Findings and Recommendations
The committee reached a number of critically important broadly applicable findings and recommendations, which are presented in the first section of this chapter. Findings and recommendations related to technological developments in micro- and nanotechnologies are followed by policy recommendations. Findings and recommendations are presented in a logical flow. The numbering does not represent a rank ordering but simply serves as an identifier. In addition, a number of the committee’s more specific findings and recommendations are listed in the second section of the chapter.
CRITICAL FINDINGS AND RECOMMENDATIONS
Four overarching themes emerged from the committee’s study of the implications of emerging micro- and nanotechnologies: increased information capabilities, miniaturization, new materials, and increased functionality and autonomy (T8). The following findings and recommendations attempt to capture the essence of these themes with some specificity. The increased information capabilities flow from near-term continuation of the scaling of silicon electronics (T1) and from new and alternative concepts arising from nanotechnology research (T2). Biological science, both as inspiration (biomimetics) and as a functional contributor, offers new opportunities (T3) that build on and complement traditional sensing, computing, and communications approaches. Increased information capabilities and miniaturization together will make possible large distributed
arrays of sensors (sensor swarms) on combinations of fixed and movable platforms. These array systems will exhibit new or emergent properties significantly different from those of individual components and will allow increasingly autonomous operation of Air Force systems (T4). Harnessing the capabilities of microelectromechanical systems (MEMS) to propulsion and aerodynamics will allow miniaturization of air and space platforms (T5). Maximizing the utility of these growing capabilities in information technology, biomimetics, individual sensors and sensor swarms, and MEMS actuators for the Air Force will demand specific attention to system design, architecture, and software for system implementation (T6). Because of the wide range of new capabilities being enabled, the trend to merging heterogeneous materials systems and to expanding the range of materials in micro- and nanoscale devices and systems is inexorable (T7).
Finding T1. Further miniaturization of digital electronics with increased density (~128×) is projected by the integrated circuit industry over the next 15 years based on continued scaling of current technology. The most recent ITRS forecasts the accelerated introduction of smaller dimensions and greater computational power than were forecast by the ITRS 2 years ago.
Recommendation T1. The Air Force should position itself to take advantage of the advances predicted by the Information Technology Roadmap for Semiconductors. Dramatic advances are predicted for device technology. Software, application-specific integrated circuits (ASICs), embedded computers integrating software and hardware for specialized applications, and radiation-hardening and packaging for hostile environments must be designed by, and for, the military, to take advantage of these advances.
Finding T2. In anticipation of an ultimate end to the historical scaling of today’s integrated circuit technology, many new and alternative concepts involving nanometer-dimensioned structures are being examined. As yet, none of these concepts had demonstrated the necessary functionality and integrability to be a clear choice for “beyond silicon.” Many different material and device technologies will need to be explored well into the future. Two facts seem clear. First, it is not possible to make reliable, long-term predictions of breakthrough capabilities emerging from the rich frontier of discovery, fabrication, and material properties at nanometer dimensions. The numerous avenues of research investigation are likely to uncover unexpected processes and/or material properties that will have an impact at the fundamental level of information processing. Second, it seems likely that the initial applications of any of these technologies will build on and enhance the very strong base of existing integrated circuit technology, which will provide the necessary backbone of functionality and integrability until an entirely new computation paradigm emerges.
Recommendation T2. Exploration of the scientific frontiers involving new procedures for fabrication at nanodimensions and new nanoscale materials, properties, and phenomena should be supported. The Air Force should track, assimilate, and exploit the basic ideas emerging from the research community and continue to support both intra- and extramural activities. The focus should be on understanding the fundamental processes for fabrication, and on the unique properties of materials and devices structures at nanometer dimensions. Extremely dense arrays of devices capable of manipulating bits rapidly and reliably should be a dominant aspect of these investigations. Individual devices with nanometer or molecular dimensions are demonstrating logical functions on a small scale with a limited number of examples. Molecular electronics appears promising at present. There is potential for new device innovations and for progress in computing architectures and strategies. Quantum computing and quantum cryptography are examples of the applications that may be enabled by further progress in micro- and nanotechnology. The technology may develop rapidly once the scientific principles and technological advantages are discovered and understood.
Finding T3. Biological science offers new opportunities in nanotechnology systems, especially for sensors, materials, communications, computing, intelligent systems, human performance, and self-reliance. Millions of years of evolution have produced highly specialized sensing and communication capabilities in nature. Understanding of how these sensors work is growing but is still very limited. As the fundamental mechanisms are discovered and studied, applications rapidly follow. Advances in micro- and nanotechnology have enabled discovery in biological systems, which in turn has provided new means of sensing and communicating. Clearly, advances in technology and in the biological sciences go hand in hand in developing new capabilities.
