J. F. Ziegler

The Stopping and Range of Ions in Solids

The stopping and range of ions in matter is physically very complex, and there are few simple approximations which are accurate. However, if modern calculations are performed, the ion distributions can be calculated with good accuracy, typically better than 10%. This review will be in several sections: a) A brief exposition of what can be determined by modern calculations. b) A review of existing widely-cited tables of ion stopping and ranges. c) A review of the calculation of accurate ion stopping powers.

The Stopping and Range of Ions in Matter

The purpose of this chapter is to review the calculation f the stopping and the final range distribution of ions in matter. During the last thirty years there have been published scores of tables and books evaluating the parameters of energetic ion penetration of matter. Rarely have the authors of these reference works included any evaluation of the accuracy of the tabulated numbers. We have chosen to show the development of ion penetration theory by tracing how, as the theory developed through the years, various parts have been incorporated into tables and increased their accuracy. This approach restricts our comments to those theoretical advances which have made significant contributions to the obtaining of practical ion stopping powers and range distributions. The Tables reviewed were chosen because of their extensive citation in the literature.

Terrestrial cosmic rays

This paper reviews the basic physics of those cosmic rays which can affect terrestrial electronics. Cosmic rays at sea level consist mostly of neutrons, protons, pions, muons, electrons, and photons. The particles which cause significant soft fails in electronics are those particles with the strong interaction: neutrons, protons, and pions. At sea level, about 95% of these particles are neutrons. The quantitative flux of neutrons can be estimated to within 3{times}, and the relative variation in neutron flux with latitude, altitude, diurnal time, earth`s sidereal position, and solar cycle is known with even higher accuracy. The possibility of two particles of a cascade interacting with a single circuit to cause two simultaneous errors is discussed. The terrestrial flux of nucleons can be attenuated by shielding, making a significant reduction in the electronic system soft-error rate. Estimates of such attenuation are made.

IBM experiments in soft fails in computer electronics (1978–1994)

This review paper has described the experimental work at IBM over the last fifteen years in evaluating the effect of cosmic rays on terrestrial electronic components. This work originated in 1978, went through several years of research to verify its magnitude, and became a significant factor in IBM`s efforts toward improved product reliability.

New precision technique for measuring the concentration versus depth of hydrogen in solids

A method for the measurement of the concentration of hydrogen versus depth in solids using the 1H+15N resonant nuclear reaction is discussed. This method has a typical depth resolution of 50–100 A, can be used to a depth of several microns, and can measure hydrogen in concentrations of one part per thousand or greater.

Effect of Cosmic Rays on Computer Memories

A method is developed for evaluating the effects of cosmic rays on computer memories and is applied to some typical memory devices. The sea-level flux of cosmic-ray particles is reviewed and the interaction of each type of particle with silicon is estimated, with emphasis on processes that produce bursts of charge. These charge pulses are then related to typical computer large-scale integrated circuit components and cosmic-ray-induced errors are estimated. The effects of shielding (such as building ceilings and walls), altitude, and solar cycle are estimated. Cosmic-ray nucleons and muons can cause errors in current memories at a level of marginal significance, and there may be a very significant effect in the next generation of computer memory circuitry. Error rates increase rapidly with altitude, which may be used for testing to make electronic devices less sensitive to cosmic rays.

Stopping of energetic light ions in elemental matter

The formalism for calculating the stopping of energetic light ions (H, He, and Li) at energies above 1 MeV/u, has advanced to the point that stopping powers may now be calculated with an accuracy of a few percent for all elemental materials. Although the subject has been of interest for a century, only recently have the final required corrections been understood and evaluated. The theory of energetic ion stopping is reviewed with emphasis on those aspects that pertain to the calculation of accurate stopping powers.

Quantitative analysis of hydrogen in glow discharge amorphous silicon

We report measurements of the hydrogen concentrations and densities of amorphous silicon films prepared from glow discharge plasmas of silane. Quantitative results are obtained from the resonant nuclear reaction 15N+1H→12C+4He+γ by counting the emitted γ rays. Mass spectrographic analysis of the gases evolved upon heating are also used to estimate the relative hydrogen concentrations for different preparation conditions. Comparisons are given to previously reported infrared absorption results and to electron microprobe estimates.

Terrestrial cosmic ray intensities

Cosmic rays may cause soft fails in electronic logic or memory. The IBM Joumal of Research and Development, Volume 40, No. 1, discussed this complex event in detail. In order to predict electronic fail rates from cosmic particles, it is necessary to know the local cosmic ray flux. This paper reviews the penetration of cosmic rays through the earths atmosphere, and the parameters which affect the terrestrial flux. The final particle flux is shown to vary mainly with the sites geomagnetic coordinates and its altitude. The paper describes in detail the quantitative cosmic flux at one datum (New York City) and then tabulates in an appendix the relative level at other major cities of the world.

Profiling Hydrogen in Materials Using Ion Beams

Abstract Over the last few years many ion beam techniques have been reported for the profiling of hydrogen in materials. We have evaluated nine of these using similar samples of hydrogen ion-implanted into silicon. When possible the samples were analysed using two or more techniques to confirm the ion-implanted accuracy. We report the results of this work which has produced a consensus profile of H in silicon which is useful as a calibration standard. The analytical techniques used have capabilities ranging from very high depth resolution ( ≈50 A ) and high sensitivity (