ISO/TC 201/SC 6 - Secondary ion mass spectrometry

This document specifies a method for determining the maximum count rate for an acceptable limit of divergence from linearity of the intensity scale in single ion counting time-of-flight (TOF) secondary ion mass spectrometers using a test based on isotopic ratios in spectra from poly(tetrafluoroethylene) (PTFE). It also includes a method to correct for intensity nonlinearity arising from intensity lost from a microchannel plate (MCP) or scintillator and photomultiplier followed by a time-to-digital converter (TDC) detection system caused by secondary ions arriving during its dead-time. The correction can increase the intensity range for 95 % linearity by a factor of up to more than 50 so that a higher maximum count rate can be employed for those spectrometers for which the relevant correction formulae have been shown to be valid.

This document specifies a method for measuring the mass resolution in SIMS, and how to compare the mass resolution between different instruments (e.g. TOF-SIMS, Magnetic SIMS, Quadrupole SIMS, Fourier Transform SIMS, etc.) by considering the peak shapes.

This document specifies a method of determining relative sensitivity factors (RSFs) for secondary-ion mass spectrometry (SIMS) from ion-implanted reference materials. The method is applicable to specimens in which the matrix is of uniform chemical composition, and in which the peak concentration of the implanted species does not exceed one atomic percent.

This document specifies a method for measuring and reporting argon cluster sputtering yield volumes of a specific organic material. The method requires one or more test samples of the specified material as a thin, uniform film of known thickness between 50 and 1 000 nanometres on a flat substrate which has a different chemical composition to the specified material. This document is applicable to test samples in which the specified material layer has homogeneous composition in depth and is not applicable if the depth distribution of compounds in the specified material is inhomogeneous. This document is applicable to instruments in which the sputtering ion beam irradiates the sample using a raster to ensure a constant ion dose over the analysis area.

This document specifies a method to optimize the mass calibration accuracy in time-of-flight secondary ion mass spectrometry (SIMS) instruments used for general analytical purposes. It is only applicable to time-of-flight instruments but is not restricted to any particular instrument design. Guidance is provided for some of the instrumental parameters that can be optimized using this procedure and the types of generic peaks suitable to calibrate the mass scale for optimum mass accuracy.

ISO 20411:2018 specifies a method for determining the maximum count rate for an acceptable limit of divergence from linearity of the intensity scale in pulse counting magnetic sector-type secondary ion mass spectrometers or quadrupole secondary ion mass spectrometers. It uses a test based on depth profile analysis of two isotopes in a reference material which has a gradual concentration change between low and high concentration regimes. It also includes a correction method for saturated intensity caused by the dead time of the detector. The correction can increase the intensity range for 95 % linearity so that a higher maximum count rate can be employed for those spectrometers for which the relevant correction equations have been shown to be valid. ISO 20411:2018 does not apply to time of flight mass spectrometers. ISO 20411:2018 is only applicable to elements with minor isotopes. It is not applicable if the element is monoisotopic or contains isotopes with equal abundances.

ISO 17560:2014 specifies a secondary-ion mass spectrometric method using magnetic-sector or quadrupole mass spectrometers for depth profiling of boron in silicon, and using stylus profilometry or optical interferometry for depth scale calibration. This method is applicable to single-crystal, poly-crystal, or amorphous silicon specimens with boron atomic concentrations between 1 × 1016 atoms/cm3 and 1 × 1020 atoms/cm3, and to crater depths of 50 nm or deeper.

ISO 12406:2010 specifies a secondary-ion mass spectrometric method using magnetic-sector or quadrupole mass spectrometers for depth profiling of arsenic in silicon, and using stylus profilometry or optical interferometry for depth calibration. This method is applicable to single-crystal, poly-crystal or amorphous silicon specimens with arsenic atomic concentrations between 1 x 1016 atoms/cm3 and 2,5 x 1021 atoms/cm3, and to crater depths of 50 nm or deeper.

ISO 14237:2010 specifies a secondary-ion mass spectrometric method for the determination of boron atomic concentration in single-crystalline silicon using uniformly doped materials calibrated by a certified reference material implanted with boron. This method is applicable to uniformly doped boron in the concentration range from 1 x 1016 atoms/cm3 to 1 x 1020 atoms/cm3.

ISO 23812:2009 specifies a procedure for calibrating the depth scale in a shallow region, less than 50 nm deep, in SIMS depth profiling of silicon, using multiple delta-layer reference materials. It is not applicable to the surface-transient region where the sputtering rate is not in the steady state. It is applicable to single-crystalline silicon, polycrystalline silicon and amorphous silicon.

ISO 23830:2008 specifies a method for confirming the repeatability and constancy of the positive-ion relative-intensity scale of static secondary-ion mass spectrometers, for general analytical purposes. It is only applicable to instruments that incorporate an electron gun for charge neutralization. It is not intended to be a calibration of the intensity/mass response function. That calibration may be made by the instrument manufacturer or another organization. The present method provides data to confirm the constancy of relative intensities with instrument usage. Guidance is given on some of the instrument settings that may affect this constancy.

ISO 20341:2003 specifies procedures for estimating three depth resolution parameters, viz the leading-edge decay length, the trailing-edge decay length and the Gaussian broadening, in SIMS depth profiling using multiple delta-layer reference materials. It is not applicable to delta-layers where the chemical and physical state of the near-surface region, modified by the incident primary ions, is not in the steady state.

ISO 17862:2014 specifies a method for determining the maximum count rate for an acceptable limit of divergence from linearity of the intensity scale in single ion counting time-of-flight (TOF) secondary ion mass spectrometers using a test based on isotopic ratios in spectra from poly(tetrafluoroethylene) (PTFE). It also includes a method to correct for intensity nonlinearity arising from intensity lost from a microchannel plate (MCP) or scintillator and photomultiplier followed by a time-to-digital converter (TDC) detection system caused by secondary ions arriving during its dead-time. The correction can increase the intensity range for 95 % linearity by a factor of up to more than 50 so that a higher maximum count rate can be employed for those spectrometers for which the relevant correction formulae have been shown to be valid. ISO 17862:2014 can also be used to confirm the validity of instruments in which the dead-time correction is already made but in which further increases can or cannot be possible.

ISO 13084:2011 specifies a method to optimize the mass calibration accuracy in time-of-flight SIMS instruments used for general analytical purposes. It is only applicable to time-of-flight instruments but is not restricted to any particular instrument design. Guidance is provided for some of the instrumental parameters that can be optimized using this procedure and the types of generic peaks suitable to calibrate the mass scale for optimum mass accuracy.

ISO 18114:2003 specifies a method of determining relative sensitivity factors (RSFs) for secondary-ion mass spectrometry (SIMS) from ion-implanted reference materials. The method is applicable to specimens in which the matrix is of uniform chemical composition, and in which the peak concentration of the implanted species does not exceed one atomic percent.

ISO 17560:2002 specifies a secondary-ion mass spectrometric method using magnetic-sector or quadrupole mass spectrometers for depth profiling of boron in silicon, and using stylus profilometry or optical interferometry for depth scale calibration. This method is applicable to single-crystal, poly-crystal or amorphous-silicon specimens with boron atomic concentrations between 1×1016 atoms/cm3 and 1×1020 atoms/cm3, and to crater depths of 50 nm or deeper.