Atomically Precise Manufacturing
Questions and Answers



Atomically precise manufacturing — building at the molecular scale with engineering control — is the ultimate Grand Challenge of the National Nanotechnology Initiative. Only a few years ago, this goal sounded like science fiction, but recent scientific results show it is within our grasp, if we rise to the challenge. Developing and commercializing this technology will deliver substantial economic, social, defense, and health benefits to our country—and society in general. Some frequently asked questions and answers concerning this revolutionary technology follow.

What is atomically precise manufacturing?
Atomically precise manufacturing is the ability to manufacture materials and structures at the atomic or molecular size scale. This technology integrates the knowledge and low manufacturing cost of chemistry with the knowledge and flexibility of engineering. The result is a manufacturing technology that achieves the low cost of chemical manufacturing, combined with the engineering mastery that brings us the microchip or suspension bridges, and the flexibility and design freedom offered by computer software. This future manufacturing technology will enable us to make products in a cleaner, cheaper, and faster way than any technology that exists today.

Is the Zyvex approach to atomically precise manufacturing “self-assembly” or some other method?
Self-assembly is a powerful process for creating materials, and a number of research groups are experimenting in the field. Zyvex will utilize some aspects of self-assembly, but the core focus of our technical approach is to create engineered structures by means of parallel, automated assembly of atoms under computer control. This positionally-controlled chemistry allows us to achieve the long-range order of molecular-scale building blocks that is vital to atomically precise manufacturing. On the other hand, self-assembly is sensitive to slight changes in the building blocks, making those systems difficult to engineer. It also suffers from a lack of long-range order. As an example, imagine building a 200-foot brick wall. A pure self-assembly approach would start by randomly laying twenty bricks and building up from each brick independently. One would soon find that the random sections didn’t join with one another, and the resulting brick wall would be weak and ugly. Zyvex’s ordered approach to assembly would start by laying a foundation row of bricks, and building up from there row by row. Long-range order is extremely important to engineering strong, useful structures.

The late Nobel Laureate Professor Rick Smalley said that atomic or molecular assembly won’t work because atom manipulators would be too fat and sticky. Was he right?
Actually we agree with Professor Smalley. However, if you look carefully at what he has said, it does not apply to our approach. Smalley believed that complex, floppy molecules cannot be put together with atomic pick and place techniques. Our target is not the kinds of molecules that living creatures make, but rather rigid, crystalline structures comprised of a small number of elements. Our approach will use parallel arrays of molecular-scale tools operating with high precision to create extremely valuable devices and structures with atomic precision.

Doesn’t quantum mechanics say that since we can’t know where the atoms are, building with atomic precision would be impossible?
Some implications of quantum mechanics are hard to understand, which leads to certain myths about quantum uncertainty. The uncertainty of any particle’s position is related to its momentum (or mass), so while a light electron may have considerable uncertainty in its position and momentum, an atom is much heavier and tends to stay put (which also keeps its electrons nearby). If atoms were as frisky as the “quantum uncertainty” critics claim, solid objects would continually evaporate before our eyes (in fact, life could not exist in such a universe).

3 input sorter

Figure 1.
IBM’s molecular cascade 3-input sorter. CO molecules are arranged on Cu to perform a logic function.

Oxygen on Pt

Figure 2.

Oxygen atoms arranged on Pt surface from “Single Molecule Dissociation by Tunneling Electrons,” B.C. Stipe, M.A. Rezaei, W. Ho, S. Gao, M. Mersson, and B.I. Lundqvist. Phys. Rev. Lett. 78 (1997): 4410-4413.


Figure 3.
Assembled Iron and Cu Carbonyls by Wilson Ho from “Structural Determination by Single-Molecule Vibrational Spectroscopy and Microscopy: Contrast Between Copper and Iron Carbonyls.” H.J. Lee and W. Ho, Phys. Rev. B. 61 (2000): R16347-R16350.

Molecular accelerator

Figure 4.
Molecular accelerator created on Cu surface by Saw Hla, Ohio University.

Is manipulation at the atomic scale really possible?
Yes. The first clear demonstration of the arrangement of atoms was in 1990 when Don Eigler arranged 35 Xenon atoms to spell out IBM.1 Since then, many groups have demonstrated the ability to manipulate atoms into designed structures. Bob Celotta and Joe Stroscio of the National Institute of Standards and Technology (NIST) have gone so far as to make the Autonomous Atom Assembler that can create designed arrangements of atoms in a completely automated fashion.2 Eigler’s team has recently created molecular logic structures (see Figure 1 at left).

