LA-ICP-MS of thin film samples

Rutherford Backscattering Spectrometry (RBS) can be used to measure the composition of solid samples quantitatively at the surface as well as depth profiling. RBS is used for the analysis of heavy elements and can be combined with ToF-ERDA when lighter elements also need to be analyzed. Elements with similar mass can be difficult to differentiate.

Time-of-Flight Elastic Recoil Detection Analysis (ToF-ERDA) measurement for determining the elemental concentrations of thin films. ToF-ERDA is capable of identifying all elements, including various hydrogen isotopes. It provides elemental depth profiles by determining the concentration of each element at different depths within a sample. Typically, the method achieves detection limits ranging from 0.1 to 0.5 atomic percent and depth resolution between 5 and 20 nm. It is suitable for analyzing films with thicknesses between 20 and 500 nm. For accurate measurements, the sample surface should be smooth, with a roughness of less than 10 nm. The method is inherently quantitative when analyzing thin films on typical substrates, such as silicon (Si), gallium nitride (GaN), silicon carbide (SiC), gallium arsenide (GaAs), or indium phosphide (InP). So, reference samples are not needed to obtain quantitative results. The technique is particularly useful when analyzing light elements due to its good detection limits. In addition to typical ToF-ERDA measurements, we also offer LI-ERDA (also referred to as Foil ERDA) for more precise determination of hydrogen isotopes. The detection limits with LI-ERDA are typically around 0.01 atomic percent, and depth resolutions of ~1nm can be achieved. LI-ERDA only allows detection of hydrogen isotopes.

X-Ray Reflectometry (XRR) analysis is used to measure the density (g/cm3), thickness (nm), and roughness (nm) of thin films. The method is applicable to the characterization of single- or multilayered thin films, as it provides information on the thickness and density of individual layers of the sample material as well as the roughness of the interphases. Greatest accuracy for XRR thickness measurements is generally achieved for samples containing 1-150 nm thick surface layers with under 5 nm RMS roughness. Thicker films and coatings with rougher surfaces can also be characterized, but the accuracy of thickness determination decreases as the thickness and roughness of the film or film stack increase. >150 mm wafers are typically cut to fit the sample holder. Please let us know if you need testing for larger wafers that cannot be cut into pieces. The available temperature range for XRR measurements is 25-1100 °C, and crystallinity can be studied as a function of temperature. The measurements can be performed under a normal atmosphere, inert gas, or vacuum. Measurements are typically performed using one of the following instruments: Rigaku SmartLab, Panalytical X'Pert Pro MRD, Bruker D8 Discover. Please let us know if you have a preference for a specific instrument.

During this analysis, the surface of a smooth and hard sample is imaged with an atomic force microscope (AFM). Topological images are typically provided from three locations around the sample. The measurement area is 5 x 5 micrometers, if not otherwise agreed. Measurements are typically done using the following instrument: Bruker Dimension Icon.

VPD ICP-MS allows the determination of trace metal contamination on the surface of wafers. The full surface of the wafer is scanned during the analysis. VPD ICP-MS is performed using acid to dissolve the top surface of the wafer before the determination of elemental concentrations with ICP-MS. Please note that lighter elements, such as H, C, N, O, and F, cannot be analyzed. We offer different analysis packages for a wide range of elements: 30 elements: Al, As, B, Ba, Be, Bi, Ca, Cd, Co, Cr, Cu, Ga, Ge, Fe, K, Li, Mg, Mn, Mo, Na, Ni, Pb, Sb, Sn, Sr, Ti, W, V, Zn, Zr, 41 elements: Al, As, B, Ba, Be, Bi, Ca, Cd, Co, Cr, Cs, Cu, Ga, Ge, Fe, Hf, Ir, K, Li, Mg, Mn, Mo, Na, Nb, Ni, Pb, Re, Sb, Sn, Sr, Ta, Te, Th, Ti, Tl, U, W, V, Y, Zn, Zr, Additional noble metals: Ag, Au, Pt, Pd, Additional elements are available upon request, Detection limits are in the ppm–ppb range (107–1010at/cm2). This measurement is primarily intended for 100, 150, 200, and 300 mm bare-silicon wafers, but we also offer ICP-MS analyses for other wafer sizes and thin films. The most typically used instruments include the following: Perkin-Elmer NexION 350S ICP-MS, Perkin-Elmer Sciex ELAN 6100 DRC II ICP-MS, Thermo Fisher iCAP TQe ICP-MS, Finnigan element2 ICP-MS. Contact us for more information and to request a quote.

