一般財団法人材料科学技術振興財団　MST List of Products and Services

We will disassemble commercially available LED lighting, conduct composition analysis of each material, identify defects, perform physical analysis, and analyze impurities for energy-saving key devices.

Organic EL displays are advancing in practical applications by leveraging advantages such as high brightness, high-resolution color, and thinness due to their self-emissive principle. Organic EL devices are manufactured by stacking organic films, but analyzing the organic films in their stacked state has been challenging. This time, by using the XRR method, it has become possible to measure the film thickness and density of the organic films while maintaining the stacked state. Analysis of the thickness and density of stacked films is possible regardless of whether they are crystalline or amorphous.

Organic EL has advantages such as high brightness, high-resolution color, and thinness due to its self-emission principle, and it is expected to be one of the next-generation devices. Accurate analysis and evaluation of materials are crucial for improving characteristics, extending lifespan, and enhancing reliability; however, caution is required in handling them due to the use of highly reactive materials. A comparison between samples exposed to the atmosphere and those handled under a high-purity argon atmosphere confirms that oxidation (such as molecular ions +O, +OH, etc.) observed in atmospheric exposure is suppressed when handled in a high-purity argon environment.

We conducted TOF-SIMS analysis on an organic EL device (Figure 1) estimated to be formed from four layers of different organic compounds (or organometallic complexes) using XPS. For multilayer structural samples, depth profiling analysis using sputtering is also performed; however, in this case, we created a slope surface to expose each layer without breaking the bonds of the constituent components. Molecular weight-related ions and fragment ions presumed to be Alq3, NPD, and CuPc were obtained, confirming that TOF-SIMS analysis of the slope surface is an effective method for component analysis of organic multilayer films.

In SIMS analysis, it is essential to use standard samples with a composition close to that of the measurement sample in order to obtain more reliable concentration quantification values. By offering a wide range of AlGaN standard samples with varying Al content, we have been able to more accurately determine the impurity concentration in AlGaN, which is used in UV LEDs and UV sensors. We will present a case study where SIMS analysis of a UV sensor was conducted to quantify the concentration of the dopant, Si.

This paper presents a case study analyzing the degradation components of organic materials that deteriorate due to atmospheric exposure, using GCIB (Ar cluster). The experiment utilized the organic EL material, Rubrene. Measurements of the atmosphere-exposed samples using TOF-SIMS revealed the presence of a mass (m/z 564) estimated to be Rubrene peroxide, as well as low molecular weight benzene-related masses (m/z 77, 105). It was confirmed that these degradation-related components exist at depths of approximately 1μm or more from the surface. *GCIB: Gas Cluster Ion Beam

In SIMS analysis of layered structure samples, there is a concern that in structures where the layer of interest is located at a deep position from the sample surface, the depth resolution may degrade due to the influence of the concentration distribution of the upper layers. In such cases, it is effective to remove the upper layers through pretreatment before analysis. This document presents an example of selectively and progressively removing layers from InP/InGaAs-based SHBT (Single Heterojunction Bipolar Transistor) samples.

In general, the quantification of major elements with concentrations exceeding a certain percentage in SIMS is considered to be low. However, by using the M Cs+ (M: element of interest) detection mode with Cs+ as the primary ion, it is possible to determine the compositional distribution of major element elements in the depth direction. An example of depth compositional evaluation for Al, Ga, and In in GaN-based LED structures is presented.

It is possible to directly extract small pieces from the sample (micro-sampling) and perform FIB processing.

Organic EL displays are materials that hold the potential for high resolution and low power consumption, and market expansion is expected. In recent years, there has been a trend towards miniaturizing pixel arrangements to achieve higher image quality. When measuring small pixels, conventional oblique cutting TOF-SIMS measurements made it difficult to evaluate in the depth direction. However, by introducing GCIB (Ar cluster), it has become possible to evaluate organic EL materials in the depth direction with good reproducibility, even for small pixels, and to assess material degradation and diffusion as well. *GCIB: Gas Cluster Ion Beam

The Fast Fourier Transform Mapping method is a technique that performs a Fourier transform on high-resolution TEM images to analyze and visualize the minute lattice distortions of crystals from the spot positions of the FFT pattern. Through FFTM analysis, it is possible to (1) analyze lattice distortions in the x and y directions of the image, (2) analyze lattice distortions in the crystal plane direction, (3) analyze the distribution of crystal plane spacing and crystal plane orientation, (4) display the data distribution as a histogram, and (5) detect distortions of 0.5% with a spatial resolution of 5 nm. An example of its application to compound heterojunction multilayer film samples is presented.

