About 2 μm thick commercial coatings of TiN on high speed steel substrates were implanted at room temperature with 95 keV carbon to nominal doses between 1 × 1017 and 8×1017 ions cm-2. An ultra-microhardness apparatus (UMIS-2000) was used to measure hardness, and a pin-on-disc machine (CSEM Tribometer) with a sapphire ball was used to measure wear, friction and adhesion. Carbon implantation induced a significant improvement in ultra-microhardness, friction coefficient and wear properties. The surface microhardness increases monotonically by up to 115% until a critical dose φ crit is reached. Beyond this dose the hardness decreases, but remains higher than that of unimplanted sample. A lower friction coefficient and a longer transition period towards a steady state condition were obtained by implantation. An improvement of up to four times in the wear is obtained after carbon implantation. Topology studies with SEM show a change in the mode of wear. The changes in tribomechanical properties are discussed in terms of radiation damage and possible second phase formation.

Analysis of fired rails from electromagnetic railgun indicates gross surface melting near the breach end of the rails. This effect is most likely caused by joule heating and arc erosion. To improve the mechanical behavior of the rail material, alloys of copper, such as Cu-0.6 Nb, has been used in the past with moderate success. More recently another alloy of copper, Cu-18 Nb, has become available. Preliminary metallurgical research in the thermomechanical properties of this latter alloy indicates it could be a candidate for application in EM gun systems. In this effort we have attempted to study the influence of ion implantation on the thermomechanical properties of Cu-12Nb alloy. In a series of experiments, Ta ions have been implanted at an energy range of 100–180 KeV and a dose of 5 × 1016 cm-2. Several analytical techniques such as Rutherford Back Scattering (RBS), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), arc erosion, and microhardness measurements have been done. It has been shown that although there is an improvement in the microhardness of the implanted materials, the ion implantation saturation dose cannot exceed 5 × 1016 cm-2. Furthermore, the RBS data indicate that the implanted Ta resides mostly at a depth of about 200–300 Å from the surface. Results from the SEM analysis of unimplanted Cu-12Nb indicate the Nb has an acicular morphology and is randomly distributed. Results from microhardness measurements of the implanted materials indicate that implantation enhances the microhardness. In another experiment, such as implantation of Ta in an already TiN coated surface, we observed a similar increase in the microhardness value. We speculate that the microhardness improvement of Cu-18Nb or the Ta implanted TiN surface is due to induce compressional stresses near the lenticular (filament) Nb fibers in the Cu-18Nb composite.

Copper and aluminum are extensively used in various parts of the Electromagnetic (EM) Gun systems. Copper is used in the design of the railgun because it has favorable electrical and thermal properties. Aluminum is used for armature and sabot fabrication because of it is light weight and has favorable thermal properties. Extensive degradation of the copper rail and aluminum armature occurs owing to the severe heating and thermomechanical deformation of these components during operation of the EM gun. In this research effort, several modification techniques were used to protect the rail and armature materials from these degradation processes. These include application of Plasma Source Ion Implantation (PSII) and Ion Beam Enhanced Deposition (IBED) . By using these techniques, the copper rails and aluminum armatures were coated with TiN and TaN. Several characterization techniques were used to assess the chemical,mechanical and other properties of these modified surfaces. Optical Microscopy, Scanning and Transmission Electron Microscopy, and Scanning Auger Spectroscopy techniques were also used. Microhardness measurements have also been performed. From the results of this preliminary investigation, it has been concluded that the surface properties of the coated rail and armature materials have been improved and the extent of wear and spark erosion from these surfaces has been reduced.

Copper and aluminum used for rail and armature materials in electromagnetic railgun systems undergo severe degradation during the EM gun operation. The extent of this degradation is especially severe in guns operated at high energy levels or designed for repeated firings. In an effort to improve surface properties of the copper rail, armature, and sabot materials, the technique of metal ion implantation using a vacuum arc ion source has been employed. Preliminary tests have been conducted to identify the best implant species to improve spark erosion resistance, scratch resistance and hardness. The implanted species included Al, Ti, Cr, Ni, Ta, Ag, and W. The implantation energy range and dose varied between 100–180 KeV and 0.4 to 2 × 1017 cm-2, respectively . Several analytical techniques were also used to assess the effect of implanted species. These included Rutherford Back Scattering (RBS), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Microhardness Measurements, Spark Erosion and Scratch Testing. It has been tentatively concluded that Ta and Ni implantation of the copper rail substantially improve wear and inhibit arc erosion. There is also sufficient evidence to indicate that implantation of the aluminum armature with Cr and Ta, involving two stages of implantation, will also improve its mechanical and wear properties.

