focal plane arrays. These defects and dislocations are highly influenced by non-optimal surface interfaces, with contributing factors such as lattice mismatch, surface roughness, coefficient of thermal expansion mismatch, and the presence of an oxide layer. The Ballistic Missile Defense System (BMDS) requires reliable, high performance, high sensitivity and low noise space-based sensors which are affordable and producible. Atomic hydrogen passivation of substrates prior to epitaxial growth, and/or detector and cap layers prior to passivation may be a viable solution for reducing defects. Innovative methods such as, but not limited to atomic hydrogen etching, are being sought to affordably reduce dislocations and defects in IR detector materials. An offeror may submit multiple proposals with unique approaches. PHASE I: Identify and investigate unique process designs and/or production process changes or additions suitable for IR detector fabrication that will result in a significant reduction in defect and dislocation size and densities, while retaining or enhancing performance and operational lifetimes. Hydrogenation of interfaces has been proposed as a potential concept; other approaches are encouraged. Theoretical and experimental proof-of-concept, including stability of the process during processing and thermal cycling shall be demonstrated and documented. A deliverable detector (discrete or array) or design available to the government for additional characterization is highly desirable. Offerors are strongly encouraged to work with infrared component contractors to help ensure applicability of their efforts and begin work towards technology transition, either by license or service. PHASE II: Using the resulting process, techniques, and/or process changes or additions developed in Phase I, verify and optimize these changes in a prototype fashion, on or off a product line to demonstrate the feasibility and efficacy of the technique. The contractor should keep in mind the goal of commercialization of this innovation for the Phase III effort, to which end they should have working relationships with, and support from, infrared component contractors. PHASE III: Either solely, or in partnership with a suitable production foundry, implement, test and verify in full scale the Phase II demonstration item as an economically viable production technique. Demonstration would include, but not be limited to, demonstration in a real product line with the resulting IR detector / focal plane array testable in a system level test-bed against system performance criteria. This demonstration should show near-term application to BMDS systems, subsystems, or components. DUAL USE/COMMERCIALIZATION POTENTIAL: Innovations developed under this topic will benefit both DoD and commercial space, airborne, and terrestrial programs. Possible uses for these products and techniques include surveillance, astronomy, mapping, weather monitoring, and earth resource monitoring. Enhancements to imaging quality and higher product yields show significant potential for increased applications. REFERENCES: 1. K.S. Ziemer, C.D. Stinespring, L.S. Hirsch, and T.H. Myers,"Characterization of Atomic Hydrogen-Etched HgCdTe Surfaces", Journal of Crystal Growth, Vol. 191, pp. 594-598, 1998. 2. L.S.Hirsch, K.S. Ziemer, M.R. Richards-Babb, C.D. Stinespring, T.H. Myers, and T. Colin,"The Use of Atomic Hydrogen for Low Temperature Oxide Removal from HgCdTe", Journal of Electronic Materials, Vol. 27, No. 6, pp. 651-656, 1998. 3. L.S.Hirsch, Zhonghai Yu, S.L. Buczkowski, and T.H. Myers,"The Use of Atomic Hydrogen for Substrate Cleaning for Subsequent Growth of II-VI Semiconductors", Journal of Electronic Materials, Vol. 26, No. 6, pp. 534-541, 1997.