Organic EL is expected to be a self-emitting, flexible next-generation display and lighting panel, but further improvements in reliability are desired. By combining various methods, comprehensive evaluations such as structural analysis, condition analysis, and identification of degradation causes can be achieved.

For membranes with low density, it is difficult to achieve contrast at high acceleration voltages (hundreds of kV) due to the high transmission capability of the electron beam. However, in low acceleration voltage SEM-STEM images, slight differences in density can be reflected, allowing for clear composition contrast. This can be applied to organic EL films, low-k films, gate oxide films, TEOS films, BPSG films, etc., where the differences in density, average mass, and composition are small. 1) STEM observation using SEM equipment with lower acceleration voltage compared to dedicated TEM equipment. Measurement methods: TEM, SEM Product fields: LSI, memory, display, solar cells, lighting Analysis purposes: Shape evaluation, film thickness evaluation For more details, please download the materials or contact us.

Pyrolysis GC/MS is a gas chromatography-mass spectrometer equipped with a pyrolysis device in the sample introduction section. For polymer materials that previously required complex pretreatment, samples can now be introduced into the GC for analysis without pretreatment by heating and decomposing them with the pyrolysis device. Additionally, by varying the temperature conditions of the pyrolysis device and the sampling conditions (double-shot method), it is possible to obtain two different types of information, such as additives and polymer materials, separately from the same sample, making the analysis of unknown polymer materials easier.

Polyimide is a material that is used in various fields, including electronic components, due to its high heat resistance and excellent electrical insulation properties. Since surface modification can enhance adhesion to other materials, it is important to understand the state of the modified layer. In this study, TOF-SIMS measurements were conducted under sputtering conditions that minimize the degradation of organic components, allowing for the evaluation of polyimide components in the depth direction. Using GCIB (Ar cluster) for sputtering enables the measurement of the targeted organic components in the depth direction. *GCIB: Gas Cluster Ion Beam

White LEDs have a long lifespan and are energy-efficient, leading to a rapid increase in demand in recent years, particularly for lighting applications. White LEDs emit light through a blue semiconductor chip, which then excites surrounding phosphors (mainly yellow) to produce white light. Therefore, in investigating the improvement of luminous characteristics and the causes of degradation, it is necessary to confirm the luminous characteristics of both the semiconductor chip and the phosphor. A micro photoluminescence (PL) device can confirm the luminous characteristics by targeting small areas.

Typically, SIMS measurements are conducted using chips with a flat surface of a few millimeters in size, but analysis can also be performed on small chips or samples with special shapes, typically less than 1 mm in size, by applying a fixed pre-treatment. Some samples that require investigation of trace components may have shapes that are not suitable for analysis under normal conditions, such as tiny chips or wire-like samples (Figure 1). In such cases, analysis is performed after fixation (Figure 2). Additionally, analysis may be possible for cross-sections, side surfaces, or samples with special shapes by applying pre-treatment.

From the perspective of cost reduction, the use of high-resistance Si substrates for power devices made of GaN is expected. However, it is said that if Al and Ga diffuse to the surface of the Si substrate during high-temperature film formation, a low-resistance layer is formed, leading to leakage. Therefore, we will introduce a case where SIMS analysis was conducted to evaluate the presence or absence of Al and Ga diffusion into the Si substrate. To accurately assess trace diffusion, measurements were conducted from the Si substrate side towards the GaN layer.

