Ion Yield, Sputter Rate, and Sims Matrix Effects in Quantitative Analysis of (AlxGa1−x)0.5N0.5

1998 ◽  
Vol 510 ◽  
Author(s):  
D.L. Lefforge ◽  
Y.L. Chang ◽  
M. Ludowise ◽  
E.L. Allen
Keyword(s):  
Aluminum Gallium Nitride ◽  
Secondary Ion Mass Spectrometry ◽  
Matrix Effects ◽  
Rutherford Backscattering Spectrometry ◽  
Relative Sensitivity ◽  
Epitaxial Films ◽  
Sensitivity Factor ◽  
Primary Composition ◽  
Secondary Ion

AbstractAluminum gallium nitride (AlGaN) material is used in GaN-based electronic and optoelectonic devices. The Al and Ga ratio can be adjusted to produce material with different compositions and electronic properties. In this set of experiments epitaxial films of (AlxGa1−x)0.5N0.5 with x ranging from 0 to 1 were investigated. Primary composition was determined with Rutherford backscattering spectrometry (RBS). From secondary ion mass spectrometry (SIMS) profiles a correlation of secondary ion counts was made to RBS determinations of primary composition. The SIMS data was also used to determine sputter rate and the relative sensitivity factor (RSF) of O, Mg and Si in (AlxGa1−x)0.5N0.5 material. The correlation of SIMS data with RBS and knowledge of the sputter rate and RSF dependence on composition are essential for the characterization of (AlxGa1−x)0.5N0.5 films

SIMS direct ion imaging in the mineralogical sciences

1996 ◽  
Vol 54 ◽  
pp. 698-699
Author(s):  
G. McMahon ◽  
L. J. Cabri
Keyword(s):  
Secondary Ion Mass Spectrometry ◽  
Matrix Effects ◽  
Matrix Material ◽  
High Sensitivity ◽  
Relative Sensitivity ◽  
Beam Current ◽  
Sensitivity Factor ◽  
Elemental Distribution ◽  
Sample Matrix ◽  
Secondary Ion

The use of secondary ion mass spectrometry (SIMS) has enjoyed increasing popularity in the mineralogical sciences owing to its high sensitivity to all elements in the periodic table with detection limits in the parts per million to parts per billion regime, coupled with the ability to display maps of elemental distribution at these detection levels with a spatial resolution of 1 μm. A description of the technique and its application to a wide variety of mineralogical problems has recently been reviewed.The drawback of SIMS is the rather complicated nature of quantification schemes necessitated by sample matrix effects, which refer to differences in the sensitivity for a given element in samples of different composition. These differences result from changes in the ionization efficiency and sputtering yield (sample matrix specific) as well as changes in secondary ion transmission and ion collection efficiencies (instrument specific). Therefore, the use of matrix-matched standards of known concentration is required to establish a calibration factor known as the relative sensitivity factor (RSF) which can be used to convert the experimentally measured secondary ion intensity into concentration values. Furthermore, the effect of changes in ion intensity caused by variations in primary beam current or analysis at different sample positions is removed by normalization to an ion species which represents the matrix material.

The Use of SIMS and SEM for the Characterization of Individual Particles with a Matrix Originating from a Nuclear Weapon

2007 ◽  
Vol 13 (3) ◽  
pp. 179-190 ◽  
Author(s):  
Ylva Ranebo ◽  
Mats Eriksson ◽  
Gabriele Tamborini ◽  
Nedialka Niagolova ◽  
Olivier Bildstein ◽  
...  
Keyword(s):  
Nuclear Weapons ◽  
Secondary Ion Mass Spectrometry ◽  
Isotopic Ratio ◽  
Relative Sensitivity ◽  
Mass Range ◽  
Morphological Properties ◽  
Sensitivity Factor ◽  
Surface Layers ◽  
X Ray

The application of scanning electron microscopy (SEM) and secondary ion mass spectrometry (SIMS) for characterization of mixed plutonium and uranium particles from nuclear weapons material is presented. The particles originated from the so-called Thule accident in Greenland in 1968. Morphological properties have been studied by SEM and two groups were identified: a “popcorn” structure and a spongy structure. The same technique, coupled with an energy-dispersive X-ray (EDX) spectrometer, showed a heterogeneous composition of Pu and U in the surface layers of the particles. The SIMS depth profiles revealed a varying isotopic composition indicating a heterogeneous mixture of Pu and U in the original nuclear weapons material itself. The depth distributions agree with synchrotron-radiation-based μ-XRF (X-ray fluorescence microprobe) measurements on the particle (Eriksson, M., Wegryzynek, D., Simon, R., & Chinea-Cano, E., in prep.) when a SIMS relative sensitivity factor for Pu to U of 6 is assumed. Different SIMS identified isotopic ratio groups are presented, and the influence of interferences in the Pu and U mass range are estimated. The study found that the materials are a mixture of highly enriched235U (235U:238U ratio from 0.96 to 1.4) and so-called weapons grade Pu (240Pu:239Pu ratio from 0.028 to 0.059) and confirms earlier work reported in the literature.

