Vol. 78, No. 1, January 2023

Special Reports

Technologies for Electronic Devices and Materials Making Contribution to Carbon Neutrality

MORI Seiichi

KAWAGUCHI Yusuke / IKEDA Sadao / YAMAMOTO Kotaro / NABA Takayuki

To address the pressing issue of global warming, Japan and many other countries are aiming to realize carbon neutrality by 2050 by achieving net zero emissions of greenhouse gases, which are considered to be the predominant cause of global climate change.

The Toshiba Group is developing and continuously improving the performance of a broad range of device and material products that improve the energy efficiency of various systems in order to reduce carbon dioxide (CO2) emissions. Through these efforts, we are contributing to the achievement of carbon neutrality by 2050.

KAGANOI Keisuke / SUZUKI Miwako / KANEKO Atsushi / SHIMAMURA Shinya

Data centers and communication base stations have recently become one of the largest consumers of electric power as a result of the ongoing increases in the volume of data communication and storage capacity. Reduction of the power consumption of power devices in the power supplies of such facilities is therefore an issue of vital importance in the context of achieving carbon neutrality.

Toshiba Electronic Devices & Storage Corporation is engaged in activities to realize loss reduction in power metal-oxide-semiconductor field-effect transistor (MOSFET) products. Reduction of the reverse recovery loss is essential in order to reduce the total loss of power MOSFETs. We have now released a 150 V power MOSFET fabricated using the U-MOSX-H process and a 650 V power MOSFET fabricated using the DTMOSVI process. In addition to improvements in the conventional methods for achieving smaller on-resistance (Ron) and smaller gate charge, these devices provide a substantial improvement in reverse recovery characteristics, achieved by the optimization of lifetime control techniques, in order to enhance the efficiency of power supplies used in data centers and communication base stations.

IWAKAJI Yoko / GEJO Ryohei / YAMAKAWA Yuji / SAKANO Tatsunori

In recent years, insulated gate bipolar transistors (IGBTs) have become widely used in a variety of products ranging from home appliances to power conversion equipment as high-voltage and low-loss power devices.

In order to achieve a carbon neutral society, Toshiba Electronic Devices & Storage Corporation has been developing multigate control techniques for IGBTs with the aim of further reducing their total power loss. Multigate control makes it possible to drastically reduce switching losses while keeping conduction losses low. From the results of experiments using prototype devices, we have confirmed that multigate control achieves reductions in turn-off loss (Eoff) and turn-on loss (Eon) by 27% and 50%, respectively, in the case of 1 200 V-class IGBTs, as well as reductions in Eoff, Eon, and reverse recovery loss (Err) by 24%, 18%, and 32%, respectively, in the case of 4 500 V-class reverse-conducting injection-enhanced gate transistors (RC-IEGTs), compared with the conventional single-gate controlled devices of each type.

FURUKAWA Masaru / SHIMIZU Yasuhiro / KOBAYASHI Masakazu

Although silicon carbide (SiC) holds promise as a key semiconductor material for realizing power metal-oxide-semiconductor field-effect transistors (MOSFETs) with higher voltage and lower loss compared with Si MOSFETs, problems regarding the reliability of SiC MOSFETs are a critical issue.

Toshiba Electronic Devices & Storage Corporation has responded to this situation by developing SiC MOSFETs in which reliability is improved by means of an embedded Schottky barrier diode (SBD). However, the embedded SBD reduces the area available for the functioning of the MOSFET, thereby degrading the performance of SBD-embedded SiC MOSFETs. To resolve this issue, we have now developed third-generation SBD-embedded SiC MOSFETs that succeed in achieving a balance between improvement of reliability and reduction of switching loss due to the adoption of a newly designed device structure.


