When Galileo aimed his telescope at the heavens to observe and study the stars and planets, he changed the world forever. Great discoveries in science are often made with the help of great instruments. And new instruments lead to new discoveries. In our own time, we are witnessing a renaissance in telescope development, giving us a seemingly endless stream of spectacular images of all that makes up our universe. Huge rockets transported man to the moon and back. The inside of the human body is open to scrutiny without even the touch of a hand with the advent of computer-aided tomography (CAT) and magnetic resonance imaging (MRI). Automated sequencing machines are taking apart the human genome, laying bare the most intimate language of life, to be deciphered like an ancient language. Synchrotron X-ray data are used to determine the three-dimensional structure of a protein in just a few months, and new, powerful computers may soon calculate that structure from scratch. The scanning tunneling microscope allows us not only to see and contact the world of atoms, but to move atoms around and place them where we want. The electron microscope has given us a view of the microstructure of the material world, its symmetries and its defects. The largest and most costly scientific instruments uncover the structure of the sub-atomic world, with large international teams of scientists and engineers herding bursts of particles through miles and miles of tunnel.

But engineering closely follows this curiosity and ingenuity. Goddard's rockets not only delivered man to the moon, they also sent communications satellites into orbit. The sub-atomic world has given us quarks, it may bring us the Grand Unified Theory; but it has also handed us the most fearful weapons ever developed. CAT scans and MRIs are used to find the causes and effects of disease and trauma, and bring cures to human suffering. We are splicing genes even if we are less than fluent in the genetic language, creating new crops and new medicines. The computer, born in the minds of mathematicians, has changed forever how we do business, is revolutionizing our ways of communicating, and also plays a mean game of chess.

As new tools enable us to better understand materials properties and phenomena, they also help us invent, control, and engineer future technology generations. The papers in this issue describe emerging analytical techniques being investigated at IBM Research and their applications in the fields of microelectronics, storage, and displays.

IBM and MIT developed the X-ray scattering beamline at the National Synchrotron Light Source on Long Island to study the adsorption of xenon on graphite—an important problem in basic science—and to understand new phases in Van der Waals-bonded thin films. In her paper, Jean Jordan-Sweet describes use of the beamline to study phase transformations in silicides, strains in thin and narrow metal wires, and a host of other microelectronics-related materials phenomena, and to help develop and improve the interconnections between transistors in integrated circuits.

The scanning transmission electron microscopy technique described by Philip Batson is based on the use of electron energy loss spectroscopy to study the electronic structure of materials on a 0.2-nm length scale. It can be used to detect contamination layers that—although only an atomic layer thick—can degrade the functioning of a transistor, or it can be used to identify the electron states near dislocations that scatter electrons from their designated paths.

The ultrahigh-vacuum transmission electron microscope described by Frances Ross makes it possible to observe the self-assembly of quantum dots, little specks of solid that in many ways behave like single atoms, even though each speck contains thousands of them. Such quantum dots hold promise for new materials and devices, and it is critical that their properties are carefully controlled. In her paper she also describes the use of the microscope to observe phase transformations in silicides.

Low-energy electron microscopy, as discussed in my paper, has been used to study a rather esoteric order­disorder phase transition on Si(113), a two-dimensional equivalent of what happens when a magnet passes through the Curie point and ceases to be a permanent magnet. It has also been used to understand the growth of Ge and SiGe alloys on Si, to observe breakdown phenomena in thin gate oxide films, and to help develop a new lithography method.

In his paper, Rudolf Ludeke describes the study of thin oxide films using ballistic electron emission microscopy, a technique closely related to scanning tunneling microscopy. Oxide degradation, charge accumulation in the oxide film, electron resonance effects, and other oxide properties can be probed on nanometer length scales with exquisite sensitivity.

Photoelectron emission microscopy, in combination with the special polarization properties of synchrotron-generated ultraviolet photons, allows the imaging of the magnetic structure of bulk materials and thin films. In their paper, Joachim Stöhr and Simone Anders describe the use of linear and circular dichroism effects to obtain images of the magnetic structure in storage media, antiferromagnets, and a host of other magnetic materials.

Scanning electron microscopy with polarization analysis makes use of the quantum-mechanical spin of the electrons to probe the magnetic microstructure of materials, as described in the paper by Rolf Allenspach. The hysteresis curve of a magnetic material can be followed on a microscopic scale by imaging the switching of small magnetic areas from one magnetization state to the other, until complete magnetization reversal has been achieved. The paper also describes how a powerful electron beam pulse can induce magnetic field switching on picosecond time scales.

Matthew Copel describes the use of medium-energy ion scattering, developed more than twenty years ago to elucidate the atomic structure of atomically clean surfaces. This technique has now become invaluable in determining the structure and composition of thin films. For instance, it has shed much light on the growth, composition, and properties of thin gate oxide films.

Finally, James Tsang, Jeffrey Kash, and David Vallett describe an optical technique to monitor integrated circuit behavior. The technique is based on the light emission from a field-effect transistor (in picosecond bursts) whenever it switches. The picosecond imaging for circuit analysis technique is the last technique discussed in this issue. By imaging the light emission with picosecond resolution, electrical signals can be followed as they travel through a computer chip. Moving pictures can be made of a clock circuit in operation. Parts of the chip that are active can be easily distinguished from parts that are dormant, much as the lights of a big city surrounded by dark countryside catch the eye of a passenger in a plane flying over at 30000 feet.

In summary, all of these techniques and methods started off as a twinkling in an eye, a researcher who had an idea to put a hook in a little piece of reality that had previously escaped from scrutiny. The researcher uncovers a new piece of science. But soon the new instruments take on a life of their own, leading into new territory and showing the way to new materials, new designs, new concepts. Their continued development will ensure us a vibrant and ever-changing future in science and technology.

Rudolf Tromp Manager, Analytical Sciences Department IBM Thomas J. Watson Research Center Guest Editor