The IBM and NIST work just moves atoms around on a surface; however, you are talking about assembling atoms where chemical bonds are broken and made. Is that possible?
As a matter of fact, yes. Wilson Ho3 at UC Irvine, and Saw Hla4 at Ohio University have manipulated atoms and molecules to make and break chemical bonds (see Figures 2 thru 4). Figure 3 shows a clear demonstration of what we call mechanochemistry — where we can move atoms and molecules together to deliberately make and break chemical bonds.

Eigler, Ho, and Hla are manipulating atoms and molecules on surfaces. But you are talking about adding atoms to crystalline structures with atomic precision. Has that even been done?
Yes, it has. Joe Lyding5 at the University of Illinois Urbana-Champaign has shown that he can remove hydrogen atoms adsorbed on atomically flat silicon surfaces. We refer to this as “atomic precision depassivation.” Michelle Simmons6 at the University of New South Wales has used this technique to place a single phosphorous atom at an exact location in a silicon lattice to form a “Qubit” (the fundamental computing element in quantum computation). Lyding7 has recently shown that he can control the growth of single layers of atoms with his depassivation technique to make three-dimensional structures of crystalline silicon.

Won’t thermal vibrations keep you from building with atomic precision? Haven’t you ever heard of “Brownian motion?”
It is well known that atoms are in a state of constant motion due to thermal noise. In liquids, small particles are jostled around by the liquid molecules; an effect called “Brownian motion.” The “thermal noise” critics claim it isn’t possible to build with atomic precision due to this effect. However, careful analysis shows that stiff structures can hold their position with high accuracy even in the presence of thermal noise. This is proven by thousands of researchers worldwide making atomic resolution pictures of atomic structures, and doing the atomically precise manipulations described earlier. If we choose to make our positioning devices with less stiffness, we can cool the environment, which reduces thermal vibration to inconsequential levels. This is not a problem that will stop our progress.

Let’s assume that you can produce atomically precise three-dimensional structures with this technique. Is that just a laboratory curiosity? Is there any near-term return on investment in this technology?
The most valuable structures that could be made with this technique would be tools to enable modestly parallel initially, and then massively parallel systems to produce atomically precise structures more cost effectively. But there are many highly valuable very small structures that could be made with a tool that could only assemble things one atom at a time. One entire class of structures is designed to interact with specific molecules. One example of this is a nanopore that would have the ability to read DNA at up to one million bases per second.8,9 Atomically precise tips for atomic force and scanning tunneling microscopes would have a huge impact on metrology for the semiconductor industry and for science in general. Earlier in this white paper, we mentioned qubit for quantum computing.6 It takes just a handful of qubits to do quantum encryption. There are many other highly valuable products that one could create with early stage atomically precise manufacturing tools.

What about the possibility of creating runaway nanobots that destroy all life?
Science fiction writers love to use a little pseudo-science to tell a good story, but we shouldn’t confuse pseudo-science with reality. We intend to build machines that help us manufacture things with atomic precision. This is grounded in reality, as evidenced in the research we mentioned earlier. Building self-aware machines that reproduce in the wild is science fiction, and likely to remain that way for many decades, even at the macro scale. Nobody knows how to do this sort of thing even with supercomputers, computerized machine shops, and unlimited electric power, so worrying about doing it in specks too small to see, powered by fuel cells we don’t even know how to make, reproducing themselves by some unknown technology, and programmed by genius programmers that haven’t even built a robot as smart as a worm, seems a waste of worry.

General References

1. D. M. Eigler, E.K. Schweizer. Nature 334 (1990): 524.
2. Celotta and Stroscio, “AVS Symposium.” Nov 2003.
3. See twelve papers by Wilson Ho on controlling chemistry at the atomic scale.
4. See eleven papers by Saw Hla on his work on chemistry at the atomic scale.
5. See eight papers by Joe Lyding of hydrogen depassivation.
6. See ten papers by Michelle Simmons on constructions of qubits.
7. Joe Lyding described Patterned ALE at the “AVS Symposium.” March 2003.
8. Dan Branton, Harvard. http://www. mcb.harvard.edu/brantonindex.htm.
9. Viktor Stolc. “Nanopores for Gene Sequencing.” Proposal. NASA Ames Research Center.

