skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Secondary ion mass spectrometry depth profiling of amorphous polymer multilayers using O{sub 2}{sup +} and Cs{sup +} ion bombardment with a magnetic sector instrument

Abstract

Thin planar polymer films are model systems in a number of fields, including nano- and biotechnology. In contrast to reciprocal space techniques such as reflectivity or diffraction, secondary ion mass spectrometry (SIMS) can provide depth profiles of tracer labeled polymers in real space directly with sufficient depth resolution to characterize many important aspects in these systems. Yet, continued improvements in characterization methods are highly desirable in order to optimize the trade-offs between depth resolution, mass resolution, detection sensitivity, data acquisition time, and artifacts. In this context, the utility of a magnetic sector SIMS instrument for amorphous polymer film analysis was evaluated using model polymer bilayer systems of polystyrene (PS) with poly(methyl methacrylate) (PMMA), PS with poly(2-vinylpyridine), and poly(cyclohexyl methacrylate) (PCHMA) with PMMA. Deuterium-labeled polystyrene embedded in PS or PCHMA at concentrations ranging from 5% to 20%(v/v) was used as tracer polymer. Analysis conditions for a magnetic sector SIMS instrument (CAMECA IMS-6f) were varied to achieve a depth resolution of {approx}10 nm, high signal/noise ratios, and high sensitivity, while minimizing matrix effects and sample charging. Use of Cs{sup +} and O{sub 2}{sup +} primary ions with detection of negative and positive secondary ions, respectively, has been explored. Primary beam impact energymore » and primary ion species have been shown to affect matrix secondary ion yields. Sputtering rates have been determined for PS and PMMA using both primary ion species and referenced to values for intrinsic (100) silicon (Si) under identical analysis conditions.« less

Authors:
; ;  [1];  [2];  [2]
  1. Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States)
  2. (United States)
Publication Date:
OSTI Identifier:
20777054
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films; Journal Volume: 24; Journal Issue: 2; Other Information: DOI: 10.1116/1.2172948; (c) 2006 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; AMORPHOUS STATE; CESIUM IONS; DEPTH; DETECTION; DEUTERIUM; FILMS; INTERNATIONAL MAGNETOSPHERIC STUDY; ION BEAMS; ION MICROPROBE ANALYSIS; MASS RESOLUTION; MASS SPECTROSCOPY; METHACRYLATES; METHACRYLIC ACID ESTERS; PMMA; POLYSTYRENE; REFLECTIVITY; SENSITIVITY; SILICON; SPUTTERING

