SIMS：Secondary Ion Mass Spectrometry
Features
When accelerated ions irradiate the sample surface, various particles such as electrons, atoms, small molecules, and ions are emitted from the sample surface.
SIMS is a method for qualitative and quantitative analysis of the constituents in a sample by measuring the mass and amount of emitted ions. The features include:
- High sensitivity (ppb to ppm)
- Wide range of elements (H to U).
- Concentrations ranging from that of the principal constituent to trace impurities
- Quantitative analysis using standard samples
- Depth direction analysis
- Nanometer depth resolution
- Wide area range of region of interest
- Isotope analysis
Application Examples
- Depth distribution of ion-implanted elements
- Quantitative and qualitative contamination analysis of laminated film interfaces
- Distribution and concentration of impurities in the films
- Compositional analysis of III-V multiple quantum-well compound semiconductors
- Two- and three-dimensional distribution of impurity elements in semiconductors
- Identification of various metallic, inorganic, organic materials, and carbon compounds
Principle
Primary ions such as O2- and Cs- are accelerated and impinge on the surface of the sample. As a result, atoms near the surface are ionized and escape into vacuum as secondary ions (sputtering). Mass spectrometry is used to analyse the secondary ions, thereby enabling a qualitative and quantitative analysis of the constituents of the sample (see Fig. 2).
Data examples
The concentration of secondary ions is expressed as atoms per cm3, whereas the secondary ion intensity is expressed as the number of secondary ions detected per second (see Fig. 3 and Fig. 4).
Visualization of impurity concentration distribution in any plane or cross section is possible (Fig. 5).
Data delivery format
Profile data : Portable Document Format (PDF) file and MST Profile Viewer format (.PRW)*
Numerical data : Microsoft® Excel files
* MST Profile Viewer format (.PRW) is MST proprietary file format, which can be viewed and processed by "Profile Viewer software" distributed by MST.
Specifications
Items for enquiries
- Purpose and content of measurement
- Sample information
- Number of samples, and availability of preliminary samples
- Structure, shape, lamination, thickness of each layer, presence or absence of patterns and surrounding insulators, ion implantation conditions
- Handling instructions
- Details on delivery
- Preferred due date for preliminary analysis report
- Due date for delivery of final report
- Priority in the case of a large number of samples
- Any other issues
Caution
Samples with the following properties may adversely affect the analysis results:
- Large surface roughness
- Semiconductor device chips
- Pattered structures
- Large outgassing that affects the vacuum level
［SIMS］二次イオン質量分析法の分析事例はこちらからご覧ください。