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Amorphous Co:Si (1:2 ratio) films are electron gun-evaporated on clean Si(111), such as in a molecular beam epitaxy system. These layers are then crystallized selectively with a focused electron beam to form very small crystalline Co/Si2 regions in an amorphous matrix. Finally, the amorphous regions are etched away selectively using plasma or chemical techniques.

E-beam generated ultrastructures on oxide film substrates have been investigated for high density memory and lithographic applications. In order to create the nanometer scale patterns (holes, lines, channels), a dedicated STEM have been used and also used for exposure studies, imaging, microdiffraction analysis and monitoring the transmitted beam studies. Amorphous films of A1203, Y203, SC203, 3Al2O3-2SiO2, and MgO.Al2O3 are deposited on to substrate at cryogenic temperature. Amorphous film structure is necessary to achieve rapid removal of material during e-beam exposure. Hole resolution in the sputtered oxide films of 5 nm holes on 8.1 nm centers was achieved with exposure times in the millisecond range, 2 - 3 orders of magnitude lower than produced by other technique. Deposition parameters and film thickness have been studied. The gas ambient on thin films electron dose are strongly related to the drilling speed. A possible mechanism for the exposure process is also developed. Lithography, Nanostructure, Oxide, E-beam, Memory.

E-beam generated ultrastructures on oxide film substrates have been investigated for high density memory and lithographic applications. In order to create the nanometer scale patterns (holes, lines, channels), a dedicated STEM have been used and also used for exposure studies, imaging, microdiffraction analysis and monitoring the transmitted beam studies. Amorphous films of A1203, Y203, SC203, 3Al2O3-2SiO2, and MgO.Al2O3 are deposited on to substrate at cryogenic temperature. Amorphous film structure is necessary to achieve rapid removal of material during e-beam exposure. Hole resolution in the sputtered oxide films of 5 nm holes on 8.1 nm centers was achieved with exposure times in the millisecond range, 2 - 3 orders of magnitude lower than produced by other technique. Deposition parameters and film thickness have been studied. The gas ambient on thin films electron dose are strongly related to the drilling speed. A possible mechanism for the exposure process is also developed. Lithography, Nanostructure, Oxide, E-beam, Memory.

We report an ab-initio investigation of several possible Si and Ge pristine nanowires with diameters between 0.5 and 1.2 nm. We considered nanowires based on the diamond structure, high-density bulk structures, and fullerene-like structures. We find that the diamond structure nanowires are unstable for diameters smaller than 1 nm, and undergo considerable structural transformations towards amorphous-like wires. Such instability is consistent with a continuum model that predicts, for both Si and Ge, a stability crossover between diamond and high-density-structure nanowires for diameters smaller than 1 nm. For diameters between 0.8 nm and 1 nm, filled-fullerene wires are the most stable ones. For even smaller diameters (d~0.5 nm), we find that a simple hexagonal structure is particularly stable for both Si and Ge.

The Proceedings of the 26th Annual Conference on the Physics and Chemistry of Semiconductor Interfaces (PCSI-26) are contained in this volume. The Conference was held at the Catamaran Resort Hotel in Pacific Beach, San Diego, California from Sunday evening, 17 January 1999 to noon on Thursday 21 January 1999 A total of 18 invited and 69 contributed papers were presented, with 113 attendees. This year's Conference saw a large number of papers relating to nitride semiconductor interfaces and piezoelectric effects (41) reflecting the increasing interest in that field worldwide. Besides the traditional emphasis on growth and characterization of other compound semiconductor interfaces (35) a significant number of papers addressed the chemistry and physics of SiO2/Si interfaces (23). There were also a small but significant number of papers dealing with magnetic materials, and spin transport (6), an area that the PCSI Committee believes will increase in the future. Carol Ashby presented some interesting new results on the role of As in oxidation of AlGaAs layers. Steve Streiffer gave an overview of recent work on Perovskite structure ferroelectric films for possible gate dielectrics in transistors. Other exciting advances reported at the Conference include: silicon substrate-based optoelectronic structures predicted by John Joannopoulos from MIT, MBE studies of GaN growth, impurity and surfactant effects in GaN total energy calculations, and real-time x-ray scattering studies of MOCVD growth of GaN films. The Tuesday Rump session's theme this year was piezoelectric effects at semiconductor interfaces and included stimulating talks by D. L. Smith and a number of others.