Citation Formats

Harton, S.E., Stevie, F.A., Ade, H., Analytical Instrumentation Facility, North Carolina State University, Raleigh, North Carolina 27695, and Department of Physics, North Carolina State University, Raleigh, North Carolina 27695. Secondary ion mass spectrometry depth profiling of amorphous polymer multilayers using O{sub 2}{sup +} and Cs{sup +} ion bombardment with a magnetic sector instrument. United States: N. p., 2006. Web. doi:10.1116/1.2172948.
Harton, S.E., Stevie, F.A., Ade, H., Analytical Instrumentation Facility, North Carolina State University, Raleigh, North Carolina 27695, & Department of Physics, North Carolina State University, Raleigh, North Carolina 27695. Secondary ion mass spectrometry depth profiling of amorphous polymer multilayers using O{sub 2}{sup +} and Cs{sup +} ion bombardment with a magnetic sector instrument. United States. doi:10.1116/1.2172948.
Harton, S.E., Stevie, F.A., Ade, H., Analytical Instrumentation Facility, North Carolina State University, Raleigh, North Carolina 27695, and Department of Physics, North Carolina State University, Raleigh, North Carolina 27695. Wed . "Secondary ion mass spectrometry depth profiling of amorphous polymer multilayers using O{sub 2}{sup +} and Cs{sup +} ion bombardment with a magnetic sector instrument". United States. doi:10.1116/1.2172948.
@article{osti_20777054,
title = {Secondary ion mass spectrometry depth profiling of amorphous polymer multilayers using O{sub 2}{sup +} and Cs{sup +} ion bombardment with a magnetic sector instrument},
author = {Harton, S.E. and Stevie, F.A. and Ade, H. and Analytical Instrumentation Facility, North Carolina State University, Raleigh, North Carolina 27695 and Department of Physics, North Carolina State University, Raleigh, North Carolina 27695},
abstractNote = {Thin planar polymer films are model systems in a number of fields, including nano- and biotechnology. In contrast to reciprocal space techniques such as reflectivity or diffraction, secondary ion mass spectrometry (SIMS) can provide depth profiles of tracer labeled polymers in real space directly with sufficient depth resolution to characterize many important aspects in these systems. Yet, continued improvements in characterization methods are highly desirable in order to optimize the trade-offs between depth resolution, mass resolution, detection sensitivity, data acquisition time, and artifacts. In this context, the utility of a magnetic sector SIMS instrument for amorphous polymer film analysis was evaluated using model polymer bilayer systems of polystyrene (PS) with poly(methyl methacrylate) (PMMA), PS with poly(2-vinylpyridine), and poly(cyclohexyl methacrylate) (PCHMA) with PMMA. Deuterium-labeled polystyrene embedded in PS or PCHMA at concentrations ranging from 5% to 20%(v/v) was used as tracer polymer. Analysis conditions for a magnetic sector SIMS instrument (CAMECA IMS-6f) were varied to achieve a depth resolution of {approx}10 nm, high signal/noise ratios, and high sensitivity, while minimizing matrix effects and sample charging. Use of Cs{sup +} and O{sub 2}{sup +} primary ions with detection of negative and positive secondary ions, respectively, has been explored. Primary beam impact energy and primary ion species have been shown to affect matrix secondary ion yields. Sputtering rates have been determined for PS and PMMA using both primary ion species and referenced to values for intrinsic (100) silicon (Si) under identical analysis conditions.},
doi = {10.1116/1.2172948},
journal = {Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films},
number = 2,
volume = 24,
place = {United States},
year = {Wed Mar 15 00:00:00 EST 2006},
month = {Wed Mar 15 00:00:00 EST 2006}
}
  • The authors have used a CF/sub 3//sup +/ primary ion source for some typical depth profiling applications in secondary ion mass spectrometry and compared its performance with the conventionally used O/sub 2//sup +/ source. At the same accelerating potential, steady-state secondary ion emission conditions are reached much faster under CF/sub 3//sup +/ than under O/sub 2//sup +/ bombardment. Shallow implant profiles can be measured with better definition. This improvement is directly related to the shorter converted layer range produced at 5 keV CF/sub 3//sup +/ versus 5 keV O/sub 2//sup +/. The better depth solution found under CF/sub 3//sup +/more » bombardment may also be rationalized by the same reason of a shorter intermixed range at the interface. However, this is shown at least in part to be due to a smoother surface generated compared to the surface after O/sub 2//sup +/ bombardment.« less
  • In this paper we have described the use of secondary-ion mass spectrometry (SIMS), solid state {sup 29}Si magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) and transmission electron microscopy (TEM) to detect the existence of amorphous silica in Ti{sub 3}SiC{sub 2} oxidised at 500-1000 C. The formation of amorphous SiO{sub 2} and growth of crystalline TiO{sub 2} with temperature was monitored using dynamic SIMS and synchrotron radiation diffraction. A duplex structure with an outer TiO{sub 2}-rich layer and an inner mixed layer of SiO{sub 2} and TiO{sub 2} was observed. Results of NMR and TEM verified for the first time the directmore » evidence of amorphous silica formation during the oxidation of Ti{sub 3}SiC{sub 2} at the temperature range 500-1000 C.« less
  • This article presents a comparison of Cameca IMS 4f secondary ion-mass spectrometry (SIMS) measurements and resonant postionization mass spectrometry (RIMS) measurements of boron depth profiles in silicide/silicon samples (mainly CoSi{sub 2}/Si). The emphasis of the comparison was on the shape of the profiles obtained with both techniques. For the SIMS data, we used a quantification procedure including a correction for sensitivity differences in both matrices. The RIMS sensitivity in CoSi{sub 2}, TiSi{sub 2}, and Si was explicitly compared using special test samples and shown to be identical to within 15{percent}. Finally, we present preliminary results of the application of SIMSmore » and RIMS to a number of CoSi{sub 2}/Si samples with an unknown B profile. After application of the correction procedures, both techniques appear to produce nearly identical profile shapes in case of polycrystalline CoSi{sub 2} samples. For epitaxially grown crystalline CoSi{sub 2}, however, differences sometimes remain, depending on the temperature of the second silicidation anneal used. Absolute quantification of the RIMS profiles could be achieved through the use of an internal implantation standard. {copyright} {ital 1996 American Vacuum Society}« less
  • Changes in secondary ion yields of matrix and dopant species have been correlated with changes in surface topography during O/sup +//sub 2/ bombardment of Si and GaAs. In Si, profiles were measured in (100) wafers at 6- and 8-keV impact energy. At 6 keV, a yield increase of about 70% occurred for Si/sup +/ over a depth range of 2.5 to 3.5 ..mu..m, with changes in other species ranging from a decrease of approx.20% for Si/sup +//sub 3/ to an increase of more than 25% for O/sup +/. The development of a rippled surface topography was observed in scanning electronmore » micrographs over the same depth range. Similar effects occurred over a 3--5 ..mu..m depth range for 8-keV ions, and in (111) silicon at a depth of 3 to 4 ..mu..m for 6-keV ions. No differences were noted between p- and n-type silicon, or implanted and unimplanted silicon. In GaAs, profiles were measured in (100) wafers at 2.5-, 5.5-, and 8-keV impact energies. At 8 keV, a yield increase of about 70% was found for GaO/sup +/ in the range 0.6--1.0 ..mu..m, with smaller changes for other matrix species. At 5.5 keV, similar effects were observed, but over a depth interval of 0.3 to 0.7 ..mu..m. No yield changes were detected at 2.5-keV impact energy. The yield changes at the higher energies were again correlated with the onset of changes in topography. No change in ion yield or surface topography was noted for Cs/sup +/ bombardment of Si or GaAs. The topography and ion yield changes are affected by the angle of incidence and, for Si, the oxygen coverage. The results show that the practice of normalizing secondary ion mass spectrometry dopant profiles to a matrix signal must be modified for situations where matrix yield changes occur.« less