In-depth and ion image analysis of minor and trace constituents in V–Cr–Ti alloy welds

1996 ◽  
Vol 11 (8) ◽  
pp. 1923-1933 ◽  
Author(s):  
Robert W. Odom ◽  
Martin L. Grossbeck
Keyword(s):  
Trace Elements ◽  
Secondary Ion Mass Spectrometry ◽  
Tensile Elongation ◽  
Relative Sensitivity ◽  
Sensitivity Factor ◽  
Gas Tungsten Arc ◽  
Trace Constituents ◽  
Secondary Ion ◽  
Quantitative Sims ◽  
Alloy Metal

This paper describes the application of dynamic secondary ion mass spectrometry (SIMS) to the study of the chemistry of welds in V–Cr–Ti alloys and presents preliminary data on the distribution of minor and trace elements (H, C, N, O, P, S, and C1) in welds produced by gas tungsten arc (GTA) and electron beam techniques. The motivation for this research is to develop techniques that determine correlations between the concentration and distribution of trace elements in alloy metal welds and the physical properties of the weld. To this end, quantitative SIMS techniques were developed for N, O, and S analysis in vanadium alloy welds using an ion implantation/relative sensitivity factor methodology. The data presented in this paper demonstrate that trace compositions and distributions of selected welds correlate, at least qualitatively, with such properties as microhardness and tensile elongation. These data support continuing these investigations to develop microanalysis methods that quantitatively correlate weld composition with mechanical properties.

Manganese in 4H-SiC

2010 ◽  
Vol 645-648 ◽  
pp. 701-704
Author(s):  
Margareta K. Linnarsson ◽  
Aurégane Audren ◽  
Anders Hallén
Keyword(s):  
Mass Spectrometry ◽  
Heat Treatment ◽  
Ion Implantation ◽  
Depth Distribution ◽  
Secondary Ion Mass Spectrometry ◽  
Rutherford Backscattering Spectrometry ◽  
Rutherford Backscattering ◽  
P Type ◽  
Secondary Ion

Manganese diffusion in 4H-SiC for possible spintronic applications is investigated. Ion implantation is used to introduce manganese in n-type and p-type 4H-SiC and subsequent heat treatment is performed in the temperature range of 1400 to 1800 °C. The depth distribution of manganese is recorded by secondary ion mass spectrometry and Rutherford backscattering spectrometry in the channeling direction is employed for characterization of crystal disorder. After the heat treatment, the crystal order is improved and a substantial rearrangement of manganese is revealed in the implanted region. However, no pronounced manganese diffusion deeper into the sample is recorded.

Accurate Depth Profiling of Ultra-Thin Oxide Films by Secondary Ion Mass Spectrometry

1997 ◽  
Vol 477 ◽  
Author(s):  
Stephen P. Smith ◽  
Ming Hong Yang ◽  
Victor K. F. Chia
Keyword(s):  
Secondary Ion Mass Spectrometry ◽  
Matrix Effects ◽  
Depth Profiling ◽  
Relative Sensitivity ◽  
Sensitivity Factor ◽  
Large Area ◽  
Mos Capacitors ◽  
Thin Oxide Films ◽  
B Doping ◽  
Good Agreement

ABSTRACTSurfaceSIMS depth profile measurements of dopants in silicon wafers with thin thermal oxide layers are presented. Complete and accurate calibration of these profiles requires layered data reduction to adjust for residual matrix effects of a factor of two in the sputter rate and SIMS relative sensitivity factor in SiO2 compared with bulk silicon. Properly calibrated profiles show good agreement with expected ion implant profile shapes, and can reveal dopant pile-up at SiO2/Si interfaces (phosphorus, for example). Measured SurfaceSIMS profiles of B doping within the first 10 nm of the substrate Si of experimental large area MOS capacitors show good agreement with dopant profiles independently obtained from experimental C-V data.

