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

In the development of ultra-high voltage, low-loss SiC power devices that can be used in substations, controlling low carrier concentration is necessary, and SIMS analysis is effective for evaluating extremely low concentrations of impurities. In SIMS analysis, it is possible to evaluate extremely low concentrations by limiting the impurities to one element without simultaneously acquiring multiple elements. This document presents analysis examples that evaluate the extremely low concentration range of impurities in SiC with ultra-high sensitivity, which has been difficult to assess conventionally.

Gallium oxide (Ga2O3) has a higher band gap and superior physical properties compared to SiC and GaN, making it a material of interest for power devices that can be expected to be high-efficiency and low-cost. Controlling the impurity concentration, which affects the characteristics, is crucial in wafer development. This document presents a case study of impurity concentration analysis in Ga2O3 films. It is found that B and C are below the background level, while Si is present. MST offers a range of Ga2O3 standard samples and can quantify over 30 types of impurities.

In the fabrication of Si-based semiconductor devices, various processes such as ion implantation and annealing are performed. It is considered important to confirm the degree of irradiation defects and the extent of crystallinity recovery before and after these processes in order to control the manufacturing process. Photoluminescence (PL) measurements at low temperatures are one effective means of investigating these aspects. An example of PL measurements of samples that underwent ion implantation on a Si substrate followed by annealing treatment is presented.

Gallium oxide (Ga2O3) has a wider bandgap than SiC and GaN, and possesses excellent physical properties, making it a material of interest for high-efficiency, low-cost power devices. Controlling the impurity concentration, which affects the characteristics, is crucial in wafer development. This document presents a case study of quantitative analysis of metal elements in the vicinity of Ga2O3 films. TOF-SIMS allows for highly sensitive evaluation even in very shallow regions.

Silicon oxide films are widely used as gate dielectrics in MOS devices and as anode materials in lithium-ion secondary batteries, but it is known that the presence of intermediate oxides and the bonding states at the interface have a significant impact on device characteristics. XAFS measurements using synchrotron radiation can detect information from a depth of several tens of nanometers from the sample surface, allowing for non-destructive analysis of the structure and bonding states in both bulk and at the interface. This document presents a case study investigating the presence of intermediate oxides in silicon oxide films using XAFS.

A cross-section of the SiC Planer Power MOSFET was fabricated, and the p/n polarity distribution of the diffusion layer was evaluated using SCM (Scanning Capacitance Microscopy), while the carrier concentration distribution was qualitatively assessed using SMM (Scanning Microwave Microscopy). From both sets of data, it was found that a p-type Body layer is formed in a two-layer structure around the n+ type Source layer, and that a Channel Epitaxial layer exists directly beneath the gate. At the edge of the Channel Epitaxial layer, a partial decrease in concentration was observed in the Source layer.

SRA can analyze the depth profile of carrier concentration distribution over a wide range from shallow regions (a few hundred nm) to deep regions (a few hundred μm). It is also possible to evaluate the in-plane distribution of resistance values at the sample surface or at specified depths. As an example, we will introduce a case where the depth profile of carrier concentration distribution for a commercially available Si-IGBT chip was evaluated, including the entire chip, the field stop layer, and the lifetime killer, as well as the in-plane distribution of resistance values at the irradiation depth of the lifetime killer using SRA.

It is known that the adsorption of organic substances on the wafer surface can lead to various issues, such as the degradation of gate oxide film breakdown voltage. Therefore, as the miniaturization and high integration of semiconductor devices progress, it has become increasingly important to monitor not only inorganic substances but also trace amounts of organic substances. Here, we present a case where silicon wafers were stored in two types of wafer cases, and the organic contamination components adhered to the entire wafer surface were concentrated using a wafer analyzer and evaluated using GC/MS.

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.

TDS is a method that heats samples in high vacuum (1E-7 Pa) and detects the gases that are released. By heating the sample at a constant rate in high vacuum, it is possible to confirm the temperature dependence of even trace amounts of desorption (at the monolayer level). Additionally, for some components, it is also possible to calculate the number of molecules of the desorbed gas. We will introduce examples of TDS applied to representative materials.