Recommendation T3. The Air Force should closely monitor the biological sciences for new discoveries and selectively invest in those that show a potential for making revolutionary advances or realizing new capabilities in Air Force-specific areas.
Finding T4. Large, distributed fixed arrays and moving swarms of multispectral, multifunctional sensors will be made possible by emerging micro-and nanotechnology, and these will lead to significant fundamental changes in sensing architectures. Concepts such as smart dust and distributed communication networks actively exploit the technological capabilities of emerging micro- and nanotechnologies. The fusion of data from large numbers of sensors as well as large numbers of sensor types will drive research in new networking concepts.
Recommendation T4. The Air Force should develop balanced research strategies for not only the hardware but also the requisite software and software architectures for fixed arrays and moving swarms of multispectral, multifunctional sensors.
Finding T5. Emerging microtechnology offers new opportunities in propulsion and aerodynamic control, in particular in (1) distributed sensors and actuators on both macro-aerodynamic surfaces and macro-aeropropulsion units and (2) new, scalable, miniaturized and distributed aero- and space-propulsion systems. Emerging microtechnology has achieved preliminary success in sensing and controlling the boundary layer on full-size, subsonic airfoils. New devices for controlling gas and liquid flow, fabricated using microtechnology, promise to increase the power and reliability of air-breathing, full-size propulsion units. Several new aeropropulsion and space propulsion systems, such as micro turbine engines and micro rocket engines, have been fabricated and are in the early test phase.
Recommendation T5. The Air Force should move decisively to develop new research and development programs to bring microtechnology to both macro- and microscale propulsion and aerodynamic control systems.
Finding T6. The Air Force strategic nanotechnology R&D plan, as presented to the committee, is focused on hardware concepts without appropriate consideration of total systems solutions. It is well known that over the past 15 years the commercial sector has made increasing investments in architecture and software concepts to design advanced systems. The tendency has been toward codesign of the hardware and software aspects of a system. One implication of nanotechnology is that this approach will be even more essential as device capabilities continue to expand. New algorithms, architectures, and software design methods will need to be developed and employed in concert with new nanotechnology-based hardware. Investment in this strategy will enable autonomous, intelligent, self-configuring Air Force systems. The Air Force strategic plan contains many future scenarios where such systems would be the ideal, if not the only, solution.
Recommendation T6. The Air Force should take seriously the importance of co-system design as a critical implication of continued miniaturization and should invest in the algorithm, architecture, and software R&D that will enable the codesign of hardware and software systems. This should be undertaken along with a projection of the advances that will be made in hardware.
Finding T7. Integration of micro- and nanoscale processes and of different material systems will be broadly important for materials, devices, and pack-
aging. Self-assembly and directed assembly of dissimilar elements will be necessary to maximize the functionality of many micro- and nanoscale structures, devices, and systems. Achievement of high yields and long-term reliability, comparable to those of the current integrated circuit industry, will be a major challenge.
Recommendation T7. The Air Force should monitor progress in self- and directed-assembly research and selectively invest its R&D resources. It will be critical for the Air Force to participate in developing manufacturing processes that result in reliable systems in technology areas where the military is the dominant customer—for example, in sensors and propulsion systems. Developments in many of these areas will be driven by the commercial sector. The Air Force must stay aware of advances and apply them to its unique needs. As an example, in sensor applications a wide range of otherwise incompatible materials and fabrication processes is likely to be necessary.
Finding T8. Four overarching themes emerge from the advance of micro-and nanotechnologies—increased information capabilities, miniaturization, new engineered materials, and increased functionality/autonomy. These themes could have a significant military impact by enabling new systems approaches to Air Force missions.
Recommendation T8. The Air Force should continue to examine new systems opportunities that may emerge from the successful development of micro- and nanotechnologies and use these studies to help focus its applied research and development investments in these technologies.
The Air Force critically depends on advanced technology to accomplish its missions. In order to maintain the nation’s competitive technology advantage over the long term, the Air Force must maintain a stable, robust, and effective RDT&E program. The Air Force is currently underinvesting in this critical area and has not maintained the stability necessary for sustained progress, thereby shortchanging its future and that of the nation (P1). An important new development is that the commercial sector now overshadows the military market. This means that product development is driven by commercial, not military, requirements. The DoD cannot, however, rely solely on commercial R&D and products to satisfy its needs (P2). Micro- and nanotechnologies are going to play a significant role in future Air Force systems, as detailed in the technical sections of this report (the basis for findings and recommendations T1-T8 above). The Air Force
Research Laboratory has initiated a planning process to enhance its effectiveness in this all-important area (P3), but more needs to be done to strengthen the Air Force’s internal programs and to ensure that they assimilate and leverage the results of the very extensive programs under way throughout the worldwide scientific community (P4).