GaN-based LEDs have become widely used for lighting applications. To enhance the light extraction efficiency, textured surfaces may be created; however, these textures can lead to a degradation in depth resolution during depth analysis. We will present cases where flattening processing was applied to textured surfaces to mitigate the degradation of depth resolution and evaluate the depth concentration distribution, as well as cases where analysis was conducted from the backside (substrate side).

We will introduce a case where the depth concentration distribution of dopant elements such as Mg and Si in GaN-based LED structures was evaluated using multiple analysis modes. By selecting the optimal analysis mode according to the purpose in SIMS analysis, more precise evaluations can be achieved, so please feel free to consult with us.

SiC power devices are expected to reduce power loss and handle high power in a compact form as power conversion elements. The quality evaluation of SiC substrates, which is necessary for manufacturing these devices, has become a challenge. We propose a method to evaluate and quantify the crystal orientation, in-plane defect distribution, surface roughness, and impurities of SiC substrates, as well as to visualize these factors. Measurement methods: XRD, AFM, PL, SIMS Product fields: Power devices, lighting Analysis purposes: Trace concentration evaluation, structural evaluation, shape evaluation, failure analysis, defect analysis For more details, please download the materials or contact us.

In GaN-based LEDs, it is said that the diffusion of the dopant element Mg into the active layer leads to a decrease in luminous efficiency. This document presents a case study where SIMS analysis was conducted on GaN-based LED structural samples from both the surface side and the sapphire substrate side (back side) to evaluate the depth profile of Mg concentration.

Generally, in SIMS, the quantification of major elements with concentrations exceeding a certain percentage is considered to be low. However, by using the M Cs+ (M: target element) detection mode with Cs+ as the primary ion, it is possible to determine the compositional distribution of major elements in the depth direction. An example of depth compositional evaluation for Al and Ga in AlGaAs is presented.

In XPS analysis, in addition to the photoelectron peaks used for evaluation, photoelectron peaks from other orbitals and Auger peaks from X-ray excitation are also detected. Depending on the combination of elements, these sub-peaks can overlap with the target peak and interfere with the evaluation. *Typically, a strong photoelectron peak emitted from an inner shell level close to the outer shell is used. In the quantitative calculations of XPS analysis, the removal of such interfering peaks is primarily performed using the following two methods: 1. Removal using sensitivity coefficient ratios 2. Removal using waveform separation

Regarding foreign substance analysis, it has traditionally been difficult to analyze using microscopic FT-IR analysis or Raman analysis due to the influence of the substrate. However, with the introduction of micro-sampling tools, it has become possible to reduce that influence. We will introduce examples of analysis for two types of foreign substances.

- Photoluminescence measurement (PL measurement) can be conducted not only at room temperature but also by placing the sample in a cryostat for low-temperature measurements. Low-temperature measurements tend to show an increase in peak intensity and a decrease in peak full width at half maximum compared to room temperature measurements, which may provide insights into various energy levels. - Below, we will explain the precautions for low-temperature measurements and the differences in spectral shapes between room temperature and low-temperature measurements.

This text introduces an example of evaluating the composition and bonding states of GaN films used in LEDs and power devices using XPS. Understanding how the composition and bonding states change due to film formation conditions and surface treatments is effective for process management. It is important to appropriately select the X-rays used during the evaluation according to the purpose. Measurement conditions for each focus will also be presented.

In XPS analysis, the binding state evaluation of the material surface is conducted by observing the energy of photoelectrons obtained through X-ray irradiation. It allows for the assessment of whether metal elements are in an oxidized state, and for elements with significant energy shifts (chemical shifts) due to oxidation, it also enables the evaluation of the presence and proportion of multiple valences. Below are the main metal elements and oxides for which multiple valence evaluations are possible.

Self-assembled monolayers (SAMs), which are oriented organic films, have their functions and properties, such as surface wettability and adsorption, altered by orientation and orientation angle. Using XAFS with synchrotron radiation, it is possible to evaluate the orientation and orientation angle of organic film materials by analyzing the X-ray incidence angle dependence of peak intensity.