Wilson Ho References

• L.J. Lauhon and W. Ho, “The Initiation and Characterization of Single Bimolecular Reactions with a STM.” Faraday Discussion 117 (2000): 249-255.
• L.J. Lauhon and W. Ho. “Inducing and Observing the Abstraction of a Single Hydrogen Atom in Bimolecular Reaction with a Scanning Tunneling Microscope.” J. Phys. Chem. 105 (2000): 3987-3992. 
• G. V. Nazin, X. H. Qiu, and W. Ho. “Visualization and Spectroscopy of a Metal-Molecule-Metal Bridge.” Science 302 (2003): 77-81. Published online September 4, 2003; 10. 1126/Science. 1088971.
• T. M. Wallis, N. Nilius, and W. Ho. “Single Molecule Vibrational and Electronic Analyses of the Formation of Inorganic Complexes: CO Bonding to Au and Ag Atoms on NiAl [110].”
J. Phys. Chem. 119 (2003): 2296-2300.
• N. Nilius, T. M. Wallis, and W. Ho. “Vibrational Spectroscopy and Imaging of Single Molecules: Bonding of CO to Single Palladium Atoms on NiAl[110].” J. Phys. Chem. 117 (2002): 10947-10952.
• W. Ho. “Single Molecule Chemistry.” J. Phys. Chem. 117 (2002): 11033-11061.
• T. M. Wallis, N. Nilius, and W. Ho. “Electronic Density Oscillations in Gold Atomic Chains Assembled Atom by Atom.” Phys. Rev. Lett., 89 (2002): 236802.
• J.R. Hahn and W. Ho. “Oxidation of a Single Carbon Monoxide Molecule Manipulated and Induced with a Scanning Tunneling Microscope.” Phys. Rev. Lett. 87 (2001): 166102.
• L.J. Lauhon and W. Ho. “Single Molecule Chemistry and Vibrational Spectroscopy: Pyridine and Benzene on Cu [001].” J. Phys. Chem. A, 104 (2000): 2463-2467.
• L.J. Lauhon and W. Ho. “Control and Characterization of a Multi-step Unimolecular Reaction.” Phys. Rev. Lett. 84 (2000): 1527-1530. 
• H.J. Lee and W. Ho. “Single Bond Formation and Characterization with a Scanning Tunneling Microscope.” Science, 286 (1999): 1719-1722.
• B.C. Stipe, M.A. Rezaei, W. Ho, S. Gao, M. Persson, a
nd B.I. Lundqvist. “Single Molecule Dissociation by Tunneling Electrons.” Phys. Rev. Lett., 78, 4410.

Saw Hla References

• S.W. Hla, K.F. Braun, K.H. Rieder. Phys. Rev. B, 67 (2003): 201402(R).
• S.W. Hla, K.H. Rieder. Ann. Rev. Phys. Chem. 54 (2003): 307-330.
• S.W. Hla, G. Meyer, K.H. Rieder. Chem. Phys. Lett. 370 (2003): 431-436.
• S.W. Hla. “Nanoscale spectroscopy and its application in semiconductor research.” Edited by Y. Watanabe, S. Heun, G. Salviati, N. Yamamoto. Lecture Notes in Physics (Springer Verlag Heidelberg), (2002): 222-230.
S.W. Hla, K.H. Rieder. “Superlattices & Microstructures.” 31 (2002): 63-72.
• A. Kühnle, G. Meyer, S.W. Hla, K.H. Rieder. Surf. Sci. 499 (2002): 15-23.
• G. Meyer, F. Moresco, S.-W. Hla, J. Repp, K.-F. Braun, S. Foelsch, K.H. Rieder. Jap. J. Appl. Phys. 40 (2001): 4409-4412.
• S.W. Hla, G. Meyer, K.H. Rieder. “Inducing Single Molecule Chemical Reactions with STM: A New Dimension for Nano-Science and Technology.” Chem Phys Chem. 2 (2001): 361-366.
• S.W. Hla, L. Bartels, G. Meyer, K.H. Rieder. “Inducing all steps of a chemical reaction with the scanning tunneling microscope tip: Towards single molecule engineering.” Phys. Rev. Lett. 85 (2000): 2777-2780.
• S.W. Hla, A. Kuhnle, G. Meyer, K.H. Rieder. “Controlled lateral manipulation of single diiodo-benzene molecules on the Cu surface with the tip of a scanning tunneling microscope.” Surf. Sci. 454-456 (2000): 1079.G. Meyer, J. Repp, S. Zöphel, K.F. Braun, S.W. Hla, S. Fölsch, L. Bartels, F. Moresco, K.H. Rieder. “Controlled manipulation of atoms and small molecules with a low temperature scanning tunneling microscope.” Single Molecule 1 (2000): 79-86.

