Many of today’s products engineered in the automotive, aerospace, marine, construction andsemiconductor industry depend upon the precise control of microstructural and compositional properties on the surface or subsurface to achieve unique properties including corrosion resistance, performance enhancement, and extended lifetime. A few examples of the applications or products that benefit from the GD-OES instrumentation available at EMSL Analytical are: hard disks, PZT layers, deposition layers to achieve optical properties, case hardening and thin oxides on alloys, and many more.
The GD-OES system at EMSL utilizes pulse matched RF source, the only technique that can provide both surface, depth profile and bulk elemental composition with high sensitivity for all elements (including the light elements) applicable to almost all solid materials, including metals, metal alloy coatings, semiconductors, polymer coatings, and glass.
Subsection of specific test results or designed targets:
- Bulk elemental composition (no Click)
- Surface Science/Thin Films
Surface Science/Thin films click-on:
Depth profile analysis is a continuous process of sputtering through a sample at a rate of typically 3 microns per minute. The results are usually presented as concentration of elements versus depth; hence the analysis offers both the elemental composition and the thickness of subsequent layers. The GD-OES profiler at EMSL Analytical provides the ability to measure elements at both trace and major concentrations instantaneously. The low energy of the incident particles of the instrument assures minimal surface damage and the speed of sputtering and signal collection allow depth profiles of both thin and thick films such as PVD/CVD thin films, semiconductors, coated steels, metals alloys, ceramics, and layers on glass.
Products & Applications List:
Useful applications for GD-OES include Lithium Battery depth profiling of positive and negative electrodes, chemical composition measurements, etc.
Figure 1. Example of GD-OES depth profiling of a coated metal sample (At% vs depth).
XPS – X-ray Photoelectron Spectroscopy
X-ray Photoelectron Spectroscopy is a valuable tool for surface science and chemical analysis of a wide variety of materials. XPS allows for a wide variety of elements to not only be identified and quantified, but for chemical state information regarding these elements in the sample to be determined. XPS bombards a vacuum stable sample with a concentrated beam of x-rays, allowing the interaction of the x-ray beam and the sample to liberate electrons from the sample. By correlating the energy of liberated electrons with known binding energies, the spectrum of electron energies gives quantitative and oxidation state information about the elements on the sample surface.
Because of the detailed oxidation state information XPS allows for very detailed information about the relative chemical environment in a sample. Because the electrons liberated from the sample need to migrate to the detector, this chemical information is only obtained from a very small volume of material at the surface of a sample. This allows for analysis that is very surface specific, leading to nm scale interaction with the surface, with a thin film sample orientation profile of 2nm easily achievable. Due to the extreme surface sensitivity, small amounts of contaminants can often interfere with the desired material, and so the instrument is equipped with an ion sputter gun for surface cleaning. With the proper alignment, samples can also be successively sputtered to perform analysis at varying depth, creating a depth resolved profile of composition. Analysis of depth profile, surface film analysis, work-function measurements, and surface mapping by composition are all possible with this technique.
XPS is a preferred technique for thin film electronics. Examination of thin contaminants or surface poisoning is possible using the extreme sensitivity of the instrument, allowing for fine auto-oxidation layers or staining to be identified. Semi-conductors, organo-metallic polymers, composite materials, and all manner of metals and ceramic materials can be examined using XPS to both guide process and materials research, as well as determine root cause of material contamination or disruption.