The electron diffraction method using an electron microscope is classified into three types based on the way the electron beam is incident on the sample. The characteristics of each type and examples of data are presented. It is necessary to choose the appropriate method according to the size of the evaluation object and the analysis purpose.

Organic EL (OLED) is used in various applications such as high-definition display panels and lighting, and the demand for layer structure analysis and degradation analysis is increasing. However, since it is formed by combining various organic materials, elemental analysis alone can only capture some phenomena. This document presents a case study where depth direction analysis data of OLED was obtained using TOF-SIMS and analyzed through MSDM (Mass Spectra Depth Mapping).

In depth profiling analysis using TOF-SIMS, if the positional information on the plane (x, y) is ignored, mass spectra exist at each depth (z), resulting in three-dimensional data of depth, mass, and spectral intensity. The visualization of this three-dimensional data as a single image is called MSDM (Mass Spectra Depth Mapping) representation.

Organic EL (OLED) is used in various applications such as high-definition display panels and lighting, and the demand for layer structure analysis and degradation analysis is increasing. However, since it is formed by combining various organic materials, elemental analysis alone can only capture a portion of the phenomena. This document presents a case study where depth direction analysis data of OLED was obtained using TOF-SIMS, and insights into the degradation of the sample were gained through MSDM (Mass Spectra Depth Mapping).

Epoxy resin is excellent in heat resistance, chemical resistance, and insulation properties, and also has high mechanical strength, making it suitable for various applications such as insulation materials for electronic devices, adhesives, paints, and construction materials. However, due to the lack of solvent solubility, the analytical methods for structural determination are limited. This case presents an example of thermal decomposition GC/MS measurement of epoxy resin used as a sealing material for LEDs. The thermal decomposition products reflecting the structures of the main agent and curing agent were obtained, and this resin was estimated to be a bisphenol A/anhydride type epoxy resin.

The band gap of thin film samples has been measured using analytical methods such as UV-Vis, PL, and XPS, but the cases that could be evaluated were limited due to constraints related to the sample structure, such as materials, film thickness, and substrates. This time, through the combined analysis of XAFS and XPS, it has become possible to reduce the constraints of the sample structure and achieve a higher precision band gap evaluation than before. This method is particularly effective for the evaluation of various oxide and nitride films. This document presents a case study on the band gap evaluation of silicon nitride (SiN) films. Measurement methods: XAFS, XPS. Product fields: solar cells, lighting, oxide semiconductors, power devices. Analysis purpose: evaluation of electronic states. For more details, please download the document or contact us.

Gallium nitride (GaN) is used as a material for LEDs and power devices due to its high thermal conductivity and high breakdown voltage characteristics. In its manufacturing process, the production of high-quality GaN crystals without crystal defects is required, making the assessment of damage from ion implantation and the degree of recovery an important evaluation criterion. This document presents a case study evaluating the damage caused by ion implantation into GaN substrates using XAFS. It is possible to detect disturbances in the crystal structure near the GaN surface, as well as N2 and interstitial N within the film, with high precision.

In fluorescent X-ray analysis (XRF), it is possible to easily evaluate element distribution and film thickness. In this case study, we will introduce an example of evaluating the thickness distribution of an Au film on a 4-inch Si wafer through multi-point mapping measurements. By performing multi-point mapping, we can calculate the Au film thickness using the FP (Fundamental Parameter) method from the XRF spectra at each point, allowing for the evaluation of thickness distribution based on the measurement coordinates.

To improve the reliability of organic EL, which is expected to expand in demand in the future, detailed structural analysis, state analysis, and identification of degradation causes will become increasingly important. We will introduce examples of evaluating layer structures and materials using TOF-SIMS and LC/MS. With TOF-SIMS, we were able to evaluate the layer structure and the component information of each layer. We conducted analyses of the components revealed by TOF-SIMS using LC/MS and a fluorescence detector, allowing us to assess the emission wavelength and understand the structure of the components. Thus, the combination of TOF-SIMS and LC/MS enables detailed evaluations.