Technology computer-aided design (TCAD) simulators for silicon carbide (SiC) power semiconductors have not yet been sufficiently developed compared with those for silicon (Si) power semiconductors. For example, the behaviors of carbon vacancies (VC), which are well known as detrimental point defects in SiC, in fabrication processes including impurity ion implantation and activation annealing are not yet modeled in commercial TCAD simulators. In addition, although models respectively simulating the behavior of VC in the relatively low-temperature oxidation process and in the ultrahigh-temperature activation annealing process have been proposed, they have been unable to reproduce each other’s experimental results.

Toshiba Electronic Devices & Storage Corporation has responded to this situation by developing a universal simulation model to predict the behaviors of interstitial carbon (Ci) and VC in SiC over a wide temperature range. By taking the capture and release of Ci due to defects in the SiC substrate into account, we have confirmed that the results calculated by this model are in good agreement with the results obtained experimentally.

HAYASHI Tsuneyuki / TODA Shuji / WADA Hiroshi / TAKAHASHI Yuichi

It is necessary for electronic equipment to provide reduced power consumption, increased power density, and improved power source efficiency toward the achievement of carbon neutrality.

The Toshiba Group has developed the TCK42xG series N-channel metal-oxide-semiconductor field-effect transistor (MOSFET) gate driver integrated circuits (ICs), which realize both compactness and low switching loss, focusing on load switching circuits for power management blocks. The TCK42xG series ensures low switching loss even in 100 W-class power supplies by incorporating our proprietary control mechanism for efficient MOSFET operation while reducing power consumption. In addition, with its ultracompact package, the TCK42xG series makes it possible for electronic equipment to be downsized.


In line with the changes taking place in energy policies accompanying the worldwide movement toward decarbonization to tackle the issue of climate change, the electrification of various systems for automobiles aimed at enhancing their environmental performance, as typified by the electrification of automobile power sources with the advent of electrified vehicles (xEVs), has recently been expanding in the automobile industry. The installation of electric motors, as key components supporting such electrification, has consequently been rapidly increasing. This, in turn, has given rise to the need for the electronic control units (ECUs) that drive such motors to be more compact and lightweight and to provide higher efficiency.

Under these circumstances, Toshiba Electronic Devices & Storage Corporation is developing the SmartMCD™ series integrated motor control drivers (MCDs) equipped with a built-in microprocessor fabricated employing an analog process using a fifth-generation platform for mixed-signal integrated circuits (ICs). The SmartMCD™ series makes it possible to efficiently drive electric motors while reducing the size and weight of the ECU board, with all of the necessary functions integrated in one chip.

UO Toyoaki / TAKAMIYA Shimon / FUJI Yoshihiko

The development of hybrid electric vehicles (HEVs) and electric vehicles (EVs) has recently been accelerating in line with the rapid global dissemination of these vehicles due to their lower greenhouse emissions compared with conventional gasoline-powered vehicles, as part of the movement toward the achievement of carbon neutrality. Digital isolators are one of the key electronic devices installed in HEVs and EVs, with the functions of transmitting signals while maintaining electrical insulation between high-voltage components, such as the inverter and battery control unit, and low-voltage components.

Toshiba Electronic Devices & Storage corporation has been engaged in the development of digital isolators that achieve high common-mode transient immunity (CMTI), which is crucial for the stable operation of inverters and battery control units, as well as enhanced insulation reliability.

ISHII Koji / SATO Takumi

The expansion of data center businesses, which are playing a key role in the storage and transmission of corporate and personal information due to the dissemination of Internet and cloud services, is driving demand for large-capacity nearline hard disk drives (HDDs). The larger capacity of such HDDs accompanying increases in recording density is expected to contribute to further progress of the information society. On the other hand, suppression of the rising power consumption of HDDs operating in data centers for prolonged periods is an important issue from the viewpoint of attaining carbon neutrality through the reduction of greenhouse gas emissions.