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 the manufacturing process of these products, it is essential to produce high-quality GaN crystals without crystal defects that can affect device characteristics. This document presents a case study evaluating the crystal state of samples in which c-GaN crystals were grown at high speed on c-plane GaN substrates (c-GaN substrates).

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), a simple evaluation of elemental distribution is possible. In this case study, we used a deposition device to create films of arbitrary amounts of Au on 4-inch Si wafers A and B as samples, and compared the distribution and total amount of Au. The results of the surface analysis confirmed the distribution state of Au (Figures 1-4). Additionally, by comparing the adhesion amounts based on the Au intensity from the XRF spectra obtained from each pixel, we confirmed that wafer B had more Au than wafer A (Figure 5).

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.

IGBT (Insulated Gate Bipolar Transistor) is used in various products as a power semiconductor module, ranging from home appliances to industrial equipment. Lifetime control is implemented for performance improvement in IGBTs, but this control is achieved by creating defects (lifetime killers) in the drift layer. By conducting low-temperature micro-PL analysis from the cross-section, it is possible to gain insights into lifetime killers.

When ions or electron beams are irradiated onto Si, a portion of the "substitutional carbon" that is slightly contained in Si changes into "interstitial carbon." This interstitial carbon is believed to influence the electrical properties of the device. The behavior related to interstitial carbon can be observed very sensitively through low-temperature PL analysis, allowing insights into trace amounts of carbon below the detection limit of SIMS analysis. This document presents examples of low-temperature PL analysis and SIMS analysis conducted on Si substrates subjected to ion implantation.

In PL (photoluminescence) mapping, it is possible to identify the positions of crystal defects from the luminescent areas. Furthermore, by performing high-resolution STEM observation (HAADF-STEM images) at the same locations, we can capture stacking defects. In this case study, we investigated commercially available SiC power devices using PL mapping and STEM. After identifying the positions of stacking defects through PL mapping, we conducted μ-sampling at the defect edge and performed cross-sectional STEM observation.

In the manufacturing process of semiconductor devices, various adhesive sheets, such as dicing tape, are used. Adhesive sheets can be a source of foreign substances and contamination. Therefore, in this case study, we will present the results of a comprehensive evaluation using TOF-SIMS and SWA-GC/MS. With TOF-SIMS, by conducting qualitative analysis of each adhesive sheet material, it is possible to identify which adhesive sheet is responsible for foreign substances and contamination, as well as which layer of the adhesive sheet is the source. Additionally, SWA-GC/MS allows for quantitative confirmation of which adhesive sheet has the least contamination.

XPS is a method for obtaining information about the composition and bonding state of the sample surface (to a depth of about several nanometers), but by combining it with ion irradiation for sputter etching, it is also possible to evaluate the internal structure of the sample and depth distribution. However, in evaluations involving sputter etching, due to the principles and measurement mechanisms of XPS, the amount of oxygen may be overestimated due to the influence of adsorbed oxygen, so caution is required. In the case of evaluating samples that easily adsorb oxygen (such as Ti, TiN, AlN, etc.) or focusing on trace amounts of oxygen, the influence of adsorbed oxygen becomes significant, so comparisons between samples and analyses using SIMS are recommended.

In clean rooms where the manufacturing of semiconductors and liquid crystals takes place, it is important to monitor not only particles but also molecular-level chemical contamination (molecular contamination). Floating molecular contaminants include acidic and basic gases, cohesive organic substances, dopants, and metals, and the analysis methods vary depending on the components. Here, we will introduce details about cohesive organic substances and the representative collection methods, "adsorbent collection" and "wafer exposure collection."

The peaks in the Raman spectrum of single crystal Si shift to higher wavenumbers when compressive stress is applied to the sample and shift to lower wavenumbers when tensile stress is applied. This allows us to gain insights into the stress in Si. An example is shown where the distribution of stress in the cross-section of an IGBT (Insulated Gate Bipolar Transistor) was confirmed using Raman mapping.

