A novel technique for high speed X-ray double crystal rocking curve analysis of epitaxial layers is described. It employs specimen rotation about an axis almost normal to the Bragg planes in order to optimize Bragg plane tilts. Very rapid set-up is possible by peak searching using this rotation axis rather than the standard ω scan. A rotation stage suitable for a Bede Scientific Instrument Model 6 diffractometer is described and its performance assessed. Experimental and theoretical values of the shift in centroid of the ω scan rocking curve as a function of rotation angle are in excellent agreement.

The widespread use of through-oxide implants in Si-MOS technology has prompted many studies to characterize the behaviour of oxygen recoiling from the passivating SiO2 layer into the Si substrate. These studies have given support for the idea that an anomalous formation of defects, which alter the profile of the implanted impurity and the mobility of the free carriers, is connected with the oxygen recoils.

This paper discusses the results of recent experiments at Stanford Synchrotron Radiation Laboratory (SSRL) and Hamburger Synchrotronstrahlungslabor (HASYLAB) which were designed to explore the feasibility of using synchrotron radiation in high-resolution, computerized, critical-absorption tomography. The results demonstrate that it is possible, using absorption-edge differencing, to identify adjacent elements in the periodic table with high sensitivity. Furthermore, by using the fine structure in the absorption spectra, it is possible to distinguish between regions of different chemical states. Methods of using synchrotron radiation for high-resolution, three-dimensional chemical-state mapping in small samples are discussed.

We report measurement of Bragg intensities obtained from an Fe3Al(110) single crystal under the condition of total reflection. It is demonstrated that depth-resolved near-surface atomic correlations can be achieved by the independent control of both ocurring grazing angles.

Near-IR absorption mapping has been used for polished GaAs wafers (0.5 mm thick) cut at intervals along the seed-to-tail length of (100)-oriented LEC-grown semi-insulating (SI) ingots. Some 2000 points are measured, point by point, over a wafer's area, usually near 1.0 μm for EL2 mapping, and near 1.4 μm for observation of stress interferograms. For the results presented here (high pressure LEC crystals from a major commercial supplier), stress maps display the fourfold symmetry predicted in thermoelastic models. The EL2 maps do not necessarily display the same symmetry, especially for wafers from near the tail end of an ingot.

The silicon-oxygen chemical bond is the key building block for many of the dielectric thin films used in silicon MOS technology. High quality thermal silicon oxides serve as gate dieletrics. CVD silicon oxides, produced by a variety of deposition processes, are used as interlayer dielectrics and as passivating layers. These films may be stoichiometric or nonstoichiometric, or doped with boron and/or phosphorus to provide the most desirable film properties.

Bandshape analysis of the Fourier Transform Infrared (FTIR) spectra of these films can provide information on the chemical bond strength, the homogeneity, and the optical dielectric function of various glasses. Spectral features are found to change characteristically, depending upon deposition conditions, subsequent processing (densification), the influence of dopants, stress, and the effects of overlying films. In comparing films [Bposited under different conditions, the primary Si-O stretching mode peak position shifts over a 30cm-1 range and has a FWHM that varies by as much as 50%. The FTIR technique can routinely resolve peak shifts in glasses as small as 2 cm-1, sufficient to detect the differences observed due to deposition or processing.

In this paper we describe Fourier transform Photoluminescence (FTPL) spectroscopy and report the first application of this technique to the analysis of semiconductor silicon. Two applications of FTPL spectroscopy to silicon are discussed. The first application is to quantitative trace analysis of the Ill-V impurities B,P, As and Al in silicon. Both high purity and compensated silicon have been studied and PL features correlated to the concentrations of the individual impurity species present. The capability of analysing B, P, As and Al at part per trillion atomic concentrations in silicon is demonstrated. In the second part of this paper, application of FTPL to the analysis of thermally induced microdefects in silicon is discussed. Defect band intensities are shown to be proportional to the concentration of interstitial oxygen precipitated in the case of plate precipitate morphology. In these two applications, FTPL is shown to uniquely provide both residual impurity and microdefect information of as grown and processed silicon.

It is known that dislocations and EL2 clusters participate in infrared transmission images. Optical quenching of the typical cell patterns at low temperature also charge EL2 with contributing to images. A point yet is not clearly established: such optical contrast could originate in a quantum absorption process or as well in a scattering of the photons. This paper aims at showing that both optical processes are likely to occur in most of the GaAs SI samples and that the two phenomenons can be considered as localy correlated. So monitoring EL2 center density by optical “absorption” could be a trap for the unwarry.