A new facility is operational at Los Alamos to examine plasma source ion implantation on a large scale. Large workpieces can be treated in a 1.5-m-diameter, 4.6-m-Jong plasma vacuum chamber. Primary emphasis is directed towards improving tribological properties of metal surfaces. First experiments have been performed at 40 kV with nitrogen plasmas. Both coupons and manufactured components, with surface areas up to 4 m2, have been processed. Composition and surface hardness of implanted materials are evaluated. Implant conformality and dose uniformity into practical geometries are estimated with multidimensional particle-in-cell computations of plasma electron and ion dynamics, and Monte Carlo simulations of ion transport in solids.

The feasibility of strength and reliability improvements of Si3N4 through ion implantations has been studied. The approach has been to implant elements that may chemically combine with themselves to form precipitates after appropriate annealing. These precipitates can improve the strength and reliability of ceramics through the introduction of a compressive stress in the implanted surface layer and/or by modifying the fracture originating machining flaws. Sequential implantations of ion pairs of Ti+ and C+, and Si+ and C+ were performed at energies in the range 46 to 175 keV and at doses of 1×1017 cm-2 for each ion species. Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS) and Transmission electron microscopy (TEM) techniques were used to analyze the implanted layer. Strength and reliability were determined from four-point flexure strength measurements. Precipitates of TiN and C were found to form in Ti++C+ and Si++C+ implanted Si3N4 surfaces, respectively. Si++C+ implantation resulted in improvements of both strength and reliability of Si3N4, while Ti++C+ implantations had no effect.

Diamond-like carbon films have been prepared by using dual ion beam sputtering deposition under CH++Ne+ bombardment with energies 50–800 eV. The obtained films possess a smooth surface and an amorphous structure containing some sp3 bondings. DLC films bombarded by low energy CH++Ne+ exhibit the relatively high binding energy and electrical resistivity which are approximate to those of diamond. It is believed that a Mo interlayer between AISI 52100 steel substrates and DLC films brings the films good adhesion. This offers promises to DLC films on bearing steel to perform a stable wearing in much lower friction coefficient (<0.1) under large wear loads (30–90N). Experimentally, low wear coefficients and high anti wear numbers obtained prove that the DLC films indeed possess excellent wear resistance. In addition, the speed or the momentum of friction motion was revealed to exert some serious effects upon the wear resistance of DLC films when the wearing was carried out under very high wear load (> 30 N).

An R&D project of large scale ion beam equipment and processing is being carried out from 1986 till 1994. The project includes R&D of five ion beam systems and three material processes for surface modification. The five equipment R&D projects are:

(1)High current metal ion beam system,

(2)Integrated high current ion beam system,

(3)Ionized multiple beam system with high deposition rate,

(4)High energy ion beam system,

(5)Gas-phase focused ion beam system.

The three materials processing R&D projects are:

(1)Glass surface modification,

(2)Metal surface modification,

(3)Low scattering multilayer film deposition. This paper reviews recent progress on development of the project. This work was conducted in the program: ’Advanced Material Processing and Machining System’ consigned to AMMTRA from the New Energy and Industrial Technology Development Organization, which is carried out under the Industrial Science and Technology Frontier Program enforced by the Agency of Industrial Science and Technology of Japan.

In this paper, the first comprehensive and computationally-efficient two-dimensional model is reported for boron implants into (100) single-crystal silicon with explicit dependence on energy, dose, implant angles, mask height, mask orientation, and rotation of the wafer during the implant. The model and its implementation into SUPREM 4 are described, and where possible, the explicit dependencies are illustrated.

The organic materials of biological samples such as wheat, rice, corn and bean were implanted by nitrogen irons with energy ranging from 35–180 KeV. Biological effects including physiological and genetic variations on these crops were induced by ion implantation. In order to understand the role played by ion implantation, the distributions and the ranges of the implanted ions in biological samples were measured by RBS spectrometry. Theoretical calculations of the ranges were carried out using TRIM program. The results of experimental measurement were found essentially the same as the calculated values. The mechanism of the biological variations induced by ion beams is discussed.

Ion implantation in semiconductor devices frequently leads to a substantial wafer surface charge build up. Control of this charge during high current implantation is a major process issue, as it may affect the yield and reliability of thin dielectric layers. In addition, the charge build up may affect the ion beam resulting in a non-uniform implant and a reduction in device yield. Control of a specific machine parameter, that will give the charge condition of the ion implanter will enable to neutralize the charge build up.

In this study, Disk Current Monitoring (DCM) is shown to be a reliable method for monitoring the Electron Shower (ES) performance in real time. A correlation was found between DCM level and yields, and between DCM level and breakdown voltage, as well as different maintenance activities regarding me ES. A simple 5 steps method is described to achieve a reliable, real time charge monitor, to insure operation within the “High Yield Range”.

In this paper is reported a new approach for the Monte Carlo simulation of deeply-channeled implanted profiles in single-crystal silicon which has greatly improved efficiency. This approach has been successfully implemented in the UT Monte Carlo code (UT-MARLOWE). A time savings of up to 212X has been observed with a 4-stage simulation. A simulation of arsenic implants with 15 keV implant energy typically takes about 12 minutes on a workstation.

