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Substrate materials to grow single crystal quality Magnetic films by Liquid Phase Epitaxy (LPE)

Description:

TECHNOLOGY AREA(S): Electronics 

OBJECTIVE: New analog radio-frequency (RF) signal processing and enhanced electromagnetic (EM) interference mitigation capabilities afforded by devices based on high-quality magnetic materials are desired for existing and future military communications, signal intelligence (SIGINT), electronic warfare (EW), and radar systems. This topic seeks the development of an industrial domestic manufacturing capability for high quality Yttrium Iron Garnet Films (YIG) films to use in the production of Frequency Selective Limiters (FSLs) that are tunable to different frequency ranges. Of particular interest is the Seed substrate on which the epitaxial magnetic film is grown. 

DESCRIPTION: The number of systems relying on the use of the EM spectrum is increasing rapidly, in both military and commercial sectors. The rising spectral congestion is placing increasingly challenging requirements on the performance of components and modules that comprise the RF front-ends of communications, radar, and electronic warfare (EW) systems. Magnetic components, such as filters, phase shifters, delay lines, baluns, circulators, and isolators, among others, offer low insertion loss, high power handling capability, and low power consumption needed to improve the performance and reduce size, weight, power, and cost (SWaP-C) of these systems. In recent years, the use of single-crystal quality magnetic materials has resulted in significant performance improvements, as well as enabled new analog RF signal processing functionality, such as frequency-selective limiting (FSL) and signal-to-noise enhancement (SNE) devices. 

PHASE I: Demonstrate the synthesis of single-crystal quality magnetic substrates in 2 inch diameter or 1.5 by 1.5 inch square form factor. The thickness of the magnetic layer has to be at least 10 micrometers. Demonstrate ferrimagnetic resonance linewidth, delta-H, of <1 Oersted and spinwave linewidth, delta-Hk, of <0.2 Oersted. The thickness of the magnetic layer has to be uniform to within 3% over the entire area of the substrate. The density of dislocations has to be below 1 per square centimeter over an area covering at least 80% of the surface. 

PHASE II: Extend the single-crystal quality magnetic substrates synthesis technique to other magnetic material compositions to enable analog signal processing device applications 0.3 to 30 GHz. Demonstrate the synthesis of single-crystal quality magnetic substrates in 4 inch diameter or 3 by 3 inch square form factor. Demonstrate capability to produce magnetic layer thicknesses from 10 nm to 100 micrometers. Make a lot of 10 substrates available for verification testing to demonstrate quality, consistency and reproducibility. 

PHASE III: Develop and characterize an industrial grade synthesis process with >90% yield and production rate of no more than 4 hours per substrate per process line. Develop a manufacturing plan and production cost reduction plan. Produce at least 100 substrates and gather and analyze statistics on defects, uniformity, and repeatability. Make a lot of 10 substrates and 10 devices available for verification testing to demonstrate quality, consistency and reproducibility. 

REFERENCES: 

1: J. D. Adam, "Mitigate the Interference: Nonlinear Frequency Selective Ferrite Devices," in IEEE Microwave Magazine, vol. 15, no. 6, pp. 45-56, Sept.-Oct. 2014.

2:  H.L. Glass, "Growth of thick single-crystal layers of yttrium iron garnet by liquid phase epitaxy", Journal of Crystal Growth, Volume 33, Issue 1, 1976, Pages 183-184, ISSN 0022-0248,

3:  H.L. Glass, M.T. Elliot, "Attainment of the intrinsic FMR linewidth in yttrium iron garnet films grown by liquid phase epitaxy", Journal of Crystal Growth, Volume 34, Issue 2, 1976, Pages 285-288

4:  P.J. Besser, J.E. Mee, H.L. Glass, D.M. Heinz, S.B. Austerman, P.E. Elkins, T.N. Hamilton and E.C. Whitcomb, AIP Conf. Proc. No. 5 (1972) 125.

KEYWORDS: Magnetic Substrate, Spinwaves, Radio-frequency, Analog Signal Processing 

CONTACT(S): 

Hunter Patterson 

(256) 876-4073 

hunter.s.patterson2.civ@mail.mil 

Robert Herron 

(256) 876-5061 

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