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Advanced Heat Spreader Technology for Gallium Nitride (GaN) Monolithic Microwave Integrated Circuits (MMICs)
Navy SBIR 2016.1 - Topic N161-052 NAVSEA - Mr. Dean Putnam - dean.r.putnam@navy.mil Opens: January 11, 2016 - Closes: February 17, 2016 N161-052 TITLE: Advanced Heat Spreader Technology for Gallium Nitride (GaN) Monolithic Microwave Integrated Circuits (MMICs) TECHNOLOGY AREA(S): Battlespace, Electronics, Sensors ACQUISITION PROGRAM: PEO IWS 2.0, Air and Missile Defense Radar (AMDR) The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with section 5.4.c.(8) of the solicitation. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws. OBJECTIVE: Develop an innovative, low-cost Monolithic Microwave Integrated Circuits (MMICs) heat spreader technology for high-power density GaN microwave power amplifiers. DESCRIPTION: Future Navy radar and electronic warfare (EW) systems will be based on transmit and receive (T/R) module architectures where dozens (perhaps hundreds) of T/R modules are packed tightly behind the array face. Typically, each individual module contains multiple MMIC high-power amplifiers (HPAs), with GaN on silicon carbide (SiC) being the current state-of-the-art. The future trend is toward increasing levels of power density within the T/R module. This is a natural consequence of the constant need to increase radar and EW transmitted power in order to keep pace with emerging threats. However, the trend toward increasing power density results from the desire for higher levels of integration in order to reduce size and weight. The performance and reliability of GaN transistors are fundamentally tied to operating temperature, and amplifiers of higher efficiency naturally generate less waste heat. The efficiency of GaN HPAs has increased remarkably over the past twenty years. However, the potential for further increases in efficiency is limited and efficiency alone cannot be the predominant enabler of the higher power densities required by future systems. Consequently, the operating temperature of the HPA MMIC (specifically the transistor gate region) will be the limiting factor in system design and thermal management will be an integral issue in HPA MMIC design for T/R module applications (Ref. 1). A number of previous efforts have addressed T/R module packaging and thermal management at the macro scale - that is, the problem of removing heat from the overall MMIC structure to the T/R module housing, and finally to structural support members which incorporate liquid cooling. However, for radar systems requiring long pulse operation (at pulse widths of 5 ms or greater) or EW systems that require high duty cycle operation (typically exceeding 10%), the dissipation of heat at the location of the transistors themselves becomes the limiting factor in thermal management. At the MMIC level, various solutions have been investigated with the simple substitution of highly conductive materials, such as diamond, being the most straightforward (Ref. 2). However, even highly conductive layers have not yielded the performance required and are compromised by the thermal conductivity of the epoxy or solder used to bond to the MMIC (Ref. 3 and 4). Consequently, an advanced heat spreader technology (materials, design, and bonding method) that offers a significant improvement in heat dissipation at the MMIC level (at the MMIC-bond interface) is desired. An order of magnitude improvement in heat conduction represents the ideal goal. Significant restrictions, arising from performance, reliability, sustainability, and affordability considerations, complicate the requirements for new heat spreader technology. First among these is that the proposed technology must be compatible with existing GaN on SiC MMIC technology and existing HPA designs. This enables transition of the technology to near-future Navy systems such as the Air and Missile Defense Radar (AMDR) in the form of technology updates without requiring fundamental system architecture changes while also benefiting future designs. Another requirement is that the heat spreader technology should not depend on an external supply of liquid cooling to the T/R module as this represents a minority of system architectures. Reliability is a paramount concern and proposed technologies must have reliable life expectancies exceeding the GaN MMICs they support (a minimum T/R module service life of 15 years can be assumed). Finally, affordability is a prime concern. Proposed technologies must be compatible with automated assembly processes and the intrinsic materials must have a path toward manufacturability in production volumes. Ideally, the material cost of the heat spreader technology, will increase the overall MMIC