Quantitative Secondary Ion Mass Spectrometry (SIMS) of III-V Materials

2001 ◽  
Vol 692 ◽  
Author(s):  
P. Van Lierde ◽  
C. Tian ◽  
B. Rothman ◽  
R. A. Hockett
Keyword(s):  
Mass Spectrometry ◽  
Secondary Ion Mass Spectrometry ◽  
Matrix Effects ◽  
Rutherford Backscattering Spectrometry ◽  
Accurate Determination ◽  
Molecular Ions ◽  
Minor Constituents ◽  
Detection Techniques ◽  
Ion Mass Spectrometry ◽  
Secondary Ion

AbstractSecondary ion mass spectrometry (SIMS) provides direct methods to characterize the chemical composition of III-V materials at major, minor and trace level concentrations as a function of layer depth. SIMS employs keV primary ions to sputter the surface and sensitive mass spectrometry techniques to mass analyze and detect sputtered secondary ions which are characteristic of the sample composition. In-depth compositional analysis of these materials by SIMS relies on a number of its unique features including: (1) keV primary ion sputtering yielding nanometer depth resolutions, (2) the use of MCs+ detection techniques for quantifying major and minor constituents, and (3) ion implant standards for quantifying trace constituents like dopants and impurities. Nanometer depth resolution in SIMS sputtering provides accurate detection of diffusion of dopants, impurities and major constituents. MCs+ refers to the detection of “molecular” ions of an element (M) and the Cs+ primary beam. MCs+ minimizes SIMS matrix effects in analysis for major and minor constituents, thus providing good quantification. This paper presents a SIMS study of AlxGa1−xAs structures with three different x values. MCs+ (M=Al or Ga) data are presented for the accurate determination of major and minor components. Rutherford backscattering spectrometry (RBS) and x-ray diffraction (XRD) data were crosscorrelated with the MCs+ results. Three specimens with different x values were ion implanted with H, C, O, Mg, Si, Zn and Se to study quantification of trace levels. SIMS data acquired on a double focusing instrument (CAMECA IMS-4f) and a quadrupole instrument (PHI ADEPT 1010) are also compared. Lastly, we discuss our efforts to improve the analysis precision for pand n-type dopants in AlGaAs which currently is ± 3% (1 sigma).

In-depth Analysis of the Impurities in GaN

1996 ◽  
Vol 1 ◽  
Author(s):  
A. P. Kovarsky ◽  
V. S. Strykanov
Keyword(s):  
Secondary Ion Mass Spectrometry ◽  
Dynamic Range ◽  
Detection Limits ◽  
Background Level ◽  
Epitaxial Films ◽  
Depth Analysis ◽  
Lower Detection ◽  
Minimum Detection Level ◽  
Ion Yields ◽  
Secondary Ion

GaN epitaxial films were analyzed by Secondary Ion Mass Spectrometry (SIMS). Standard implanted samples were used to determine the appropriate analytical conditions for analysis of impurities. The dose and energy of implantation for selected elements (Mg, Al, Si, Zn, Cd, H, C and O) were chosen so the maximum impurity concentration was not more than 1020 atoms/cm3. The optimum analysis conditions were ascertained from the standards for each element, and the detection limits were deduced from the background levels of the implantation profiles. We demonstate that lower detection limits of 1015 atoms/cm3 with a dynamic range 103 − 105 are possible. Zn and Cd have low ion yields, so the minimum detection level for these elements is the background level of the detector. The detection limits of the other elements are determined by the contamination of an initial GaN matrix.

Calibration Method for Elemental Quantification

2000 ◽  
Vol 6 (S2) ◽  
pp. 536-537
Author(s):  
C. B. Vartuli ◽  
F. A. Stevie ◽  
L. A. Giannuzzi ◽  
T. L. Shofner ◽  
B. M. Purcell ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Peak Concentration ◽  
Energy Dispersive Spectrometry ◽  
Secondary Ion Mass Spectrometry ◽  
Rutherford Backscattering Spectrometry ◽  
Calibration Method ◽  
High Dose ◽  
High Concentration ◽  
Borophosphosilicate Glass ◽  
Secondary Ion

Energy Dispersive Spectrometry (EDS) is generally calibrated for quantification using elemental standards. This can introduce errors when quantifying non-elemental samples and does not provide an accurate detection limit. In addition, variations between analysis tools can lead to values that differ considerably, especially for trace elements. By creating a standard with an exact trace composition, many of the errors inherent in EDS quantification measurements can be eliminated.The standards are created by high dose ion implantation. For ions implanted into silicon, a dose of 1E16 cm-2 results in a peak concentration of approximately 1E21 cm-3 or 2% atomic. The exact concentration can be determined using other methods, such as Rutherford Backscattering Spectrometry (RBS) or Secondary Ion Mass Spectrometry (SIMS). For this study, SIMS analyses were made using a CAMECA IMS-6f magnetic sector. Measurement protocols were used that were developed for high concentration measurements, such as B and P in borophosphosilicate glass (BPSG).

Sign in / Sign up

Export Citation Format

Share Document