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.

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.

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 Depth Profiling Free of Martix Effects

2005 ◽  
Vol 908 ◽  
Author(s):  
Peter Huber ◽  
Helmut Karl ◽  
Bernd Stritzker
Keyword(s):  
Elemental Concentration ◽  
Secondary Ion Mass Spectrometry ◽  
Matrix Effects ◽  
Depth Profiling ◽  
High Dose ◽  
Concentration Depth Profile ◽  
The Matrix ◽  
Elemental Depth ◽  
Secondary Ion ◽  
Sims Depth Profiling

AbstractWe present a method of determining elemental depth profiles with secondary ion mass spectrometry (SIMS) corrected by all non-linearities between the SIMS countrate and the elemental concentration caused by chemical matrix effects, resulting in an absolute concentration depth profile. The key to this method is a low dose ion implantation step of corresponding reference isotopes prior to SIMS depth profiling. Spectra evaluation is performed on the basis of a selfconsistent evaluation in which the depth dependent influence of the matrix is determined. The technique is demonstrated for sequentially high dose ion implanted Cd and Se in SiO2.

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.

Nuclear Reaction Analysis of Shallow B And Bf2 Implants in Si

1987 ◽  
Vol 92 ◽  
Author(s):  
Mark C. Ridgway ◽  
P J. Scanlon ◽  
J.L. Whitton
Keyword(s):  
Nuclear Reaction ◽  
Secondary Ion Mass Spectrometry ◽  
Matrix Effects ◽  
Depth Profiling ◽  
Impurity Diffusion ◽  
System Model ◽  
Nuclear Reaction Analysis ◽  
Near Surface ◽  
Annealing Conditions ◽  
Secondary Ion

ABSTRACTImpurity diffusion induced by rapid thermal annealing (RTA) has been investigated for low energy B and BF2 implants in crystalline and preamorphized Si. A 50 keV 2×1015/cm2 Si self-implant was used for preamorphization. Samples were annealed with an oxide cap in an AG Associates HEATPULSE system (model 210T). Prior to the impurity depth profiling measurements, the SiO2 was removed with dilute HF. Significant B diffusion to theSiO2/Si interface was observed for a 1050°C/10 s anneal of 10 keV 3×1015/cm2 implanted;11B in crystalline and preamorphized Si. B interfacial concentrations were comparableto peak concentrations in unannealed samples. Diffusion of B and F to the SiO2/Si interface, and impurity gettering by ion straggling damage were observed for a 1050°C/10 s anneal of 45 keY 3×1O15/cm2 implanted 49BF2 in crystalline Si.though a loss F was apparent.Depth profiles were determined with nuclear reaction analysis (NRA) [1-3], specifically the 11B(ρ,α0)8 Be(ER=163 key) [4] and 19F(ραγ)160 (ER - 340 keV) [5] reactions for 1lB and 19F profiling, respectively. This technique is sensitive to impurities at or near the surface and can reveal impurity diffusion to near-surface regions not usually detectable with secondary ion mass spectrometry (SIMS). NRA depth profiling has shownthat RTA can result in significant impurity diffusion to the SiO2/Si interface for B implanted in crystalline and preamorphized Si, and BF2 implanted in crystalline Si. Impurity concentrations at the interface are estimated to be in excess of 1020/cm3 for the implantation and annealing conditions used in this report. BF2 implanted in preamorphized Si showed greatly reduced impurity concentrations at the interface. A knowledge of the impurity concentrations at the substratesurface or the SiO2/Si interface becomes increasingly important as device dimensions decrease. Matrix effects make such measurements difficult with SIMS.

Atomic force microscopy (AFM) of the topography of silicon surfaces exposed to ion beams

1992 ◽  
Vol 50 (2) ◽  
pp. 1132-1133
Author(s):  
Mark Denker ◽  
Jennifer Wall ◽  
Mark Ray ◽  
Richard Linton
Keyword(s):  
Secondary Ion Mass Spectrometry ◽  
Incidence Angle ◽  
Ion Beam ◽  
Depth Profiling ◽  
Depth Resolution ◽  
Ion Beams ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Trace Impurities ◽  
Energy Dose

Reactive ion beams such as O2+ and Cs+ are used in Secondary Ion Mass Spectrometry (SIMS) to analyze solids for trace impurities. Primary beam properties such as energy, dose, and incidence angle can be systematically varied to optimize depth resolution versus sensitivity tradeoffs for a given SIMS depth profiling application. However, it is generally observed that the sputtering process causes surface roughening, typically represented by nanometer-sized features such as cones, pits, pyramids, and ripples. A roughened surface will degrade the depth resolution of the SIMS data. The purpose of this study is to examine the relationship of the roughness of the surface to the primary ion beam energy, dose, and incidence angle. AFM offers the ability to quantitatively probe this surface roughness. For the initial investigations, the sample chosen was <100> silicon, and the ion beam was O2+.Work to date by other researchers typically employed Scanning Tunneling Microscopy (STM) to probe the surface topography.

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