The surface segregation of a Ni-Cr alloy used for commerciel heating elements hps been examined with a scanning Auger Microprobe (SAM) and other electron spectroscopy. A variety of sample surfaces prepared by different ways, including fracturing, mechanical polishing, electrochemical polishing, annealing, oxidation and their combinptions were investigated.

Results showed that on the surface treated with mechanical polishing followed by oxidation, a continuous, hichly chromium-enriched layer would be formed in a few minutes. Three factors, i.e., mechanical polishing, oxygen environment and temperature, have been found all necessary to make this Cr enrichment happen rapidly.

Taking the advantage of high spatial resolution of AMH, other experimentol facts have been obtained by comparing SFM image and Auger map. First, the Cr segregated at the area where abrading trace (about few micrometers in width) existed. Second, during the oxidation process at early stage Cr war enriched at the arrin boundaries and soreaded laterally.

These results indicate that Cr as diffusing thru the crain boundaries to the surface and the process of mechanical nolishing played, the role for increasing a large number ofcrain boundaries. The chemical driving force of oxygenalso promotes the diffusion unto at a relatively low temperature so is to complet- the orocess in a short period.

The effects of the presence of surface oxides and oxygen incorporated in deposited Ni films on intermixing and compounding at Ni/GaAs(100) interfaces was investigated with Auger sputter profile analysis. The Ni/GaAs structures were heated in vacuum with a high intensity incoherent lamp. Chemical changes and compound distributions were extracted from profile data by factor analysis of the Auger peaks. Diffusion coefficients for Ni at different temperatures were obtained from profile concentration gradients. The results showed that Ni diffusion was faster and activation energy lower for clean versus oxide covered GaAs substrates. Without the presence of oxygen, Ni2 GaAs readily formed at 300°C while with oxygen, the formation of Ni-Ga and Ni-As compounds prevailed over the formation of a distinct Ni2 GaAs layer.

In a lattice-matched <100> InP/Ga0.47In0.53As/Al0.48In0.52As system used for modulation-doped field effect transistors (MODFETs), low resistance ohmic contacts to the two-dimensional electron gas have been fabricated using alloyed NiGeAuAgAu metallization. In this work we examine the use of Auger electron spectroscopy (AES) and wavelength dispersive x-ray spectroscopy (WDX) analyses for studying the metal-semiconductor interactions and their correlation with measured ohmic contact resistance.

Experimental observations of the surface oxide chemistry of GaAs are reported for various commonly used chemical surface preparations. Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), and ellipsometry were employed to obtain information regarding the stoichiometry, depth distribution, and oxide growth kinetics of thin surface oxides. Previous observations of the segregation in depth of Ga and As oxides are corroborated. Arsenic oxides tend to be found near the surface while Ga2O3 is found near the GaAs-oxide interface. The presence of elemental As was frequently detected at this interface, as well. Surfaces essentially free from oxide are shown to be produced by certain chemical treatments, and the state of the surface in the solution is inferred. It is shown that the GaAs surface oxide stoichiometry can undergo several changes in a short time when exposed to water and air. In addition, the characterization of the oxidation of GaAs by ozone in the presence of intense ultraviolet illumination is reported. The oxide primarily consists of Ga2O3 and exhibits an interesting growth kinetics: the thickness of the oxide proceeds at first linearly, then logarithmically, then parabolically. This behavior is explained in terms of various mechanisms which are dominant at different thicknesses of oxide.

This paper describes how secondary ion mass spectrometry can be used effectively in semiconductor device materials and process development. A short overview of the experimental technique is given followed by applications in the following areas:

1) Basic research

2) New Process Development

3) Trouble-shooting current processing

4) Analysis of competitor's devices.

Thermal oxide layers of different thickness (T = 3.5–18 am) covering polycrystalline aluminium sheets were investigated by dynamic SIMS in an ion microscope. Depth profiles of major elements (Al, O), segregated impurities in the oxide layer (Li, Na, Be, Mg) and implanted 18O were recorded for different operating conditions : energy, incident angle, chemical (Ar+ or O2+) and isotopic (16O2+ or 18O2+) nature of the primary beam and oxygen jet to saturate the surface.

The main results are:

- the shape of the depth profiles is very sensitive to operating conditions : the best depth resolution is obtained at low energy (2.5 keV) and the minimal distorsion with an O2 jet, even under O2+ bombardment. Deconvolution would be necessary to deduce the true depth profiles.

- a tremendous enrichment (103 – 104) of the oxide to the Al bulk is observed for Li, Na, Be and Mg via an efficient diffusion mechanism during heat 425°C. Their depth distribution within the oxide layer is heterogenous with surface enrichment for Li and Na and sub-layer (towards the oxide/metal interface) for Be lateral distribution below the interface is also heterogeneous e.g. at the grain boundaries for Be and Na.

- the depth profile of implanted 18O+ versus operating conditions and oxide thickness gives direct information on the dynamic oxidation of Al induced by O2+ sputtering in the first 20 nm.

