Focus Center Research Program and Raytheon
The Focus Center Research Program, sponsored by the Defense Advanced Research Projects Agency (DARPA) and the Semiconductor Industry Association, is a university research consortium originally established to perform research to extend silicon CMOS (complementary metal oxide semiconductor) to its ultimate limits — keeping the United States and its industries at the forefront of microelectronics technology. Raytheon joined the FCRP in 2009. Since then, the FCRP mission has evolved and now includes exploration of new material systems and devices to extend and enhance CMOS technology, as well as explore circuit, subsystems and systems architectures enabled by the advancements in device and material technologies. The FCRP consists of six centers covering research ranging from fundamental electronic materials and device physics through multiscale systems (Figure 1). Each center is led by a world renowned researcher and staffed by faculty experts from multiple universities. The six centers and their mission statements are:
- 1. FENA (Functional Engineered Nano-Architronics): Create and investigate new nano-engineered functional materials and devices, and novel structural and computational architectures for new information processing systems and sensors beyond the limits of conventional CMOS technology.
- 2. MSD (Materials, Structures and Devices): Explore paths that overcome the limits of Si CMOS scaling in the continuing evolution of electronics through CMOS-extension: new device materials, structures and operating principles to overcome power-performance limitations of scaled transistors in future CMOS circuits; and CMOS Plus: system performance enhancement and functional diversification pursued via heterogeneous device integration with CMOS.
- 3. IFC (Interconnect Focus Center): Discover and invent new electrical, optical, wireless and thermal connectivity solutions (create new technological options) that will meet or exceed semiconductor technology road map projections and enable hyper-integration of heterogeneous components for future tera-scale systems.
- 4. C2S2 (Center for Circuit and System Solutions): Invent and demonstrate the circuit-level topologies and design techniques necessary to deliver working designs from a base platform that includes scaled devices that are increasingly difficult to predict and control, as well as other devices that may be non-scalable but bring additional functionality.
- 5. GSRC (GigaScale Research Center): Address the research challenges in the design (hardware and software) and utilization (programming and interfacing) of information system platforms for consumer/enterprise/defense applications, to be deployed in the late- and post-silicon era, so as to achieve orders of magnitude improvement in cost (design and related non-recurring engineering, programming) and quality (lower power, higher functional performance, increased reliability, increased usability).
- 6. MuSyC (Multiscale System Research Center): Create comprehensive and systematic solutions to the distributed multi-scale system design challenge, including development of “energy-smart” distributed systems that are deeply aware of the balance between energy availability and demand, and adjust behavior through dynamic and adaptive optimization through all scales of design hierarchy.
Each center is performing research of direct relevance to the future needs of the five major Raytheon businesses.
Since Raytheon joined the FCRP there have been a wide range of interactions between FCRP faculty and students and Raytheon staff. This includes participation in center annual reviews, attendance at weekly e-seminars, and more importantly, one-on-one meetings with faculty (both at Raytheon and at the universities) in order to leverage FCRP research to meet Raytheon needs as well as pursue contract research and development opportunities. The following are some examples of FCRP research that is aligned with Raytheon near- and long-term needs.
The FCRP has a large, multidisiplinary effort exploring the unique electronic and thermal properties of carbon (either carbon nano-tubes or graphene) for use as digital and analog/RF devices, thermal interface materials, transparent electrodes, interconnects and energy storage. For example, Prof. Alexander Balandin of the University of California, Riverside, is investigating novel RF circuits based on graphene transistors for frequency doublers, RF mixers and phase detectors (Figure 2). Prof. Bruce Dunn of UCLA is researching carbon nanotube-based electrodes and sol-gel electrolytes to create high-density capacitors that can be directly integrated onto semiconductor chips. This technology would provide on-chip energy storage and lead to more compact, lightweight multichip assemblies for use in transceivers and imaging focal plane arrays.
THz Quantum Cascade Lasers
Raytheon is working with Prof. Ben Williams of UCLA to develop concepts for THz imaging at atmospheric transmission windows in the 1–5 THz frequency range suitable for explosive detection. This work is based on the FENA (Functional Engineered Nano Architectonics) developed quantum cascade lasers (QCL) fabricated from GaAs (gallium arsenide) with a standard SMB (silicon microbolometer) camera. Near-term development would combine advanced GaAs QCLs with higher power, operating close to the 1.5 THz window, with optimized uncooled SMB imaging arrays using an optimized absorbing antenna. The longer-term plan is to exploit advanced gallium nitride (GaN) materials technology developed at Raytheon to increase power and laser operating temperatures.
