Ion beam deposition in materials research, NIMB Vol. 37-38, 16-21 (1989) RA Zhur, SJ Pennycook, TS Noggle, N Herbots, TE Haynes, BR Appleton (original) (raw)
Related papers
MRS Proceedings, 1986
The technique of ion beam deposition (IBD) is utilized to investigate low-energy, ion-induced damage on Si and Ge; to study reactive ion cleaning of Si and Ge; to fabricate amorphous isotopic heterostructures; and to fabricate and study the low-temperature epitaxial deposition of 7 4 Ge on Ge(100), 3 0 Si on Si(100), and 74 Ge on Si(100). The techniques of ion scattering/channeling and cross-sectional TEM are combined to characterize the deposits.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 1987
Direct ion beam deposition (IBD) is utilized to deposit isotopic thin films and heterostructures and to achieve high-quality epitaxial growth of 74Ge on Ge(100) and 3°Si on Si(100) at temperatures as low as 400°C. Anomalous damage is observed during IBD at 400 ° and 600°C that results in a band of buffed loops at depths 50 times normal and a defect-free region near the original surface. An unexplained doping effect is reported for epitaxial growth of Si on Si at 20-40 eV, 400°C where high-quality epitaxy occurs on n-type Si but amorphous films form on p-type.
… Symposium Held April 21-23, 1987 …, 1987
A low-energy ion beam deposition system has been developed at Oak Ridge National Laboratory and has been applied successfully to the growth of epitaxial films at low temperatures for a number of different elements. The deposition system utilizes the ion source and optics of a commercial ion implantation accelerator. The 35 keV mass-and energy-analyzed ion beam from the accelerator is decelerated in a four-element electrostatic lens assembly to energies between 10 and 500 eV for direct deposition onto a target under UHV conditions. Current densities on the order of 10 A/cm are achieved with good uniformity over a 1.4 cm diameter spot. The completed films are characterized by Rutherford backscattering, ion channeling, cross-section transmission electron microscopy, and x-ray diffraction. The effects of substrate temperature, ion energy, and substrate cleaning have been studied. Epitaxial overlayers which show good minimum yields by ion channeling (3-4%) have been produced at temperatures as low as 375 0 C for Si on Si(100) and 250"C for Ge on Ge(100) at growth rates that exceed the solid-phase epitaxy rates at these temperatures by more than an order of magnitude.
Nuclear Instruments and …, 1986
Atomic collisions in solids in the 40-200 eV energy range have been studied both theoreticalIy and experimentaIiy to determine the feasibility of the ion beam deposition (IBD) of amorphous and/or epitaxial layers. IBD was first modeled by a rate equation including the target sputtering yield and the ion self-sputtering, range and range straggling. To obtain preliminary values of those parameters, Monte Carlo simulations with TRIMSPUT were used. The surface binding energy (SBE) appeared to be an important parameter of the simulation for sputtering yields under 200 eV. By fitting the SBE with available sputtering data for Ar on Si below 1 keV, a very good agreement waso obtained between simulations and sputtering data of other ion-target combinations. Experimentally, 30Si and 74Ge ions were deposited on Si( 100) at 300 K and 700 K. Cross-section TEM combined with ion scattering and ion channeling showed that IBD can provide very thin (3 nm) though perfectly continuous films with sharp interfaces (<l nm). IBD damage to the substrate saturates as a function of dose, is negligible below 4OeV, and presents an interesting annihilation/long range diffusion behavior as a function of the temperature during irradiation.