In response to customer demand for compliance with the Sustainable Development Goals (SDGs), particularly in the United States, Toshiba Electronic Devices & Storage Corporation has now developed the MG10 series 3.5-inch nearline HDDs with a storage capacity of 20 Tbytes. By incorporating technologies for optimizing their mechanical design, seek control design, and electrical design, the MG10 series HDDs achieve reduced power consumption per terabyte compared with predecessor products.


NABA Takayuki / HOTSUKI Naoto / HASEGAWA Koji

As part of the efforts being made toward achieving carbon neutrality in non-electric power sectors, the replacement of internal combustion engine (ICE) vehicles with electrified vehicles (xEVs), including electric vehicles (EVs), hybrid electric vehicles (HEVs), and fuel cell vehicles (FCVs), has recently been accelerating. There is consequently demand in the xEV market for the traction motor and inverter-equipped power control unit (PCU), which are commonly paired in such vehicles, to have higher output and reliability and to be more compact and lightweight.

Toshiba Materials Co., Ltd. is developing silicon nitride (Si3N4) ceramic products in response to these needs of the xEV market. In order to meet the increasing demand for the application of Si3N4 ceramic products, we are making efforts to develop Si3N4 bearing balls for traction motors offering high strength and high reliability, as well as Si3N4 insulated substrates capable of efficiently dissipating the heat of power semiconductors that are being widely adopted in PCUs. In parallel with this development work, we are also taking into consideration reduction of the environmental burden in the manufacturing processes for these products.

Feature Articles

ITO Kazuyuki / KIKUCHI Takuo / ODA Tatsuhiro / NISHIGUCHI Toshifumi

The Toshiba Group has developed a simulation technique to predict on-resistance (Ron) in trench type silicon (Si) power metal-oxide-semiconductor field-effect transistors (MOSFETs), based on the results of estimation of the membrane stresses inside the device obtained using the measured wafer warpage values and multiscale stress analysis.

We have applied this technique to a prototype device, and confirmed that it can predict the stress distribution of the Si substrate adjacent to the trench with a margin of error of within 10% and the Ron with a margin of error of within 3%. Furthermore, we have also calculated the stress distribution in each manufacturing process and clarified the processes in which stress control is important so as to realize a design with the appropriate Ron. This technique is expected to reduce backtracking in device development, leading to improvements in design efficiency.


The improvement of work efficiency at manufacturing sites is essential in order to enhance productivity, operating rates, and safety. On the other hand, methods to visually analyze business operations using images captured by handheld cameras often lead to decreased efficiency due to the considerable time required to manually check such images.

Toshiba Lighting & Technology Corporation has been supplying camera-equipped lighting fixtures that can be installed simply by replacing existing lighting fixtures. In addition, we have now developed a video analysis system that can analyze images captured by these camera-equipped lighting fixtures via a cloud system, applying a proprietary human detection artificial intelligence (AI) technology to process images from the ceiling viewpoint. This system enables users to efficiently promote various improvement activities at manufacturing sites, including safety management, analysis of workflow lines, and visualization of the time required for each operation, or so-called takt time.

MISHIMA Nao / SEKI Akihito

Toshiba Corporation has developed the world's first technology that can achieve absolute-scale three-dimensional (3D) measurements solely from images taken by a commercially available monocular camera with a zoom lens or with autofocus under different conditions.

Conventionally, images taken by a monocular camera can only be used for relative-scale 3D measurements. However, our newly developed technology makes it possible to provide absolute values by means of relative depth information obtained from images taken by a monocular camera from multiple viewpoints in combination with blur information contained in the captured images. As a result, this technology is expected to be applied to infrastructure inspections in order to facilitate measurements of part sizes for repairs from several images without requiring any prior size information or special devices and without the need for access to dangerous, difficult-to-inspect areas such as high places and inclines.

Frontiers of Research & Development

Data Interoperability Technology and Its Application to Data Ecosystem for Carbon Footprint of Products

*Company, product, and service names appearing in each paper include those that are trademarks or registered trademarks of their respective companies.