On-chip High Q Resonators for On-chip Filters
Prof. Dana Weinstein of MIT is performing research on semiconductor-based bulk acoustic wave (BAW) resonators that can be realized as part of the device/circuit fabrication process. The work is currently on silicon-based structures. These are inherently small (transistor size) structures known as resonant body transistors (RBTs) (Figure 3) that can be arrayed to form filter banks. Raytheon has begun work with Prof. Weinstein to extend this work to GaN, which from simulations is a better material due to its strong piezoelectric properties (again leveraging Raytheon’s GaN technology). The long-term objective is to exploit these devices to develop tunable filters/reconfigurable circuits. Long-term, on-chip resonators/filters would be of benefit to a wide range of Raytheon systems (for example Digital Receiver Exciter (DREX) and Intermediate Frequency chains are limited by the size of existing filter technology).
Low Loss Passive Components and 3D Integration
Prof. Paul Kohl of Georgia Tech is performing research on novel materials to create “air cavities” in multilayer dielectric structures. This will enable Raytheon to create compact multi-layer structures without dielectrically loading RF transistors, transmission lines and passive components and it creates a path to compact (3D) RF and mixed-signal circuits. Raytheon has been interacting with Prof. Kohl to integrate and characterize these “ultra-low” k dielectrics into monolithic microwave integrated circuit (MMIC) structures for transceivers.
Compact (on-chip) Power Conditioning Circuits
Prof. Dave Perrault of MIT is leading a team of researchers on the development of components and circuits for compact, high-efficiency power supplies. This research includes Si IC compatible, nano-composite magnetic materials for inductors and transformers, novel high Q (>100) toroidal structures (Prof. Charles Sullivan at Dartmouth), and high temperature/high frequency/high efficiency GaN switching transistors integrated with Si CMOS (Prof. Tomas Palacios at MIT). We have recently partnered with Prof. Palacios on a successful DARPA program for GaN–Si CMOS integration for transceiver applications.
Prof. Manos Tentzeris of Georgia Tech is developing ink-jet-printable, high-gain antennas on flexible substrates (including paper!) with good performance up to 150 GHz (Figure 4). This research offers great potential to Raytheon for conformal arrays and “wearable” electronics.
Novel Circuit Concepts
Another group of faculty is investigating novel Si CMOS-based circuit architectures for cognitive radios. These include: architectures for low-power-spectrum sensing (Prof. Borivoje Nikolic of UC Berkeley and Prof. Ramesh Harjani of the University of Minnesota); adjacent channel rejection (Prof. Asad Abidi of UCLA); wideband tunable receiver front-end (Prof. Nikolic of UC Berkeley); flexible digital baseband (Prof. Dejan Markovic of UCLA); and UWB Transceivers for Ranging & Localization (Prof. Jeyanandh Paramesh of Carnegie Mellon University).
Frequency sources are a key building block in all RF systems. Prof. Ehsan Afshari of Cornell is developing novel, Si CMOS-based, traveling wave circuits to achieve harmonic power generation/combining at millimeter wave and submillimeter frequencies (Figure 5). We have initiated collaboration with Prof. Afshari to develop a GaN version of his oscillator design to provide higher power and dynamic range, once again exploiting Raytheon’s advanced GaN technology.
Research is also being performed in self-verifying/self-healing circuit architectures by Profs. Larry Pileggi and Gary Fedder of Carnegie Mellon University; and in self synthesizing converter circuits by Prof. Michael Flynn of the University of Michigan. These types of circuits and algorithms are key building blocks for “intelligent ICs” that can self-adapt to their mission and self-compensate for environmental factors such as temperature and, as a result, can have a large impact on future Raytheon systems.
Wireless Interconnects (body area networks)
A group of faculty led by Prof. Anantha Chandrakasan of MIT is developing components, circuit architectures and secure data transmission techniques/algorithms to enable “wireless” body area networks (BAN). The team has a rather impressive test-bed demo that simulates a BAN monitoring heart rate and securely transmitting the data. While their immediate objective is for “remote” health care monitoring and medical diagnostics, this research has direct applicability to distributed wireless sensor networks.
Model Based Systems Engineering and Distributed Sense and Control Systems
Prof. Alberto Sangiovanni-Vincentelli of UC Berkeley is renowned for his work in the development of several systems engineering concepts that are being advanced by DARPA in its META project and the Office of the Assistant Secretary of Defense (Research and Engineering) in its Systems 2020 initiative. These concepts include model-based engineering (MBE), platform-based engineering (PBE) and contract-based design (CBD), which enables the development of composable systems. His team has created an automated tool called Metropolis, which allows for the integration of functional models and architecture models to perform abstract, static/descriptive and dynamic modeling and predict the behavior of complex systems. We have begun closer interactions with Prof. Sangiovanni-Vincentelli to apply his techniques to complex systems of interest to Raytheon and our customers.
Interacting with the FCRP
The above examples are the tip of the iceberg. There is much more FCRP research that can have an impact on Raytheon products. Therefore, Raytheon personnel are encouraged to explore collaborations with FCRP faculty. The first step is to visit the FCRP website (http://www.src.org/program/fcrp) and learn more.