Materials Research Society …, 1992
""ABSTRACT Three important effects of low energy direct Ion Beam Deposition (IBD) are the athermal incorporation of material into a substrate, the enhancement of atomic mobility in the subsurface, and the modification of growth kinetics it creates. All lead to a significant lowering of the temperature necessary to induce epitaxial growth and chemical reactions. The fundamental understanding and new applications of low temperature kinetics induced by low energy ions in thin film growth and surface processing of semiconductors are reviewed. It is shown that the mechanism of IBD growth can be understood and computed quantitatively using a simple model including ion induced defect generation and sputtering, elastic recombination, thermal diffusion, chemical reactivity, and desorption. The energy, temperature and dose dependence of growth rate, epitaxy, and chemical reaction during IBD is found to be controlled by the net recombination rate of interstitials at the surface in the case of epitaxy and unreacted films, and by the balance between ion beam decomposition and phase formation induced by ion beam generated defects in the case of compound thin films. Recent systematic experiments on the formation of oxides and nitrides on Si, Ge/Si(100), heteroepitaxial SixGe1−x/Si(100) and GaAs(lOO) illustrate applications of this mechanism using IBD in the form of Ion Beam Nitridation (IBN), Ion Beam Oxidation (IBO) and Combined Ion and Molecular beam Deposition (CIMD). It is shown that these techniques enable (1) the formation of conventional phases in conditions never used before, (2) the control and creation of properties via new degrees of freedom such as ion energy and lowered substrate temperatures, and (3) the formation of new metastable heterostructures that cannot be grown by pure thermal means.""
Ion beam deposition and in-situ ion beam analysis
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 1992
The direct deposition in thin films and the production of very shallow junctions by ultralow energy ion implantation involves the interaction of ions with only the outermost surface layers of a solid. Quantitative structural and composition analysis of the grown or implanted layers requires the use of techniques with extremely high depth resolution. The growth of Si epitaxially on Si (100) substrates prepared by a variety of ion beam and thermal treatments has illustrated the complex radiation effects that occur in the bombardment energy range from 20 to 500 eV. These effects have been studied using medium energy ion scattering in the double alignment mode. With a 50 keV H+ beam, a high resolution electrostatic analyser and incidence and emergence directions aligned with the [111¯] and [3¯3¯1] directions, a depth resolution of 3 Å can be obtained. The effects of ion energy on the structure of grown films and on the damage in the substrate during pretreatment with Cl+ and Ar+ ions will be described.
In our previous work, we investigated the use of ion beam deposition (IBD) to grow epitaxial films at temperatures lower than those used in thermal processing (less than 500°C). Presently, we have applied IBD to the growth of dense (6.4×102 2 atom/cm3) silicon dioxide thin films at 400°C. Through these experiments we have found several clues to the microscopic processes leading to the formation of thin film phases by low energy ions. Using Monte‐Carlo simulations, we have found that low energy collision cascades in silicon have unique features such as a high probability of relocation events that refill vacancies as they are created. Our results show that the combination of a low defect density in low energy collision cascades with the high mobility of interstitials in covalent materials can be used to athermally generate atomic displacements tha can lead to ordering. These displacements can lead to epitaxial ordering at substrate temperatures below the minimum temperature necessary for molecular beam epitaxy (550°C). It can also lead to the formation of high quality silicon dioxide at temperatures well below that of thermal oxidation in silicon (i.e. <850°C). A growth model which we derive from these observations provides a fundamental understanding of how atomic collisions can be used to induce epitaxy or compound formation at low temperatures.
Microstructural evolution during ion beam assisted Deposition
MRS Proceedings, 1994
The advantages of energetic deposition are low temperature processing, oriented or single crystal films, high phase purity, high density and good adhesion to substrates. The time and spatial scales over which the atoms arrange themselves on a surface are not easy accessed experimentally. Therefore, these advantages are customarily verified by ex-situ examination of films after deposition is complete, which gives little information on atomic scale processes that lead to the listed advantages. The addition of energy to the deposition flux effects surface processes that are otherwise only controllable by changing the substrate temperature. Thus, understanding the mechanisms by which energetic atoms alter surface processes in analogy with thermal effects is of paramount interest for optimization of the deposition parameters. This review summarizes the state of knowledge on the effects of energetic ions on film formation. For high quality, defect free films, the energy must be controlled...