Secondary Ion Mass Spectrometry, Scanning Auger Microscopy, and Rutherford Backscattering Spectroscopy have been used to study a buried oxide structure on silicon formed by high dose implantation. All these surface analytical techniques give useful information about the oxygen distribution in the buried oxide structure. The difficulties in these techniques have also been assessed.

The primary ion column of a secondary ion mass spectrometer (Cameca IMS 3f) has been used as an ion implanter to prepare calibrated standards, In situ for quantitative SIMS analysis, with an accuracy better than 10%. The technique has been used to determine oxygen concentrations in contaminated TiSi2 films by implanting a reference level of 18O into a portion of the film.

Application of SIMS to ceramics is a complicated but rewarding technique for characterization. The variable composition, hardness and insulating nature of these materials render spectra interpretation complex. Basic data reduction procedures from graphical data collection are presented along with spectra from SIMS applied to a glass frit, magnesium sialon, silicon and PTCR barium titanate.

SIMS-measurements permit a direct determination of the hydration depth of cement particles from the depth profiles of various elements. Furthermore, surfactants containing an aromatic ring system can be analysed qualitatively and quantitatively using the SIMS-intensities of characteristic aromatic fragments. In addition, a new model for the evaluation of SIMS-spectra of oxidic materials is proposed.

Depth profiling is becoming a common method of determining composition gradients for those research facilities that have access to SIMS. The problems with this procedure are briefly discussed but well referenced for those interested in using the technique. Spectra for application of depth profiling to a tantalum pentoxide layer on tantalum, silicon implanted in silica, preferential sputtering of niobium and surface treated lithium alumina silicate glass are presented.

Sputter Initiated Resonance Ionization Spectroscopy (SIRIS) is a technique being developed by Atom Sciences, Inc. to perform ultrasensitive elemental analysis of materials. SIRIS uses sputtering to atomize a solid sample and resonance ionization (RIS) to selectively ionize an element of interest. The SIRIS technique is capable of detecting impurities at the 0.1 ppb level (5 × 1012/cm 3) in a routine analysis time of 5 minutes. RIS and the SIRIS technique are briefly reviewed. We report a detection efficiency for SIRIS of 2 ppb sensitivity and recent results are given for standard well-characterized samples of boron-doped silicon. Current progress is described for the development of depth profiling and the analysis of silicon in gallium arsenide. The SIRIS detection of silicon in standard reference materials certified by NBS is presented.

SIMS microprobe analysis using a liquid metal ion source (LMIS) for the primary ion probe can give fast, sub-micron resolution, chemical imaging of matrix and trace elements. The high brightness and small source size of the LMIS is vital for this high performance. Using a new 30kV gallium ion micro-probe a spatial resolution of 50nm can be achieved with a probe current density in excess of 1 A/cm2. A newly configured SIMS instrument is described which incorporates either a gallium or caesium ion probe as well as a duoplasmatron for ultimate sensitivity and depth profiling performance. For small area, high spatial resolution, depth profiling a raster-scanned ion micro-probe is ideal. A quadrupole mass spectrometer gives a mass range of 1–800 or 2–1200 amu. Examples are presented of up to 50nm resolution SIMS imaging with both positive and negative secondary ions and up to 50nm resolution ion induced secondary electron imaging of a wide variety of samples including superconductors, steels, alloy fractures, optical fibres, integrated circuits, catalysts, polymers and biological specimens. The recent addition of framestore to the system has enhanced the imaging capability, allowing secondary electron and several different secondary ion images of a sample to be overlaid in contrasting colours.

Some applications of spark source mass spectrometry are given showing that this technique, often considered as suitable for bulk analysis only, can also be used for the determination of impurities in thin layers and for in-depth profiling in rather thick samples.

Secondary ion mass spectrometry, in addition to its applications in surface- and in-depth analysis, can successfully be applied to quantitative analysis when using the matrix ion species ratio as an environment sensitive indicator, or when using the isotope dilution method.

Secondary ion mass spectrometry (SIMS), Auger spectroscopy, and transmission electron microscopy (TEM) were applied to study Au, Cu, Ti, Ti-W, Cr, Al-Cu, and Al metal films deposited on both Si and ceramic substrates.

SIMS analysis of as-deposited metal films was used to characterize impurity levels, both metallic and gaseous, incorporated during deposition. The results revealed that the levels varied under generally accepted deposition conditions. As-deposited and annealed films were examined with SIMS, Auger, and TEM to study interdiffusion, grain growth, and impurity segregation as a function of processing conditions. Metallic impurities were observed to modify Au/Ti interdiffusion. Large variations in residual H, C, O, and N were observed in as-deposited Al and Al-Cu films.

