Real World Applications of XPS
OVERVIEW: XPS or ESCA Surface Analyses
- Measures all elements except hydrogen and helium to a depth of about 20 nm
- Argon ion etching allows composition analysis to greater depths
- Analysis of the composition of ceramic precursor powders or particles
- Analysis of surface contamination of fired ceramics
- Check chemistry of binding agents to promote sintering
- Measure water content, impurities, and reacted layers on raw ceramic material particles
- Analysis of fracture surface chemistry to determine binder and pre-sintered particle surface chemistry effects on fracture plane
- Degradation effects upon ceramic such as caused by moisture on boron nitride (BN) or on alumina (Al2O3)
- Precise quantitative chemical phase identifications
- Measure changes in ceramic due to environment, such as leaching of elements, chemical uptake in the voids between poorly sintered particles, and reaction products
- Detect interparticle chemistries that may change insulation or RF response properties of the ceramic
Ceramic Analysis by XPS or ESCA Surface Analysis:
- Measures all elements except hydrogen and helium to a depth of about 20 nm
- Argon ion etching allows composition analysis to greater depths
- Analysis of the composition of ceramic precursor powders or particles
- Analysis of surface contamination of fired ceramics
- Check chemistry of binding agents to promote sintering
- Measure water content, impurities, and reacted layers on raw ceramic material particles
- Analysis of fracture surface chemistry to determine binder and pre-sintered particle surface chemistry effects on fracture plane
- Degradation effects upon ceramic such as caused by moisture on boron nitride (BN) or on alumina (Al2O3)
- Precise quantitative chemical phase identifications
- Measure changes in ceramic due to environment, such as leaching of elements, chemical uptake in the voids between poorly sintered particles, and reaction products
- Detect interparticle chemistries that may change insulation or RF response properties of the ceramic
Glass Analysis by XPS or ESCA Surface Analysis
- Quantitative elemental composition of a surface for all elements except hydrogen as-received or freshly fractured
- Surface chemistry after chemical exposure to treat surface for bonding or other surface treatment
- Silane coupling agent coverage on surface for adhesive bonding
- Anti-reflective coating analysis by depth profiling of elements
- Study leaching of glass which may leach Na, Ca, K, or B among other elements
- Measure profile of chemically-hardened glass such as potassium substitution for sodium
- Identify cause of etch-attack of glass
- Measure surface contamination
- Evaluate glass microspheres, frits, and fibers for adhesive bonding by examining for alkali surface chemistry
- Distinguish E and S fiberglass
- Characterize the chemistry of silicates and silica gels, which can be complex
- Analyze cause of failure of adhesive bonding
Composite Analysis by XPS or ESCA Surface Analysis:
- Polymer matrix composition with quantitative elemental and functional group chemical analysis
- Contamination on surface affecting adhesive bonding such as from mold release agents or short chain length airborne silicones
- Surface chemistry of fiberglass and fill particle materials affecting bonding or water release properties
- Identification and thickness measurement of silane coupling agents on additive surfaces
- Residue measurements and detection on extruded fibers of such compounds as calcium or zinc stearate
- Detection of sizing or sizing residues on fibers
- Identification of solid residue due to fill materials after TGA burn-off of polymer matrix
- Identification of E or S fiberglass after TGA burn-off of polymer matrix
- Surface chemistry of fibers, whiskers, or particles due to surface treatments such as cleaning, abrasion, plasma treating, environmental exposure, or degradation
- Interphase chemistry at interfaces where local compositions vary over 10 nm and even 1 micrometer scales in various cases compared to the bulk chemistry further away from the interface
Metal Analysis by XPS or ESCA Surface Analysis:
- Surface contamination detection and identification
- Surface oxide chemistry
- Identification of corrosion products
- Measure Cr to Fe ratio in stainless steel surface oxides to check passivation effectiveness in the base metal, at a weld, and in the Heat Affected Zone (HAZ).
- Surface segregation of elements in alloys; carbon, sulfur, and phosphorus being examples in addition to metal elements
- Depth profile elemental analysis to measure graphitic carbon and carbide concentrations as a function of depth
- Determine the chemistry of anodized surfaces
- Determine cause of adhesive bond failures on metal surfaces
- Examine the surface chemistry of metal particles prior to sintering for powdered metallurgy
Mineral Inorganic Analysis by XPS or ESCA Surface Analysis:
- Quantitative elemental analysis for all elements except hydrogen and helium to a depth of about 20 nm
- Particle surface chemistry complete with quantitative elemental composition and chemical phase analysis of multiple complex phases, see the example of a complex, 3-chemical phase feldspar
- Differentiate surface chemistry with interior chemistry by analyzing as-received materials compared to freshly ground particles of material, argon ion sputtered material, or material analysis by XRF or by FTIR
- Great sensitivity to a very thin surface chemistry affecting particle bonding in a polymer matrix or agglomeration control surface treatments
- Used to determine and measure the degree of surface hydration
- Used to identify fill materials added to polymers following burn-off of the resin by TGA or other means
- When the sample quantity is very limited, it can perform an analysis when XRF does not see enough material
Organic Analysis by XPS or ESCA Surface Analysis:
- Examine filtered precipitates from organic liquids, determining the elemental composition and chemistry of the particle surfaces
- Examine residues of evaporated liquids and determine the elemental composition and chemical phases in the residues
Paper and Packaging Analysis by XPS or ESCA Surface Analysis:
- Determine the surface elemental composition and surface chemistry
- Identify the causes for printing and collating problems
- Identify the causes for adhesive bonding problems
- Determine the chemical nature of stains or aging and degradation
- Analyze surface coatings and surface treatments
- Analyze materials adsorbed onto the surface (adsorbants)
- Identify surface brightening particles
- Identify and measure surface contaminants
- Identify lubricants and anti-static coating materials
- Analyze filler inorganic particles after combustion of paper/polymer
Plastic and Polymer Analysis by XPS or ESCA Surface Analysis:
- Quantitative elemental and functional group chemical analysis of polymer surfaces
- Measurement of surface contamination including silicones
- Quantitative elemental & functional group analysis of surface treatments to affect such properties as coefficient of friction, dissipation of static charge, printability, changes due to sterilization or cleaning processes, adhesive bonding, friction bonding, reactivity, and degradation
- Identification of solid residue components due to fill materials after TGA burn-off of plastic, including borosilicate fiberglasses, silica, alumina, titanium dioxide, SiC, and minerals.