Extensive studies of the mathematical and physical aspects of the interpretation of NRA spectra began in the mid - 1980s. A large amount of work [1-3] in this field was done by G.Amsel's group. Various physical effects accompanying the beam - target interaction were analysed and their influence on the accuracy of the concentration profile was evaluated. To solve the direct problem, a program which is now widely used was written on the basis of that study.

Since the introduction of the G1500 ion implanter, the use of tandem accelerators in production ion implantation systems has become well established. However, the beam currents which are attainable at present at low energies (< 200 keV) are suitable for only low and low-end medium dose implants. An approach to increase low energy beam currents in d.c. tandem accelerators is presented. Specifically, the use of negative ions which have been generated in the injector are transported to the end station and implanted into the wafers. In this work, beam current measurements performed using the G1500 system are presented for the typical semiconductor dopants. System changes which are necessary to accomplish implants with negative ions are discussed. A comparison of sheet resistances and uniformities measured with both positive and negative ions at the same energy and from the same G1500 system are presented. SIMS profile measurements of implants with both positive and negative ions at the same energy are also presented.

High-resolution x-ray triple axis diffractometry was used to characterize damage recovery in gallium arsenide implanted with gallium or indium ions, and co-implanted with carbon ions. From reciprocal space mapping around the (004) reciprocal lattice point, the evolution of residual strain and the lattice plane tilt induced by the ion implantation and annealing processes were analyzed. The lattice damage in implanted gallium arsenide is dependent on the dose and ion type; annealing subsequently alters the structural properties of the material. For example, In/C co-implanted gallium arsenide shows a greater amount of residual damage as compared to Ga/C co-implanted gallium arsenide after rapid thermal annealing at 885 °C for 5 seconds. For a given Group III ion / C co-implant, we observe the highest p-type activation when the Group III ion and C implant doses are the same. Increasing the Group III ion dose reduces the material quality and has a concomitant negative effect on the electrical properties of the material. These results suggest that reciprocal space maps can provide insight into the relationship between the structure and properties of implanted compound semiconductors.

Photon and proton channeling have been observed in LiNbO3:Fe crystals which have holographically recorded electric field gratings. An analogy between photon and proton channeling is developed and compared with the experimental results.

An electric field has been imposed on single crystals of pure and doped LiNbO3 during bombardment with 1.03 MeV protons and 2.1 MeV alpha particles. Simultaneous (p,p), (p,α) and (p,p'γ) channeling between the crystal planes showed that the channeling is less pronounced when an electric field of 106 volts/m is imposed perpendicular to the incident ion beam direction and to the channeling planes in the crystal. The results obtained are discussed and compared to the effects due to the fringe field outside the crystal, differential cation-anion movement, movement of interplanar impurities, the piezoelectric strain and movement or creation of crystal defects on ion channeling.

Laser modulated thermoreflectivity, also called thermal wave technology, has been used in recent years to monitor ion implantation dose by monitoring the damage due to implantation. The thermal properties which are affected by lattice perturbations and other crystal imperfections are tracked by this technique. A gauge capability study was performed on the Thermawave TP300 for monitoring ion implantation of GaAs wafers. The results are presented. In order to determine the sensitivity of the technique to changes in dose, a matrix of GaAs and Si wafers was measured. During this study a downward trend was observed in the repeatability of our results. It is shown that damage to a sample during implantation will relax to a certain degree at room temperature. This damage relaxation can take up to 80 hours at room temperature and can be observed using thermal waves. It is shown that “hot wafer decay” follows a logarithmic decay which is indicative of a diffusion process. At 180°C the decay lasts less than 1 minute which indicates that the defects causing this phenomenon have a low activation energy.

Three dimensional visualization of ion channeling spectra was obtained by computer graphics in order to observe the crystalline quality and the strain state of thin films. Pure (100)Si and Si1-xGex (x=0.10, 0.18) layers, epitaxially grown on (100)Si substrates, were channeled along the <110> crystal axis with the 2 MeV He++ ion beam in a UHV target chamber. The data were interpolated using a standard bicubic tensor product B-spline surface with uniform knot sequences in x and y directions. With this modeling technique we have shown the orientation of the major planes in a diamond crystal and the angular displacement of the Ge signal in the SiGe epilayer relative to the Si substrate signal due to the presence of tetragonal distortion in the epilayer.

Silicon-On-Insulator (SOI) technology [1-4] has been shown to have significant performance and fabrication advantages over conventional bulk processing for a wide variety of large scale CMOS IC applications. Advantages in radiation environments has generated significant interest in this technology from military and space science communities [5,6]. Possible advantages of SOI technology for low power, low voltage and high performance circuit applications is under serious consideration by several commercial IC manufacturers [7,8].