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

We will extract small pieces from the wafer chip without breaking it and thin them down for high-resolution TEM observation and analysis. Furthermore, by cutting and preparing samples while leaving the areas to be analyzed, we will conduct TEM observation and analysis of the target areas from any desired direction and provide the data. Through advanced TEM sample preparation techniques, we will meet various observation, analysis, and evaluation needs.

In the method for preparing thin film samples for TEM observation using FIB, high-energy Ga ions (acceleration voltage of 30 kV) are used, resulting in the formation of a damage layer on the processed surface, which causes a deterioration in the image quality of the TEM. By performing processing at a lower acceleration (2 kV) than conventional methods, the damage layer can be reduced, leading to improved image quality. By reducing the damage on the FIB processed surface through low-acceleration FIB processing, high-quality and reliable data can be obtained in TEM image observation and EELS measurements.

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.

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.

For extremely thin films with a thickness of a few nanometers or less, such as natural oxide films on silicon wafers and silicon nitride thin films, we will measure the Si2p spectrum of the sample's surface. By performing waveform analysis on the obtained spectrum, we will determine the proportion of each bonding state and estimate the film thickness from this result and the average free path of photoelectrons (Equation 1).

The miniaturization of devices has increased the need for evaluating the depth distribution of impurities in extremely shallow regions. To conduct an accurate assessment, SIMS analysis using a primary ion beam with lower energy (below 1 keV) is required. Figure 1 shows examples of measurements of Si wafers implanted with BF2+ 1 keV, P+ 1 keV, and As+ 1 keV, using a primary ion beam energy of 250 eV to 300 eV.

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.

The uniformity of the film composition and the distribution of impurities, which are one of the elements in device creation, were evaluated using imaging SIMS analysis. Through data processing after measurement, we can obtain planar images (Figure 1), cross-sectional images (Figure 2), depth distribution profiles at arbitrary locations (Figures 3 and 4), and line profiles. From the distribution of constituent materials and impurities, we can gain information that leads to process and film quality improvements.

Polymeric materials such as polypropylene (PP) react with oxygen and moisture in the atmosphere when heated, causing changes in their molecular structure. Therefore, when foreign substances or contaminants may be present in polymeric materials, it is necessary to use standard materials processed in the same environment as the measurement sample for comparison data. To investigate how the PP standard material changes due to heat treatment (200°C for 30 minutes), FT-IR and TOF-SIMS measurements were conducted.

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

In semiconductor device manufacturing, it is necessary to remove metals remaining on the backside of the wafer from the perspective of improving yield, and it is important to quantitatively understand the amount of metal components remaining. To investigate the concentration distribution of metals remaining on the backside within a range of 500 µm from the bevel area, we conducted evaluations using TOF-SIMS. TOF-SIMS has the spatial resolution to detect metal components only near the bevel area, and by using standard samples with known concentrations, it is possible to quantitatively calculate the concentrations.

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.

We will introduce a case where the thickness of extremely thin films, such as natural oxide films on silicon wafers and silicon nitride thin films, which are less than a few nanometers thick, was calculated using XPS analysis. By measuring the Si2p spectrum of the surface of the Si wafer and performing waveform analysis on the obtained spectrum, we can determine the ratio of the presence of each bonding state, and from this result, it is possible to estimate the film thickness based on the average free path of photoelectrons (Equation 1). XPS allows for non-destructive and simple calculation of thin film thickness on substrates as broad average information.

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.

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.

We will introduce two measurement examples of effective failure analysis methods for GaN-based LEDs and high-frequency devices. By conducting lock-in thermal analysis on LED elements, it is possible to visualize the presence and timing of heat generation associated with light emission, allowing for the identification of specific areas that exhibit unique behaviors or characteristics. By performing emission microscopy observation on high-voltage, high-frequency devices, it is possible to capture the light emission associated with breakdown and identify areas with issues related to voltage resistance.

- 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.

XPS is a surface-sensitive technique, so carbon derived from organic contaminants due to the atmosphere is detected at a significant level. Reducing the influence of this carbon from organic contaminants is important for evaluating the original composition of the film. Typically, Ar ion sputtering is used to remove organic contaminants, but damage caused by sputtering may prevent the evaluation of the film's original composition and bonding states. We present an example where the influence of carbon from organic contaminants was reduced by removing the surface oxide layer using wet etching instead of Ar ion sputtering.

