TECHNOLOGY AREAS: Electronics

The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), which controls the export and import of defense-related material and services. Offerors must disclose any proposed use of foreign nationals, their country of origin, and what tasks each would accomplish in the statement of work in accordance with section 3.5.b.(7) of the solicitation.

OBJECTIVE: This topic seeks to significantly improve Wide Bandgap (WBG) Device and Component accelerated reliability test methodologies over the current State of the Art. Existing accelerated reliability test equipment utilized at government and contractor facilities have significant limitations in measuring junction temperatures accurately and maintaining accurate test power conditions. The inherent limitations of the test equipment in monitoring the actual junction temperatures of all test devices/components within test runs leads to variability in the reliability data that is obtained. This variability results in large error brackets on obtained test data and on the calculated activation energy values used to predict lifetimes for the device/components. The uncertainty of the junction temperatures and resulting lifetime estimates leads to program insertion risk in fielding high power WBG device/component technologies; it also leads to increased system logistics costs. Current life test stations have limited to no error bracket data available on reliability test data being generated and lifetime prediction uncertainty. This project would seek to understand current system error brackets and data limitations and to define innovatiive equipment and test protocols to significantly improve accelerated RF WBG life testing and reliability predictions.

DESCRIPTION: High power radar and EW modules are required for Electronically Scanned Arrays (ESA) 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 over come to provide effective ESA solutions.

The state of the art for Wide BandGap(WBG) device/component reliability testing and device life predication is currently limited by the accuracy that the device/component junction temperatures can be determined, monitored and controlled during accelerated life stress tests, The intrinsically robust nature of the WBG device materials makes accelerated testing using traditional test equipment and test methods more difficult and test time durations that are costly. The robust nature of wide bandgap materials requires testing to be conducted at higher temperatures to accelerate failure mechanisms to occur within realistic test times. The higher thermal conductivity of the WBG materials also makes junction temperature measurement within the complex fixturing required for RF stress testing difficult. Typically, temperature monitoring and measurement are taken at known locations on the device/component test assembly and junction temperatures are calculated from this known temperature reading using computer models that extrapolate to obtain the actual junction temperature. This leads to large error brackets on the obtained junction temperature data, errors in prediction of activation energies and extrapolated Arrhenius life times. System impacts from these test/data limitations and errors can lead to significantly higher cost systems, logistics and reliability issues as well.

The above issues, lead to significant reliability test data error-brackets and variability in life time predictions. Innovative technologies are sought that 1) improve accelerated life test equipment and fixturing with increased test range (higher temperatures >400 C), and 2) improve junction temperature identification through in situ measurement, measurement/modeling procedure standardization and or methodologies to increase reliability test data range and extrapolation are sought. It will be important that any proposed solution shall significantly improve the state of the art for WBG reliability tests and that lifetime prediction data error brackets be minimized.

PHASE I: Identify, model and demonstrate innovative material, design, process and testing technologies that significantly improve reliability test equipment performance range and accuracy. This should include equipment improvements, test procedure standardization/improvement and/or improved device junction temperature measurement or calculation.

PHASE II: Develop and demonstrate a prototype test station and test procedures for high power wide bandgap devices/components of interest to the government, and deliver a prototype test station to the government. The prototype equipment and processes developed should have dual use application and commercial applications.

PHASE III: Transition developed technologies, utilize technology developed on transition system insertion modules and demonstrate performance, reliability and cost benefits shall be identified.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: Wide Bandgap semiconductors are being developed for commercial and military RF and power 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 transportation radar systems.

REFERENCES:
1. "DARPA Wide-Band-Gap Semiconductors for rf Applications (WBGS-RF) Tri-Service Reliability Testing", S. C. Binari and J. Roussos Naval Research Laboratory, Washington, DC; G. D. Via Air Force Research Laboratory, Dayton, OH; E. Viveiros Army Research Laboratory, Adelphi, MD, presented at GOMACTech-06.

2. www.darpa.mil/MTO/Programs/wbgsrf/pdf/RFIC.pdf

3. www.gaasmantech.org/Digests/2005/2005papers/1.2.pdf

KEYWORDS: ESA; Radar;EW;Bandgap; Accelerated Test; Reliability

** TOPIC AUTHOR (TPOC) **

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