The Twenty-Third Annual Conference on the Physics and Chemistry of Semiconductor Interfaces was held in Lajolla, California and the enclosed report contains papers presented.

Highlights of the full reporting period include the construction of a custom-built low-temperature high magnetic field STM with ultra high vacuum sample preparation, the first of its kind. Key experimental results were obtained in STM studies of Kondo lattice and in behavior of Kondo effect in magnetic fields. IBM achieved its milestone of demonstrating single-atom spin-flip spectroscopy, published in Science (2004). IBM finalized its work on the spectroscopic properties of physisorbed molecular hydrogen in nanoscopic junctions, finding unusual excitations. Finally, IBM found when Mn atoms were placed near the edge of thin oxide islands, an enhanced zero bias conductance emerged, a notably clear manifestation of the Kondo effect.

An investigation was performed to study the effect a heterogeneous surface consisting of nanometer scale square posts patterned into micron scale checkerboard shapes had on surface hydrophobicity and water adhesion. In addition to altering surface geometries, different surface coatings were investigated. Conformal thin films of PDMS, CYTOP, and Teflon AF were made using a surface grafting technique and applied to each nano-scale and micro-scale design fabricated for this study. Both the static contact angle and the tilt angle required for a water drop to roll-off the surface were measured to determine the wetting state for a particular surface geometry. For nano-scale posts with spacing-to-width ratios below a certain threshold value, patterned into micro-scale checkerboard shapes with a spacing-to-width ratio - I, the hydrophobicity of a surface was increased compared to a surface made of either all nano-scale features or all micro-scale features. Conversely, as the spacing-to-width ratio of the nano-scale square posts increased above the threshold value, for the micro-scale checkerboard shapes having a spacing-to-width ratio 5: I the surface hydrophobicity was reduced and water adhesion increased compared to a surface made of either all nano-scale features or all micro-scale features. The nano-scale spacing-to-width ratio threshold value that caused this behavior to occur was dependent on both post width and surface coating. Finally it was observed, that for the micro-scale checkerboard shapes having a spacing-to-width 1, the micro-scale features dominated the wetting state regardless of the nano-scale post geometry.

This report covers (1) length scales, (2) thermal effects in metallic nanowires, and (3) heating in metallic point contacts. It concludes with the following points: (1) high current densities in nanowires, (2) wires/contacts approximately several nm in size stable at high current densities, (3) for STM point contacts light emission is consistent with high electron temperature, (4) divergence of electron and lattice temperature.

E-beam generated ultrastructures in oxide and halide film substrates have been investigated for high density memory and lithographic applications. In order to create the nanometer scale patterns (holes, lines, channels), a dedicated STEM was used and also used for exposure studies, imaging, microdiffraction analysis and for monitoring the transmitted beam. High ionic character, high heat of formation and high melting point were identified as desirable material characteristics by the oxide film studies. Therefore, halide materials were studied in order to evaluate the formation time for its film structures using the e-beam method. Amorphous AlF3 film was deposited on to substrate at cryogenic temperature. Hole resolution in the sputtered halide films of 5 nm holes on 8.1 nm centers was achieved with exposure times in the millisecond range, 2 approx. 3 orders of magnitude lower than produced by other technique. The generated oxide films for applying high density memory needs the apparatus to read/write using oxide films. This report describes an E-beam addressed, high speed, mass memory system that would be capable of 10(exp 12)-10(exp 14) bits with a data transfer rate about 106 bits per seconds. The development of the storage medium and the proper electron beam optics system for the mass memory system is a most crucial element of E-beam generated ultrastructures. jg