A simple erosion dynamics model of molecular sputter depth profiling

A simple model which describes the essential features commonly observed in a molecular sputter depth profile is presented. General predictions of the dependence of measured molecular ion signals on the primary ion fluence are derived for the specific case where a mass spectrometric technique such as SIMS or secondary neutral mass spectrometry (SNMS) is used to analyze the momentary surface. The results are compared with recent experimental data on molecular depth profiles obtained by cluster‐ion‐initiated SIMS of organic overlayers. Copyright © 2008 John Wiley & Sons, Ltd.     

Image processing in secondary ion mass spectrometry

The application of image processing in secondary ion mass spectrometry is discussed. The Cameca 4f SIMS uses a single microchannel plate and a highly sensitive camera in combination with an image processor with real time capabilities (Kontron IBAS). An automation procedure with image integration, extended dynamic range image acquisition and retro depth profiling is presented and illustrated with practical applications.     

Quantitative Depth Profiling of K-Doped Fullerene Films Using XPS and SIMS

 Phenomena accompanying electrochemical doping of solid fullerene films with potassium were studied by sputter ion depth profiling (XPS and SIMS). The potassium distribution was determined, and artifacts associated with possible damage of the layer composition caused by ion impact were investigated and discussed. To compare the charge transfer while reductive doping is taking place at fullerene/solution interface with doping from gas phase, model layers were prepared and doped by potassium under UHV conditions. It was found that sputtering by Ar⁺ primary ions yields both accurate information on the alkaline metal distribution and on its concentration. Sputtering by O⁺ ions led to an enrichment of potassium, apparently due to the reactivity of oxygen with the fullerene matrix. It is shown that the reductive doping starts at the fullerene/solution interface. The concentration of potassium in the doped films was found to be lower than expected from the charge transferred during the electrochemical reduction. Other phase transformations such as hydrogenation are discussed. Received March 4, 2002; accepted July 26, 2002     

Evaluation of the sputtering rate variation in SIMS ultra‐shallow depth profiling using multiple short‐period delta layers

We have developed multiple short‐period delta layers as a reference material for SIMS ultra‐shallow depth profiling. Boron nitride delta layers and silicon spacer layers were sputter‐deposited alternately, with a silicon spacer thickness of 1–5 nm. These delta‐doped layers were used to measure the sputtering rate change in the initial stage of oxygen ion bombardment. A significant variation of sputtering rate was observed in the initial 3 nm or less. The sputtering rate in the initial 3 nm was estimated to be about four times larger than the steady‐state value for 1000 eV oxygen ions. Copyright © 2003 John Wiley & Sons, Ltd.     

Summary of ISO/TC 201 Standard: X ISO 17560:2002—Surface chemical analysis—Secondary ion mass spectrometry—Method for depth profiling of boron in silicon

This International Standard 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 calibration. This method is applicable to single‐crystal, polycrystal or amorphous silicon specimens with boron atomic concentrations between 1 × 10¹⁶ and 1 × 10²⁰ atoms cm^?3, and to the crater depth of 50 nm or deeper. Optical interferometry is generally applicable to crater depths in the range 0.5–5 µm. Copyright © 2004 John Wiley & Sons, Ltd.