We have developed general algorithms for interpreting X-ray fluorescence data from single and multilayer metal films to yield precise values for both thickness and composition. As an example, the precision for replicate analyses of a Permalloy sample was measured to be 0.07 weight % Ni (1σ). The thickness was measured to be 1.387 ± 0.005 microns, a 1σ precision of 0.3% relative. Several examples will be presented.

The fundamental parameter algorithms are quite general and are capable of dealing with variable compositions in each of the films in a multilayer stack. The only restrictions are that: 1) Each element analyzed must appear only once in the films or substrate, and 2) The signal from each element is not obscured by that of another element. The accuracy and precision of the measurement is improved if a substrate signal is observed.

The sensitivity of spectroscopic ellipsometry data to multilayer model parameters is shown to be a strong function of the angle of incidence. A quantitative study for a GaAs-AlxGa1-xAs-GaAs structure shows that maximum sensitivity to layer thicknesses and ternary composition occurs near the wavelength-dependent principal angle. These results are verified by experimental measurements on two MBE-grown samples. Moderately high doping levels in the ternary layers are also found to strongly affect the data at photon energies below the ternary bandgap. Null ellipsometry measurements at only two wavelengths are sufficient to determine layer thicknesses.

Laser beam induced current images (LBIC) of polycrystalline silicon and liquid encapsulated Czochralski (LEC) GaAs are observed with a new scanning optical fiber microscope (SOFM), which utilizes an optical fiber as a mobile light source. In this system, fine optical probing with the beam diameter less than lm is achieved without requiring severe mechanical precision. A variety of light sources are employed to reveal different defect species. The distribution of deep levels in LEC GaAs is visualized with extrinsic photo-excitation by using a Nd:YAG laser.

Composition profiles of interdiffused epitaxial Hg1-xCdxTe have been determined using interband E1 microreflection spectroscopy. The technique provides a rapid, noncontacting method of compositional analysis using the near UV-visible spectral range. It measures alloy composition (x-value) over a sampling surface as small as 5 μm square to an accuracy better than 0.01. Profiles are measured by repeatedly etching small sampling wells in discrete steps. Profiles were measured on epitaxial Hg0.7Cd0.3Te films grown on Hg0.8Cd0.2Te substrates with and without extended anneal treatments. They were also calculated by numerically solving the diffusion equation using published composition dependent diffusion coefficients. The experimental and theoretical profiles are compared graphically. Calculated as-grown and annealed interdiffusion widths (9 and 13μm, respectively) differ from measured values by less than 15%. It is shown that Hg and Cd interdiffusion during both the growth and subsequent anneal is responsible for the observed interface widths.

The laser microprobe mass analysis (LMMA) technique currently finds extensive application in the qualitative microanalysis of a wide range of materials. These microanalytical applications include the analysis of polymeric materials [1], semiconductors [2] and particulate samples [3]. These qualitative analyses have repeatedly demonstrated the analytical ability of this technique for producing rapid, elemental, isotopic and, in some cases, molecular characterization of these types of materials. The development of quantitative or semi-quantitative analytical methodologies is the goal of any analytical technique and rather extensive investigation of the quantitative capabilities of the laser microprobe technique have been pursued since the initial development of this technique. These investigations have centered on developing appropriate microanalytical standards [4], characterizing the pertinent physical and chemical processes occurring during high power laser irradiation of materials [5] and modeling the nature and extent of the ionization produced with physically reasonable models [6, 7]. To date, these quantitative studies have generally provided good analytical methods and results and, although the number of quantitative analyses of materials systems have been rather limited, the results do provide sufficient encouragement to pursue further quantitative studies with this technique. In this paper, we discuss the results obtained in a laser microprobe analysis of phosphosilicate glass (PSG) standards in which the quantitative capabilities of the technique for the determination of the phosphorous content of PSG glasses were evaluated. The results of this analysis were compared to those produced from a secondary ion mass spectrometry (SIMS) analysis of these PSG standards. We have also evaluated the in-depth profiling capability of the laser microprobe technique and demonstrate this capability with a depth profile of a 11B implant into Si. Finally, we present preliminary data obtained from a new modification to the basic laser microprobe technique in which the conventional laser system is employed to ablate the sample material and a second laser pulse ionizes the neutral-components in the vapor plume produced by the ablation laser. This two laser configuration of the laser microprobe promises to improve the sensitivity and reproducibility of this microanalysis technique.