In SNDM (Scanning Nonlinear Dielectric Microscopy), it is possible to identify the p/n polarity of semiconductors and visualize the shape of the diffusion layer. This method encompasses the functions of the traditionally used SCM (Scanning Capacitance Microscopy), allowing for sufficient evaluation of next-generation power devices, such as SiC, which are difficult to assess with SCM, from low to high concentrations. It is characterized by high sensitivity and can be applied to all compound semiconductor devices. As an example, we will introduce a case where a cross-section of a SiC Planer Power MOS was fabricated and analyzed using SNDM.

In investigations of competitor products and inspections of defective items, an internal structural examination is necessary first. X-ray CT allows for non-destructive acquisition of transmission images from within the sample, enabling three-dimensional reconstruction. This document presents a case study where a discrete package equipped with SiC chips was observed using X-ray CT as part of a product investigation. After confirming the structure with X-ray CT, we propose conducting physical analysis (failure analysis) using MST.

In recent years, SiC has been attracting attention as a material for high-voltage devices. The trench MOSFET structure is necessary for the high integration of devices, and the application development for SiC devices is progressing. Since the channel region of the trench MOSFET structure is the trench sidewall, the flatness of the trench sidewall is related to the reliability of the device. This document introduces an example of quantitatively evaluating the roughness of the trench sidewall of SiC trench MOSFETs using AFM (Atomic Force Microscopy).

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.

In recent years, SiC has attracted attention as a material for high-voltage devices. The trench MOSFET structure allows for high integration of the elements, and applications for SiC devices are also being advanced. On the other hand, there are challenges regarding the dopant activation rate of SiC devices, making performance evaluation important. In this instance, we will introduce a case where carrier polarity determination was conducted using SNDM (Scanning Nonlinear Dielectric Microscopy) and carrier concentration distribution was evaluated using SMM (Scanning Microwave Microscopy) for SiC trench MOSFETs.

β-Ga2O3 has a wide band gap and is expected to be a promising material for next-generation power devices and oxide semiconductors in terms of excellent power transmission efficiency and cost reduction. In recent years, it has been reported that β-Ga2O3 can be n-doped with Si or Sn. In this study, we conducted structural optimization calculations for models of β-Ga2O3 doped with Si or Sn and evaluated which sites each dopant is more likely to occupy in the crystal. Subsequently, we calculated the density of states from the obtained structural models and investigated the changes in electronic states due to doping.

The siloxane that is emitted as outgassing from silicone products is a component that is volatile and tends to adhere to substrates. It is known that when siloxane adheres, it can cause adverse effects such as fogging of optical system lenses, delamination or poor adhesion of films, and contact failures in relay circuits, making it important to investigate the amount of siloxane outgassing. This document presents a case study on the amount of cyclic dimethylsiloxane generated when heating silicone tubes at 200°C.

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.

Rietveld analysis is a method for analyzing measurement data from XRD (X-ray diffraction) and neutron diffraction. In addition to identifying lattice constants and space groups using existing methods, it is possible to obtain more detailed crystallographic information, such as atomic arrangements within the unit cell, if there is a crystal structure model (candidate) for the sample.

We provide suitable analysis menus for essential components of EVs, including onboard batteries and devices.

Carrier lifetime refers to the time it takes for minority carriers among the excess carriers generated during the operation of electronic devices to decay to 1/e. Proper control of this is important for managing the electrical characteristics of the device. On the other hand, luminescence lifetime indicates the time until the luminescence intensity from the sample reaches 1/e, and it can be calculated from the luminescence decay curve. Since some minority carriers emit light during recombination, it is possible to indirectly evaluate the carrier lifetime from luminescence lifetime measurements. This document presents a case study on the evaluation of carrier lifetime for 4H-SiC epitaxial substrates. Measurement method: Fluorescence lifetime measurement Product fields: Power devices, LSI/memory, electronic components Analysis purposes: Failure analysis, defect analysis, product investigation, carrier lifetime, process evaluation For more details, please download the document or contact us.

Impurities contained in semiconductor materials can affect product quality, leading to issues such as leakage current and early device failure. Therefore, understanding the amount of impurities in the materials is crucial for improving product quality. This document presents a case study on SiC substrates, which are gaining attention as power device materials, analyzing impurities adhered to the substrate surface using ICP-MS and impurities within the substrate using GDMS. Measurement methods: ICP-MS, GDMS Product fields: Power devices, manufacturing equipment, components Analysis purpose: Trace concentration evaluation For more details, please download the document or contact us.