Finding P1. Both overall DoD and—even more—Air Force policies have de-emphasized R&D spending to the detriment of DoD and Air Force long-term needs. The Air Force relies heavily on the technological sophistication of its platforms, systems, and weapons. Its ability to meet its long-term objectives is critically dependent on a strong and continuing commitment to R&D.
Recommendation P1. The Air Force must significantly increase its R&D funding levels if it is to have a meaningful role in the development of micro-and nanotechnology and if it is to be effective in harnessing these technologies for future Air Force systems. DoD and the Air Force have historically funded a majority share of the nation’s research in information technologies. Their funding retrenchment represents a national de-emphasis on the future of this critically important war-fighting capability.
Finding P2. The military market for many micro- and nanotechnologies (e.g., advanced computing, communications, and sensing) is small in comparison with commercial markets. Yet, the Air Force and DoD have mission-specific requirements not satisfied by the commercial market. Military-specific applications will not be supported by industry without government and Air Force investment, particularly in basic research.
Recommendation P2. The Air Force should concentrate its efforts in micro-and nanotechnology on basic research at the front end and on Air Force-specific applications at the back end. Rather than competing with the commercial sector, Air Force should stay strongly connected to commercial advances and adapt them to Air-Force-specific requirements.
Finding P3. The Air Force has recognized the importance of micro- and nanotechnologies for its future capabilities and has begun a planning process to maximize the benefits of the in-house and extramural research programs. Strong leadership will be necessary to ensure maximum benefit from the Air Force Research Laboratory research programs. The Air Force has coupled its programs with other research programs within DoD, especially those of DARPA and DDR&E.
Recommendation P3. It will be critical to continue the planning for micro-and nanotechnologies at the highest levels of the Air Force Research Labo-
ratory (AFRL). AFRL should also strengthen its external review processes to assist the leadership and to ensure that its work is well coordinated with national efforts. The Air Force should coordinate its initiatives with other federal agencies and work to build collaborative programs where appropriate.
Finding P4. The committee perceived a lack of consistency in the quality of current in-house Air Force programs and in the benchmarking of those programs against the large number of programs under way throughout the world.
Recommendation P4. Considering that micro- and nanotechnology is a new and rapidly emerging interdisciplinary field, the Air Force should critically evaluate its efforts in micro- and nanotechnology to select areas of strong potential payoff for Air Force missions and to sustain the highest-quality program. This will require the following:
Long-term professional participation of Air Force personnel as active partners with the external micro- and nanotechnology community.
Strong leadership and technical evaluation at the highest levels of AFRL technical leadership, as has already begun.
Both fundamental research and focused, interdisciplinary development efforts. Fundamental research efforts are required to sustain a cadre of scientists with a deep understanding of both micro- and nanotechnology developments and of Air Force requirements. Interdisciplinary development efforts put an essential Air-Force-specific overlay on this fundamental research and force multidisciplinary teams to confront real system- and subsystem-level problems, which is essential for bringing any technology from the laboratory bench to practical application.
SPECIFIC FINDINGS AND RECOMMENDATIONS
Specific findings and recommendations are listed in this section.
Finding 3-1. Space electronics is vital to the Air Force mission. The unique characteristics of the exoatmospheric environment place special demands on electronics that are outside the mainstream developments of the integrated circuit industry.
Recommendation 3-1. The Air Force must maintain a research and development effort in radiation-hardened electronics and must evaluate the continuing developments of micro- and nanotechnology for their applicability to
space. Some commercial developments, such as the move to silicon-on-insulator (SOI) materials, have clear radiation hardness benefits; others, such as molecular electronics, have yet to be evaluated in this context but are likely to exacerbate the problems.
Finding 3-2. Communication is a critical aspect of information superiority. The continuing trend to miniaturization is evident in this area as well as in computation. Traditionally, communication has been dependent on a wider materials base than computation as a result of the need for optical interactions and for high-speed analog functions at microwave and RF frequencies. The Air Force has unique communications requirements, different from those of the commercial sector, demanding sustained effort and the overlay of scientific advances with Air Force requirements.
Recommendation 3-2. The Air Force should maintain a strong research program in both the optical and microwave/RF regimes. MEMS technology is having a strong impact. Nanotechnology is already leading to advances in these areas as well as in computation.
Finding 3-3. In sensors, especially for remote sensing applications of importance to the Air Force, there are a large number of high-performance requirements and military-specific functions that are clearly beyond the scope of commercial interests.