Joe Lyding References

• M. C. Hersam, N. P. Guisinger, and J.W. Lyding. “Silicon-based molecular nanotechnology.” Nanotechnology 11 (2000): 70.
• G.C. Abeln, M.C. Hersam, D.S. Thompson, S.T. Hwang, H. Choi, J.S. Moore, and J.W. Lyding. “Approaches to Nanofabrication on Si Surfaces: Selective Area CVD of Metals and Selective Chemisorption of Organic Molecules.” J. Vac. Sci. Technol. B 16 (1998): 3874.
• M. C. Hersam, J. Lee, N. P. Guisinger, and J.W. Lyding. “Implications of atomic-level manipulation on the Si [100] surface: From enhanced CMOS reliability to molecular nanoelectronics.” Superlattices and Microstructures 27 (2000): 583.
• M.C. Hersam, G.C. Abeln, and J.W. Lyding, “An Approach for Efficiently Locating and Electrically Contacting Nanostructures Fabricated via UHV-STM Lithography on Si [100].” Micro-electronic Engineering 47 (1999): 235.
• I.C. Kizilyalli, K. Hess, and J.W. Lyding, “Channel Hot Electron Degradation-delay in MOS Transistors Due to Deuterium Anneal.” The VLSI Handbook Chapter 13. CRC Press LLC. (1999).
• J. Lee, Y. Epstein, A.C.erti, J. Huber., K. Hess, and J.W. Lyding. “The Effect of Deuterium Passivation at Different Steps of CMOS Processing on Lifetime Improvements of CMOS Transistors,” IEEE Transactions on Electron Devices, 46 (1999): 1812.
• J.W. Lyding, K. Hess, G.C. Abeln, G.C. Thompson, J.S. Moore, M.C. Hersam, E.T. Foley, J. Lee, Z. Chen, S.T. Hwang, H. Choi, P.H. Avouris, and I.C. Kizilyalli, “UHV-STM Nano-fabrication and Hydrogen/Deuterium Desorption from Silicon Surfaces: Implications for CMOS Technology,” Applied Surface Science, 130-132 (1998): 221.
• Foley, E. T., Kam, A. F., Lyding, J. W., and Avouris, P. H. “Cryogenic UHV-STM Study of Hydrogen and Deuterium Desorption from Si [100],” Physical Review Letters, 80/6 (1998): 1336-1339.

Michelle Simmons References

• J.L. O’Brien, S.R. Schofield, M.Y. Simmons, R.G. Clark, A.S. Dzurak, N.J. Curson, B.E. Kane, N.S. McAlpine, M.E Hawley and G.W. Brown. “Towards the fabrication of phosphorus qubits for a silicon quantum computer”, Phys. Rev. B, 64 (2001): 161401.
• L. Oberbeck, N.J. Curson, M.Y. Simmons, R. Brenner, A.R. Hamilton, S.R. Schofield and R.G. Clark. “Encapsulation of phosphorus dopants in silicon for the fabrication of a quantum computer.” Applied Physics Letters 81 (2002): 3197.
• A.S. Dzurak, M.Y. Simmons, A.R. Hamilton, R.G. Clark, R. Brenner, T.M. Buehler, N.J. Curson, E. Gauja, R.P. Mckinnon, L.D. Macks, M. Nitic, J.L. O’Brien, L. Oberbeck, D.J. Reilly, S.R. Schofield, F.E. Stanley, D.N. Jamieson, S. Prawer, C. Yang and G.J. Milburn/ “Construction of a silicon-based solid state quantum computer.” Quantum Information and computation 1 (2001): 82.
• J.L. O’Brien, S.R. Schofield, M.Y. Simmons, R.G. Clark, A.S. Dzurak, N.J. Curson, B.E. Kane, N.S. McAlpine, M.E. Hawley and G.W. Brown. “Nanoscale phosphorus atom arrays created using STM for the fabrication of a silicon based quantum computer.” BioMEMS and Smart Nanostructures 4590 (2001): 299.
• J.L. O’Brien, S.R. Schofield, M.Y. Simmons, R.G. Clark, A.S. Dzurak, N.J. Curson, B.E. Kane, N.S. McAlpine, M.E. Hawley, and G.W. Brown. “Scanning tunneling microscope fabrication of arrays of phosphorus atom qubits for a silicon quantum computer.” Smart Materials and Structures 11 (2002): 741.
• M.E. Hawley, G.W. Brown, M.Y. Simmons and R.G. Clark. “Fabricating a qubit array with a scanning tunneling microscope.” Los Alamos Science 27 (2002): 302.
• M. Y. Simmons, S. R. Schofield, J. L. O’Brien, N. J. Curson, L. Oberbeck, T. Hallam and R. G. Clark. “The atomic-scale fabrication of a solid-state silicon based quantum computer.” Surface Science. July 2002.
• N.J. Curson, S.R. Schofield, M.Y. Simmons, L. Oberbeck and R.G. Clark. “Critical issues in the formation of atomic arrays of phosphorus in silicon for the fabrication of a solid-state quantum computer.”Surface Science. July 2002.
• L. Oberbeck, N.J. Curson, M.Y. Simmons, S.R. Schofield and R.G. Clark, “Challenges in surfaces for quantum computing.” Surface Review and Letters. August 2002.
• L. Oberbeck, T. Hallam, N.J. Curson, M.Y. Simmons and R.G. Clark, “Epitaxial silicon growth in the presence of hydrogen.” Applied Surf. Sci. (2002).

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