In electronic devices that use a lot of semiconductors, each component is mounted by soldering. If defects occur in the solder joints, it can lead to malfunctions in the electronic devices. Therefore, evaluating the wettability of solder is important for assessing the reliability of components. In this study, we artificially degraded the samples to examine how the wettability of the solder changes. After the constant temperature and humidity test, it was found that the wettability of the electrode surface changed. Measurement methods: Constant temperature and humidity test, solder wettability test Product fields: Power devices, LSI/memory, electronic components Analysis purpose: Degradation investigation, reliability evaluation For more details, please download the materials or contact us.

GaN-based high electron mobility transistors, known as GaN HEMTs (High Electron Mobility Transistors), utilize an AlGaN/GaN heterostructure to achieve a two-dimensional electron gas layer (2DEG), resulting in high electron mobility. They are used in applications such as fast chargers, leveraging these characteristics. This document presents the disassembly and evaluation of normally-off GaN HEMT devices. We will introduce a case study that employs a combination of analytical methods to gather comprehensive insights about the samples. Measurement methods: SIMS, TEM, SCM, SMM. Product field: Power devices. Analysis objectives: Trace concentration measurement, shape evaluation, film thickness evaluation, structural evaluation, product investigation. For more details, please download the document or contact us.

Power devices are attracting attention from the perspective of power and energy conservation as switches for high voltage and large current. In power devices, wiring defects and electrical failures occur due to the application of high voltage. Additionally, identifying and analyzing the causes of defects is essential for improving product reliability. This document presents a case study where the identification of defective areas was conducted using EMS (Emission Microscopy Method), and the analysis of defect causes was evaluated using SCM (Scanning Capacitance Microscopy) and SEM (Scanning Electron Microscopy). Measurement methods: EMS, SCM, SEM Product field: Power devices Analysis purpose: Failure analysis and defect analysis For more details, please download the document or contact us.

Gallium nitride (GaN), a wide bandgap semiconductor, is used in a wide range of fields such as power devices and communication/optical devices. When fabricating devices, the shape and roughness of the wafer surface significantly impact device performance. During the growth of GaN wafers, a step-terrace structure is formed on the surface due to stress effects from lattice mismatch with the supporting substrate. This document introduces a case where the step-terrace structure of the GaN substrate surface was visualized using AFM, and the terrace width, step height, surface roughness, and off-angle were evaluated. Measurement method: AFM Product fields: Power devices, electronic components, lighting Analysis purpose: Shape evaluation, structural evaluation For more details, please download the document or contact us.

For the SiC transistor, where the leak location was identified using a backside emission microscope, cross-sectional SEM observation was conducted using Slice & View. With Slice & View, it is possible to capture images of the leak location without missing it by performing cross-sectional observations at a pitch of several tens of nanometers around the leak area. By converting the SEM images into 3D, the leak path can be confirmed. Measurement method: Slice & View, EMS Product area: Power devices Analysis purpose: Failure analysis, defect analysis, product investigation For more details, please download the materials or contact us.

We conducted Slice & View on a SiC transistor where the leak location was identified using a backside emission microscope, and performed magnified observation and SEM-EDX analysis at the confirmed destruction site. Bright contrast was observed in the reflected electron images, indicating the segregation of Si and Ni. It is believed that some segregation of elements such as Si and Ni occurred due to the destruction caused by the leak. Measurement methods: Slice & View, SEM-EDX, EMS Product field: Power devices Analysis purpose: Failure analysis, defect analysis, 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.

In HAXPES, hard X-rays (Ga radiation) are used for excitation, which results in different positions of the Auger peaks compared to the Al and Mg radiation typically used in standard XPS measurements. Therefore, even in samples where the photoelectron peaks and Auger peaks overlap in Al and Mg measurements, this overlap can be avoided in Ga measurements, allowing for a detailed evaluation of the bonding states. This document presents the spectra of Kovar (an alloy of Fe, Ni, and Co) and GaN measured using Ga radiation (equipped with HAXPES) and Al and Mg radiation (equipped with XPS).

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.