Grazing angle configurations improve the depth resolution of Rutherford Backscattering Spectrometry (RBS) because the path length of scattered particles is geometrically increased. But in the limit of very grazing angles the resolution degrades due to the finite detector acceptance angle and low angle forward scattering of the beam, considerations which are not present in near-normal incidence geometries. The forward scattering, for example, worsens the depth resolution approximately as the square of the depth, rather than the familiar square root dependence of energy straggling. We present a simple computational scheme which predicts the depth resolution in any target as a function of scattering depth, beam energy, and the grazing angle. The calculations are simpler than previous studies because we use analytic expressions in place of numerical inputs without loss of accuracy. The results lead directly to an optimum depth resolution. We find good agreement between the predicted resolution and measurements on thin silicon dioxide and amorphous silicon films. Finally, we calculate the resolution expected with the use of ion beams heavier than He+, and find improved near surface depth resolution if a low noise detector is used.

Thermally activated metallurgical reactions between GaAs and various metals of potential importance in contact structures were studied using Heavy Ion Rutherford Backscattering Spectrometry (HIRBS). The improved mass resolution obtained with heavy ions (160) as projectiles for backscattering measurements facilitated the identification of the various intermetallic compounds formed on GaAs. The metal/GaAs systems investigated in this study included Pt/GaAs, Pd/GaAs, and Ni/GaAs. Three different binary compounds were formed in the Pt/GaAs system during annealing. Complete reaction between 1200Å of Pt and GaAs was observed after annealing at 500°C for 20 min. Reactions in Pd/GaAs and Ni/GaAs systems were, however, very different from that of Pt/GaAs. Both Pd and Ni formed ternary compounds with GaAs. Detailed information on the various compound compositions of the three systems as measured by HIRBS is presented. Comparisons of results on similar systems obtained by using other analytical techniques are discussed.

The ratios of the stopping cross sections of deuterium ions in titanium and zirconium deuteride films to those in the pure metals have been determined at incident deuteron energies from 300 keV to 2.0 MeV. These ratios are evaluated from measurements of the yields of deuteron elastic scattering in the deuteride films and in films of the pure metals. Although the absolute stopping cross sections cannot be evaluated from the measurements, use of the Brice yield equation allows the ratios of the cross sections in the deuterides to those in the pure metals to be determined. Significant deviations from Bragg's rule are found and these results are in general agreement with recent measurements at lower deuteron energies (40–200 keV). These measurements represent some of the largest deviations from strict additivity of stopping powers yet observed.

A beam of 2 MeV He+ ions with a diameter of 2 microns was used to perform Rutherford backscattering (RBS) and particle induced x-ray emission (PIXE) analysis on large residual defects formed by high dose arsenic (As) ion implantation and furnace annealing. Research results concerning contamination in implanted silicon wafers generated by primary beam sputtering, inadequate wafer transport system, and other technological factors are presented.

A 700 keV proton beam was used to induce the emission of X-rays in a single crystal copper target. The X-rays are diffracted inside the target, giving rise to a large number of lines, which were recorded on photographic film. The presence of certain lines and the absence of others, as well as the variable intensity along the lines, are explained qualitatively with a kinematical approach.

Channeling contrast microscopy with a He+ microbeam has been employed to measure 3-dimensional damage distributions and impurity profiles in ion implanted laser annealed silicon. Refinements to the technique are described, involving construction of a precision goniometer to allow accurate orientation of the microbeam with respect to micron-scale- sample features. We have found that indium diffusion in amorphous silicon is significantly less for laser annealing than with lower temperature furnace annealing. Lateral variations in the extent of crystal growth have also been observed across laser irradiated areas less than 100μm.

The technique of accelerator mass spectrometry has been used extensively in recent years as a method for detecting low levels (< 1 part per trillion atomic) of radioactive isotopes in solid materials. The technique consists of a Secondary Ion Mass Spectrometer (SIMS) system in which the conventional mass spectrometer has been replaced by a particle accelerator. We have applied this method to the study of stable elements, primarily semiconductor dopants, using the Univ. of Arizona tandem accelerator mass spectrometer. The use of tandem accelerators allows molecular interferences to be removed due to dissociation of the molecules. Particle energies of several MeV are produced, and energy spectroscopy removes the background due to scattered particles, detector noise, etc. to provide positive particle identification. The current detection limits (-10 parts per billion atomic) are primarily due to ion source contamination and their origin is discussed. Removal of this contamination will allow parts per trillion level detection of stable elements.