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.

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.

We disassembled a near-infrared VCSEL (vertical-cavity surface-emitting laser) implementation to extract a tiny chip, and after cross-section processing, we conducted SMM measurements. A high-resistance current confinement layer was observed surrounding the aperture of the VCSEL. Additionally, near the active layer, films of different materials were stacked, and this composition was measured as a contrast. Contrast was also confirmed within layers of the same composition, which is believed to reflect differences in carrier concentration and band bending.

GaN, which is being utilized as a power device and optical device, has a hexagonal wurtzite structure and exhibits crystallographic asymmetry (Ga polarity and N polarity) in the c-axis direction. The growth processes of epitaxial films differ between Ga polarity and N polarity, and the surface physical properties and chemical reactivity of the crystal also vary. In this document, the polarity of GaN was evaluated through annular bright field (ABF)-STEM observation. As a result, the positions of the Ga sites and N sites were identified, allowing for a visual clarification of the characteristics of Ga polarity and N polarity. Measurement method: TEM Product fields: Power devices, optical devices Analysis objectives: Shape evaluation, structural evaluation, thickness evaluation For more details, please download the document or contact us.

If you want to qualitatively evaluate metallic foreign substances, analyzing only the very surface may result in information about the oxide film present on the surface of the foreign substance, and you may not obtain information about the foreign substance itself. By performing depth analysis using TOF-SIMS, it is possible to evaluate the composition and state of the foreign substance located deeper than the oxide film. This document presents case studies evaluating the state of three locations that are believed to contain aluminum-based foreign substances.

In semiconductor device manufacturing, from the perspective of improving yield, it is necessary to enhance the cleanliness of the backside of the wafer and to remove substances that remain on the bevel area of the wafer. In this study, we conducted TOF-SIMS analysis of the bevel inclined surface to evaluate the distribution of contamination (Figure 2). Additionally, by comparing the mass spectra of the adhered substances with those of the normal area and the contamination source, we found that the adhered substances matched the metal (Cr) and organic components of the contamination source. TOF-SIMS can capture the contamination generation process in the bevel area (edge and inclined surface).

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.

This document presents case studies evaluating the diffusion layer of image sensors in smartphones. Using a scanning capacitance microscope (SCM) capable of determining the p/n type of semiconductors, we assessed the distribution of the diffusion layer. By combining the results from cross-sectional and planar SCM, we obtained complementary and extensive information. SCM is one of the effective tools for evaluating the quality of image sensor diffusion layers and for failure analysis.

We will introduce a case where lenses and CMOS sensor chips were extracted from commercially available smartphones and evaluated. Depending on the purpose, we created flat and cross-sectional surfaces through polishing and FIB processing, and confirmed the layered structure and layers using TEM and SEM. Furthermore, we identified the types of films using EDX. At MST, we can handle everything from disassembly to analysis in a consistent manner.

By measuring the sample, it is possible to evaluate the crystal structure through the combination of results obtained and simulations. This document introduces a case study in which the crystal structure is discussed by comparing the results obtained from HAADF-STEM and EDX measurements on polycrystalline neodymium magnets with simulated images using the respective measurement conditions. The combination of measurement results and computational simulation results allows for a deeper understanding of the crystal structure.

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.

Environmental Testing Evaluates the resistance of electronic components and devices when subjected to environmental stress. Reliability Evaluation Testing Assesses items related to the reliability and safety of the product.

High-resolution HAADF-STEM images reflect the atomic arrangement of crystals, and by simulating STEM images corresponding to various crystal orientations, they help in accurately understanding the relative orientations between crystal grains and the observed images in polycrystalline materials. This document presents a case where STEM images were simulated from the crystal orientation information obtained by the EBSD method for the crystal grains in a polycrystalline neodymium magnet, and compares them with actual high-resolution HAADF-STEM images.

Impurities from components of the film formation device, target materials, and plating solutions can contaminate the device and have adverse effects, making the qualitative assessment of impurities on surfaces, within films, and at interfaces important. TOF-SIMS can sensitively evaluate unknown elements present on surfaces, within films, and at interfaces in a single measurement due to the following three characteristics: 1. For metallic elements, ions from m/z 1 to 800 can be detected simultaneously in one measurement. 2. Detection sensitivity of a few ppm can be achieved (varies depending on materials and ions). 3. The use of a sputter gun allows for the evaluation of depth distribution.