Recommendation 3-3. The Air Force should support in a sustained manner the research, development, and manufacturing infrastructure for military sensor systems.
Finding 3-4. The resurgence of the commercial MEMS sensor industry represents an opportunity for the U.S. Air Force to harvest improvements in military-specific MEMS devices. The maturing of the overall MEMS industry and increased MEMS activity in the telecommunications market have dramatically increased the performance of design tools and the availability of complex space-qualified MEMS devices.
Recommendation 3-4. The Air Force should actively pursue improvements and/or adaptations of commercial efforts for military needs and be prepared for a larger investment at the 6.2 through 6.4 levels. This recommendation is not meant to imply total reliance on commercial sources. Commercial interests may drive the market in a different direction than is needed by the military, and commercial interests may interfere with military interests in the MEMS-based community.
Finding 3-5. The application of nanoscience to structural materials is a promising area with important implications for Air Force systems. Such materials could be used for lightweight structures, improved coatings, multifunctional structures, and micromachined structures. Military-specific structural materials applications need special attention by the Air Force. Many of the emerging nanoscience developments will march ahead without regard to potential Air Force needs or imperatives, and some will find their way into commercial products. However, some military structural materials needs will never be addressed by commercial industry. These include stealthy structures, thermal management structures for spacecraft, lighter-weight military aircraft, and structures for reduced logistics and maintenance costs. However, if the Air Force is to exploit and implement the most compelling advances, even those from the commercial world, then aerospace system designers and manufacturers and their suppliers as well as the Air Force users must constantly be aware of those advances. There need to be mechanisms to link technical developments to military system applications throughout the entire supply chain.
Recommendation 3-5. The AFRL should continue its strong efforts in structural materials to capitalize on research and development advances. The Air Force should invest in establishing capability on the part of contractors to supply selected military-specific products at the same time as it invests at AFRL to encourage collaboration with cutting-edge researchers and the comprehensive tracking, where possible, of research and development and steering it toward Air Force needs.
Finding 3-6. Nanoscience as applied to the structural materials used for MEMS components is key to the successful deployment of MEMS technology. Unresolved issues such as stiction prevention, sidewall morphology, and durability and stability of micromechanical structures are obstacles to the deployment of reliable MEMS sensors and actuators in military systems.
Recommendation 3-6. The Air Force should focus development resources on materials issues that currently limit MEMS deployment for the military. These include structural stability, surface durability, manufacturable fabrication processes, and packaging.
Finding 4-1. Lithography and pattern transfer and self-assembly are key enablers for evolving micro- and nanotechnologies.
Recommendation 4-1. The AFRL R&D program will require access to micro- and nanolithography and pattern transfer tools. This should be accomplished using available national facilities or otherwise providing the
function internally. Research into new nanolithography and patterning technologies, complementary to the industry push for high-throughput tools, would be a worthwhile investment. The Air Force should not compete with industry efforts, particularly in silicon technology, but should concentrate on developing processes for structures and materials that are outside traditional silicon processing—for example, deep etching for MEMS and integration of new materials with silicon.
Finding 4-2. So much is already known about progress in silicon, with its already highly developed and constantly improving manufacturing processes, that it is unlikely a sui generis technology will spring up sufficiently developed and robust that it will immediately supplant not only the transistor but also all the rest of the integrated circuit. Integrated circuit technology has become extremely sophisticated, and the industry is devoting extensive resources to extending this sophistication in its drive to validate Moore’s law for future IC generations. In contrast, nanotechnology is at a much earlier development stage, concentrating on the behavior of individual devices and circuit components (switches, wires, etc.). It is most likely that these new technologies will first find use as complements to silicon, not as immediate replacements for integrated circuits. Over the longer term, it is not possible to predict the relative roles of integrated circuits and new and evolving nanotechnologies.
Recommendation 4-2. The Air Force should emphasize those areas of micro- and nanotechnology for information processing that are potentially integrable with silicon technology and that address Air Force-specific, non-commercial military applications.
Finding 4-3. The path from laboratory demonstration to the manufacture of reliable devices and systems is long and arduous, requiring extensive resources and prodigious technology development. This will undoubtedly be as true of today’s emerging technologies as it has been throughout the history of technology. It is worthwhile to consider this lesson when listening to the siren songs appearing daily, particularly in the popular and business press, on the future benefits of nanotechnology. There is undoubtedly an exciting future, and just as undoubtedly, we will find many surprises, both positive and negative, along the way.
Recommendation 4-3. Air Force research efforts should be directed not only to the science of micro- and nanotechnology, but also to the development of devices and systems and wide access to the manufacturing technology required to produce them.