XPS is a semi-quantitative technique used to measure the elemental composition of material surfaces. In addition, it can also determine the binding state of the atoms. XPS is a surface-sensitive technique. Typical probing depth is 3-9 nm, and detection limits range roughly between 0.1 and 1 atomic %. XPS can measure elements from Li to U. The elemental composition is reported in at.% and measured on 1 area of a few 100 µm. Upon request, we can measure smaller areas or depth profiles, and a binding state determination can also be provided. Measurements are typically performed using one of the following instruments: PHI Genesis, Thermo Fisher ESCALAB 250Xi, PHI Quantum 2000. Synchrotron XPS is also available. Contact us for more information and a quote for your project.

Grazing incidence X-ray diffraction (GI-XRD) measurement for thin films and surface layers. The measurement provides the following information: XRD spectrum and identification of the phase(s), Crystallinity, crystallite size, lattice parameters, and strain of the phase. NOTE that these parameters are determined if the samples are highly crystalline. It may not be possible to determine them if the crystallinity is insufficient.. Best GI-XRD results are typically achieved for samples containing up to 300 nm thick surface layers with under 10 nm RMS roughness. Thicker films and coatings with rougher surfaces can also be characterized, but the quality of the data is generally lower for rough samples, and the sample properties below 300 nm depths are typically not reflected in the results. One of the following instruments is typically used to perform the measurements: Rigaku SmartLab, Panalytical X'Pert Pro MPD, Bruker D8 Discover, Malvern Empyrean. By default, the GI-XRD is conducted in ambient conditions, but temperatures of 25 to 1100 °C can be used to study crystallinity as a function of temperature. The measurements can also be performed under inert gas or vacuum if needed. Please contact our experts to discuss the available temperature and atmosphere combinations.

Group delay dispersion (GDD) and group velocity dispersion (GVD) are critical parameters for understanding how the propagation time and speed of light pulses change with frequency or wavelength as they travel through transmitting media, such as glass optics, or interact within the layers of thin-film coatings. Group delay refers to the time delay experienced by light of various frequencies, while group velocity is the speed at which the envelope of a pulse propagates through a medium. GDD and GVD characterize the rate at which group delay and group velocity, respectively, vary with the frequency or wavelength of light. GDD and GVD are expressed in units of time squared, typically in femtoseconds squared (fs2). Both can be measured using a white light interferometer. The measurement conditions for which we can perform the test are outlined below. For a 1" sample Reflection optics AOI: 0° & 5-70°, Transmission AOI: 0-70°. For a 2" sample Reflection optics AOI: 5-70° (0° could be possible, discuss with expert), Transmission AOI: 0-70°. Spectral coverage: 400-1060 nm (VIS/NIR basic version), 250-1060 nm (UV/VIS/NIR version), 900-2400 nm (IR version). To carry out the testing, the following measurement details and sample information should be available: Sample matrix: Substrates, coating, etc. , Reflection/transmission angle of incidence: Reflection AOI of 45°, Transmission AOI of 45°, etc., Polarization: p, s, N/A, Working wavelength range, Measurement points: How many and where in the sample?, Expected GDD/GVD.

Imaging of the sample with transmission electron microscopy (TEM) and determination of the elemental composition of the sample using electron dispersive X-ray spectroscopy (EDX or EDS). Several images with varying magnifications are taken to get a good overview of the sample. An EDX mapping, line scan, or point measurement is collected to measure the sample composition (elemental at.% or wt.%). For solid samples, the analysis often requires FIB preparation, which is priced separately. HR-TEM can also be provided. Contact us for more details about the analysis options.

Measurement of surface profile, roughness or edge sharpness by optical profilometry.