Soft X-ray emission spectroscopy (SXES) using synchrotron radiation is widely used as a method to evaluate the electronic states of materials because it allows for the direct acquisition of the partial density of states (pDOS) near the Fermi level for each element constituting the material. Furthermore, the characteristics of this method include: 1. Information from the bulk can be obtained, 2. It can be evaluated without being affected by charging effects even for insulators, and 3. It has a low detection limit (less than 1 atomic %), making it particularly effective for evaluating materials containing light elements (such as B, C, N, O). In this document, we will introduce the SXES spectrum of a GaN substrate as a measurement example.

Understanding the band structure, including valence bands, conduction bands, and gap states, is an extremely important evaluation criterion for controlling various properties of materials. However, there are limited analytical methods available for direct and detailed assessment of these aspects. Simultaneous measurements of X-ray absorption spectroscopy (XAS) and X-ray emission spectroscopy (XES) using synchrotron radiation allow for a comprehensive understanding of the band structure, as well as detailed information regarding the attribution of the elements and orbitals that compose it. This document presents the XAS and XES spectra of GaN substrates as an example of measurement.

When designing and controlling the properties of various materials, it is very important to clarify the types and amounts of elements present in trace amounts in the base material, as well as their states of existence. The types and amounts of elements can be evaluated using methods such as SIMS (Secondary Ion Mass Spectrometry) and ICP-MS (Inductively Coupled Plasma Mass Spectrometry), but the evaluation of states of existence, such as valence and chemical bonding states, is effectively conducted using XAFS (X-ray Absorption Fine Structure) measurements with synchrotron radiation. This document introduces a case study where the valence of trace amounts of Ce in ceramic materials was evaluated as a measurement example.

To investigate the causes of defects such as poor adhesion, it is important to gain insights into the surfaces of wafers and devices. In this instance, hydrophobic areas were observed on a silicon wafer, prompting wide-area imaging using TOF-SIMS. As a result, components estimated to be silicone oil, CF-based grease, and paraffin oil were identified from the hydrophobic areas. TOF-SIMS typically has a measurement field of view up to 500μm square, but by moving the stage during measurement, it is possible to evaluate wide-area distributions. Measurement method: TOF-SIMS Product fields: Devices, Displays, Electronic Components, Manufacturing Equipment Analysis objectives: Qualitative, Imaging, Composition Distribution Evaluation For more details, please download the materials or contact us.

To determine impurity concentrations using SIMS analysis, it is necessary to use a standard sample with the same composition as the analysis sample. By preparing various Al compositions of AlGaN standard samples for AlGaN used in ultraviolet LEDs and power devices, MST can achieve more accurate quantification of impurities. We will introduce a case where, after disassembling a commercially available deep ultraviolet LED, SIMS analysis was conducted to determine the concentration of the dopant Mg and the distribution of the main component Al composition. Measurement method: SIMS Product fields: Lighting, power devices, optical devices Analysis purposes: Trace concentration evaluation, impurity evaluation, distribution evaluation, product investigation For more details, please download the materials or contact us.

Quantum chemical calculations can provide molecular insights (such as molecular structure, charge distribution, molecular orbitals, and mechanisms of chemical reactions) that serve as guidelines for the development and design of materials, as well as simulate various response spectra like UV-Vis and NMR with high accuracy. The results obtained can help overcome various challenges faced in research and development in fields such as functional materials and drug discovery. This document introduces the analysis targets, the physical property information obtained, and case studies that can be understood from quantum chemical calculations.

Pigment Red 254 (p-Cl DPP) is a type of DPP (diketopyrrolopyrrole) pigment that exhibits a vivid red color. DPP pigments are used as red pigments with excellent weather resistance, and due to their ease of mass production and low cost, they are also expected to be utilized as organic EL materials. This document presents a case study of UV-Vis spectrum simulation based on quantum chemical calculations targeting Pigment Red 254 in solution. By referring to the simulation results, the spectral shape of the measured data can be interpreted. Measurement method: Computational science and data analysis, UV-Vis Product fields: Lighting, displays, cosmetics, daily necessities Analysis purpose: Evaluation of chemical bonding states For more details, please download the document or contact us.