Hydrogen, incorporated during deposition of Ti films, was observed to redistribute after thermal annealing in N2 or thermal cycling in forming gas (N2-10% H2). Samples thermally cycled in forming gas absorbed additional H into the Ti layer. SIMS/ion imaging was used to study the incorporation and segregation of H. Differences in H behavior were observed to be dependent upon metal structure, composition, and substrate material.

Every new generation of metal/oxide/semiconductor (MOS) technology has achieved higher densities and switching speeds. In order to match these characteristics of MOS circuits, a metallization which has a low resistivity, has electrical and chemical stability, can withstand high-temperature processing and can be manufactured relatively easily and reliably is needed. These requirements make the refractory metals a suitable if not ideal choice [1,2]. However, there has been some question as to the reliability of processing during silicide formation when using refractory metals. When the metallization is used to form self-aligned silicide structures over heavily doped source and drain regions, it is crucial to understand the subsequent behavior of the dopant during the processing period. Whereas others have studied different aspects of dopant redistribution [3–8], we report in this paper a systematic study of the electrical, structural, and elemental properties of titanium silicide formation on arsenic implanted silicon as a function of implanted dose and processing temperature.

The properties of selected dopants in liquid-phase epitaxial (LPE) layers of HgCdTe have been studied using secondary ion mass spectrometry (SIMS), Hall-effect, and capacitance-voltage (C-V) measurements. The layers were grown from Hg-rich melts on {111}-oriented CdTe and CdZnTe single-crystal substrates. Diodes, for the C-V measurements, were homojunctions formed by ion implantation or heterojunctions formed by the growth of a second layer on the base layer. Dopant concentration distributions in both single- and double-layer structures were characterized by SIMS and C-V measurements. The dopant profiles measured by SIMS were quantified using relative sensitivity factors calculated from ion implanted impurity profiles measured on standard reference samples. Using specialized SIMS techniques, such as molecular ion spectrometry, As concentrations as low as 2 × 1015 cm−3 have been measured. In the HgCdTe:In/HgCdTe:As system minimal dopant interdiffusion is observed in SIMS profiles. The growth of the second layer has insignificant effect on the As distribution in the base layer, and C-V data indicate that the electrical properties change only slightly. Carrier types and concentrations were determined by Hall effect and C-V measurements. Good agreement between dopant concentrations and carrier concentrations was observed, indicating 100% activation of the dopant atoms, for all dopants studied. Examples of implant calibration profiles, dopant concentration distributions, carrier concentration vs temperature measurements, and 1/C2 vs V data are presented, along with graphs and tables comparing dopant profiles with electrical properties.

The hydrogen content in thin film silicon:hydrogen alloy material has been measured by five techniques: 15N nuclear resonance reaction analysis, secondary ion mass spectrometry, infrared spectroscopy, nuclear elastic scattering spectroscopy, and Rutherford backscattering spectroscopy. NRA and SIMS data agree most closely in this study, although SIMS data from three of four laboratories are considerably scattered. The hydrogen content of TFS ranges from 18% at a deposition temperature of 150°C to 10% at 250°C. It varies little, if any, with thickness. Some advantages and disadvantages of the five techniques are discussed.

The incorporation of nitrogen and hydrogen during nitridation of SiO2 was studied over the temperature range of 800–1000°C and for ammonia pressures of 1, 5 and 10 atm. The nitrogen content of the nitrided films was determined with Rutherford backscattering spectrometry. Nitrogen in-depth profiles were obtained applying Auger analysis combined with ion-sputtering. Hydrogen profiles in the films were measured using nuclear reaction analysis. Both the nitrogen and hydrogen incorporation were found to increase with temperature in this range. A higher ammonia pressure primarily increases nitridation of the bulk of the oxide films. Depending on the nitridation conditions up to 10 at.% of hydrogen may be incorporated. As distinct from the nitrogen profiles, the hydrogen in-depth profiles are essentially flat. The concentration of hydrogen in the films, however, was always found to be smaller than that of nitrogen : measured H/N ratios varied between 0.09 and 0.85, the smaller values being obtained for the thinner oxides and higher nitridation temperatures. The model previously postulated to explain the nitrogen incorporation during atmospheric nitridation of SiO2 proves to be valid at higher pressures as well. By considering the role of OH as reaction product of the nitridation process, the hydrogen results can be accommodated within the same concept. The model predicts a low H/N incorporation ratio for a thin surface and interface layer and a substantially larger ratio for the bulk of the film. If this prediction is correct, which seems to be indicated by the etch-rate behaviour of the nitrided oxides, then this would have considerable importance for the electrical properties of this material.

Silicon oxynitride films with various O/N concentration ratios were deposited in a Low Pressure Chemical Vapour Deposition process from SiH2Cl2, N2O and NH3 or ND3. The resulting films were analysed with respect to their chemical compositions using a number of high energy ion beam methods. The results of the analysis are related to the growth kinetics. It is suggested that the SiH2Cl2 decomposes more difficult on growth surfaces which contain more oxygen. The effect is attributed to the larger electronegativity of oxygen compared to nitrogen.