- Surface chemistry of fill materials prior to addition to polymer, which may affect resin wetting, agglomeration of particles, and migration to surfaces or interfaces
- Detection of components that segregate to the plastic surface, such as plasticizers, organic fire retardants, and fill particles with poor surface wetting properties
- Identify layer or interface of delamination or peeling and whether a contaminant is present there
- Investigate adhesive bonding failures due to surface segregation of plasticizer, inorganic fill particles such as talc, or migration of sodium from silica particle surfaces; or due to mold release agent or other contaminant; or due to stress in coating caused by internal layer contamination; or due to adhesive or primer degradation
- Polymer sealing problems
- Polyethylene fiber surface analysis with coating and after stripping the coating This is also an example of a report.
Semiconductor Analysis by XPS or ESCA Surface Analysis:
- Depth profile MBE-deposited multi-layer structures on GaAs
- Determine stoichiometry of sputter-deposited or MOCVD materials, such as silicon nitride and titanium nitride films, which are usually really silicon oxynitride or titanium oxynitride films
- Determine cause of soldering, bond pad, and adhesive bond difficulties
- Identify photoresist or wax residues, contaminants, and surface segregated impurities
- Measure thickness and determine uniformity of oxides, nitrides, or other film layers
- Depth profile multifilm contact structures on silicon or GaAs wafers
- Determine composition of thermal compounds or adhesives
- Evaluate the cleanliness of ceramic or plastic packaging materials
- Evaluate PCB laminate interfaces and surface conformal coatings
- Measure contamination on alumina feedthroughs and solve brazing problems
- Determine composition of electroplated gold and other metals, particularly on surfaces to which impurities migrate
- Chemistry of polyimide coating surface and effects on outgassing
- Identity cause of metallization layer delamination
- Detect and identify contaminants on connectors on plastic, ceramic, or pins
- Determine the cause of high contact resistance, such as nickel migration through gold to form NiO on the surface of the gold
- Determine causes of corrosion
General Services & Applications of XPS
Analysis Capabilities of XPS
XPS Surface Analysis Application Examples
- Detection and identification of surface contamination
- Failure analysis of adhesive bond failures to identify contamination, component ingredients migrated to the bonding interface, and bonding chemistry
- Highly sensitive and quantitative evaluation of facility silicone contamination using XPS analysis of exposed and returned test kit surfaces
- Identification of causes of corrosion or material degradation including conditions of very early initiation of corrosion
- Surface and near-surface characterizations of process-dependent material compositions
- Detection and identification of optical or abrasion resistant surface coatings and composition analysis to determine chemical stoichiometry
- Soldering, brazing, and welding problem resolution
- Polymer sealing problems
- Cause of intergranular failures in metal alloys
- Stoichiometry of deposited films or chemistry of reacted particle surfaces
- Materials surface composition changes due to chemical leaching, heating, radiation, or absorption
- Identification of unique surface phases of mineral level complexity common in inorganic materials, ceramics, glasses, and metal alloy oxides
- Interdiffusion and reactions at interfaces
- Evaluation of surface cleaning processes
- Medical device and prostheses wear, corrosion, brazing and welding, and contamination investigations
- Surface characterization while heating a material whose components react, outgas, or decompose with additional mass spectroscopy detection of vapor phases
- Semiconductor materials problems for epitaxial materials, bonding pads, barrier and oxide layers, see example of the surface chemistry analysis of an aged silicon oxynitride film
- Nanomaterials surface and interface characterizations
- Metal oxide composition as a function of depth, such as check for chromium enrichment in the surface oxide of stainless steels or to measure the degree of aluminum surface hydration
- Characterize optical coating multilayer structures, such as anti-reflective coatings
- Hard disk drive surface characterization
- Thin film delamination problems
- Environmental cleaning, scrubbing, and adsorbing media characterizations, such as smoke-stack scrubbing lime materials or activated carbon
- Protective coating problems due to mixing problems, segregation of component materials such as plasticizers, slip agents, or fire-retardant chemicals, environmental degradation, fill particle chemistry, and other problems often undertaken with other characterizations such as DSC, TMA, TGA, SEM/EDX, GC-MS, XRF, and optical microscopy
- Identification of fiberglass or other filler fiber and particle materials in plastics, pastes, and composite materials after the burn-off of the polymer matrix, commonly performed by TGA analysis
- Identify cause of adhesive failures at resin/fiber interfaces within fiberglass, carbon fiber, basalt fiber, silicon carbide or nitride or other reinforced composite materials
- Coating analysis, including surface chemistry difference from the bulk coating chemistry
- Chemical characterization of modified and treated surfaces, such as plasma treatments, acid etches and anodizations, and adhesion promoters such as silanes
- Determine bulk chemistry of minerals, ceramics, and glasses by examining freshly ground or fractured surfaces
- Identification of corrosion and wear deposits on hip and knee explants
- Identify the chemistry of gemstones
Case Histories
Industries that use XPS Routinely for Problem Solving and R&D
Engineering Materials, Chemicals, and Products Support Services |
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