assembly cost by no more than 10%. This topic serves to enable higher transmitted power from future versions of AMDR without requiring a major system change. Increased transmit power improves fundamental radar performance parameters such as detection range. If this can be done without increasing the radar size and without changing the radar architecture, the increased performance can be had at a fraction of the cost. By addressing the fundamental thermal management problem that limits HPA MMIC performance, increased power can be obtained from essentially the same T/R module design. The technology sought by this topic is widely applicable and the same arguments are equally true for future EW systems such as the Surface Electronic Warfare Improvement Program (SEWIP). PHASE I: The company will develop a concept for advanced heat spreader technology at the GaN HPA MMIC level that meets the requirements stated in the topic description. The company will demonstrate the feasibility of their concept in meeting Navy needs and will establish that the concept can be feasibly produced by sample testing, modeling, simulation, and analysis. The company will address technical risk reduction and provide performance goals and key technical milestones. Phase I Option, if awarded, would include the initial layout and capabilities description to develop the advanced heat spreader material with the associated bonding process in Phase II. PHASE II: Based on the results of Phase I and the Phase II Statement of Work (SOW), the company will develop a prototype heat spreader technology and the associated processes for bonding GaN HPA MMICs to the heat spreader. The prototype material with associated bonding process will be evaluated to determine its capability in meeting the performance goals defined in Phase II SOW and the Navy requirements for thermal management of HPA GaN MMICs in T/R modules. Performance will be demonstrated through the company’s laboratory testing of prototypes under simulated operational conditions. Performance must be verified over the required range of parameters including numerous thermal cycles. However, prototype testing may be augmented by modeling and analytical methods. Evaluation results will be used to refine the prototype into an initial design to meet state-of-the- art performance in a T/R module application for a military grade system and that will meet Navy requirements. The company will deliver the prototype at the end of the Phase II. The company will prepare a Phase III development plan to transition the technology for commercial use to supply Navy needs. PHASE III DUAL USE APPLICATIONS: The company will be expected to produce its heat spreader technology and support the processes required for its successful transition into Navy use in programs such as AMDR. The company will develop and fully document the processes required to deploy the technology for use by industry according to the Phase III development plan. The technology will be evaluated to determine its effectiveness in full-rate production of T/R Modules based on GaN MMIC HPAs. The US domestic radio frequency (RF) semiconductor business supplies commercial as well as military markets and advances in semiconductor and MMIC technology, though first implemented in military systems, eventually transition to commercial product lines. Since this topic seeks to develop a product for MMIC thermal management and not a specific military application, the potential for commercial application is unfettered. The potential commercial market is essentially unlimited should the technology prove cost competitive. REFERENCES: 1. Kopp, Bruce A., et al. "Transmit/Receive Modules." IEEE Trans. Microwave Theory and Techniques 50 March 2002: pp. 827-834. 2. Bar-Cohen, Avram, et al. "Near-Junction Thermal Management for Wide Bandgap Devices." 2011 IEEE Compound Semiconductor Integrated Circuit Symposium (CSICS), Waikoloa, HI, Oct 16-19 2011: 1-5. 3. Margomenos, A., et al. "Novel Packaging, Cooling and Interconnection method for GaN High Performance Power Amplifiers and GaN Based RF Front-Ends." Proc. 42nd European Microwave Conf., Amsterdam, Oct. 29 - Nov. 1 2012: pp. 995-998. 4. Zhao, Yuan, et al. "Advanced Packaging and Thermal Management for High Power Density GaN Devices." 2013 IEEE Compound Semiconductor Integrated Circuit Symposium (CSICS), Monterey, CA, Oct 13-16 2013: 1-4. KEYWORDS: Heat spreader for MMICs; thermal management in radar systems; T/R module; GaN MMIC; GaN HPA; GaN on SiC TPOC-1: Lawrence Dressman Phone: 812-854-4804 Email: lawrence.dressman@navy.mil TPOC-2: Brian Olson Phone: 812-854-6385 Email: brian.d.olson1@navy.mil Questions may also be submitted through DoD SBIR/STTR SITIS website.
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