Japanese power semiconductors take another step forward

Japan has always played a leading role in the field of semiconductor materials. In terms of new power semiconductor material oxide, Japan is also expected to set off a new wave of trends. According to the market report of Japan's Yano Research Institute, gallium oxide wafer substrates will partially replace SiC and GaN materials in 2025, and the market size will reach 260 billion yen; and according to the global market forecast of Wide Gap power semiconductor components released by market research company Fuji Keizai on June 5, 2019, the market size of gallium oxide power components will reach 154.2 billion yen in 2030, and the entire gallium oxide market capacity will show a blowout and leapfrog development with the development of power electronics.

What is gallium oxide? First of all, gallium oxide (Ga 2 O 3 ) is not a new material. In 1952, scientists discovered its five variants α, β, γ, δ and ε, among which β-gallium oxide is more stable. It has a history of nearly 70 years. In the semiconductor field, it was mainly used for LEDs (light-emitting diodes) and substrates in the early days, and was not used as a power semiconductor. Now due to its ultra-wide band gap advantage, it is regarded as a newer generation of materials for power semiconductors. Gallium oxide has an ultra-large band gap of 4.8eV, while the band gaps of SiC and GaN are 3.3eV, and silicon is only 1.1eV. From the figure below, it can be seen that gallium oxide has absolute advantages in critical electric field strength and bandgap width. In addition to the characteristic of high bandwidth, the main reason for using gallium oxide as a semiconductor material is its low production cost.

Comparison of the properties of GaAs, GaN, GaO, Silicon, and SiC

(Source: IEEE)

In the research of gallium oxide, Japan is in the leading position in the world in the research and development of substrates, epitaxy and devices. As early as 2012, Japan first achieved a breakthrough in 2-inch gallium oxide materials. It is worth mentioning that it is not large and medium-sized power semiconductor companies that develop gallium oxide power components, but some start-ups. In recent years, with the strong support of the Japanese government and relying on major Japanese universities, many manufacturers in the field of gallium oxide have been separated and have made many breakthroughs.

Novel Crystal Technology (NCT) is a developer, manufacturer and supplier of homoepitaxial wafers of gallium oxide. Its main focus is β-Ga 2 O 3. NCT's gallium oxide technology is based on Tamura Corporation of Japan, the National Institute of Information and Communications Technology (NICT) of Japan and Tokyo University of Agriculture and Technology. On June 16, 2021, NCT successfully mass-produced 100mm (4-inch) "gallium oxide" wafers for the first time in the world. This is the first time that gallium oxide wafers have been mass-produced worldwide. In March 2022, NCT successfully epitaxially deposited gallium oxide on 6-inch wafers using the HVPE method. NCT said that this move will hopefully reduce costs to one-third of SiC. According to NCT's forecast, the market for gallium oxide epitaxial wafers will expand to approximately 59 billion yen by 2030.

β-Ga 2 O 3 thin film formed on a 6-inch test wafer

Development of a 6-inch single-wafer HVPE system for β- Ga2O3 epitaxial deposition

On July 25, Japanese media reported that Japanese manufacturer FLOSFIA is expected to start mass production of SBD (Schottky barrier diode) in 2022. FLOSFIA was spun off from Kyoto University in 2011 and specializes in the research and development and commercialization of gallium oxide (α-Ga 2 O 3 ) thin films formed by mist chemical vapor deposition (CVD). DENSO also invested in its 2017 Series C financing.

FLOSFIA exhibited an evaluation board of "Gallium Oxide SBD", an SBD using gallium oxide, at "TECHNO-FRONTIER 2022". The maximum rated voltage of the gallium oxide SBD is 600V and the forward current (I f ) is 10A. FLOSFIA focuses on the development of α-Ga 2 O 3 , and the company believes that the α type is the power device closest to practical use. FLOSFIA has a unique film-forming technology "mist drying method" that can produce stable α-Ga 2 O 3 with excellent characteristics . α-Ga 2 O 3 has a wide bandgap of 5.3eV and a high breakdown field strength, which can better withstand high-voltage applications.

Another startup from Tohoku University, C&A, and the research and development team of Tohoku University professor Akira Yoshikawa have developed a device to produce gallium oxide crystals by directly heating the raw materials, and have produced crystals up to about 5 cm in size. The new technology puts the raw materials into a copper container cooled by water and uses electromagnetic waves with a frequency about 100 times that of the previous method to melt the raw materials. Because expensive containers are not required, the new method can produce gallium oxide crystals at about 1/100 of the current cost. The company strives to produce crystals with a diameter of more than 15 cm within 2 years.

Image source: Nikkei Chinese website

It can be seen that many Japanese companies have made great achievements. Once gallium oxide-based power semiconductors are commercialized, they will be applicable to many fields due to their advantages in cost and performance. When this trend comes, Japanese companies will surely be the first to profit.

Although Japanese companies are considered to be in a slump in the entire semiconductor field, Japan has a strong presence in the entire power semiconductor field. According to Omdia data, half of the top ten power chip companies in the world are Japanese companies. Mitsubishi Electric (4th), Fuji Electric (5th), Toshiba (6th), Renesas (9th), ROHM (10th). These five companies together account for more than 20% of the global power chip market share.

Mitsubishi Electric Corporation was founded on January 15, 1921, and in 1997 it pioneered the mass production of power semiconductor modules for hybrid vehicles. Mitsubishi Electric is the king of IGBTs in Japan. In November 2021, Mitsubishi Electric set a goal for its power device business to achieve sales of more than 240 billion yen and an operating profit margin of more than 10% by 2025. To achieve its goals, Mitsubishi Electric announced that it will invest 130 billion yen in its power semiconductor business over the next five years. The company plans to build a new 12-inch (300 mm) wafer production line at the Fukuyama Plant (Fukuyama City, Hiroshima Prefecture), and plans to double its production capacity by 2025 compared to 2020.

Fuji Electric was founded in 1923 as a capital and technology alliance between Japan's Furukawa Electric Co., Ltd. and Germany's Siemens AG. Fuji Electric began producing the first generation of IGBTs in 1988. In 2010, it began developing SiC power semiconductor modules. The company's mid- to long-term goal is to invest 90% of its capital and 80% of its research and development (R&D) in the power electronics system and power semiconductor businesses, of which 120 billion yen of power semiconductor factory equipment investment accounts for about half of the total investment.

Fuji Electric equipment investment list

Toshiba was formed in 1939 by the merger of Shibaura Works (founded in 1875) and Tokyo Electric (founded in 1890), formerly known as Tokyo Shibaura Electric Co., Ltd. The company name was officially changed to Toshiba Corporation in 1978. In terms of power semiconductor business, in April 2022, Toshiba stated that it would build a new 300mm wafer manufacturing plant for the production of power semiconductors at Kaga Toshiba Electronics Corporation, its main discrete semiconductor production base in Ishikawa Prefecture. It will be built in two phases, optimizing the investment rhythm according to market trends. The first phase is scheduled to start production in fiscal 2024. When the first phase reaches full capacity, the estimated production capacity will be 2.5 times that of fiscal 2021.

Renesas Renesas is the result of the merger of the semiconductor divisions of Hitachi, Mitsubishi, and NEC Electronics. On May 17, 2022, Renesas invested 90 billion yen to restart the Kofu plant as a 300mm wafer plant dedicated to power semiconductors. The plant was closed in October 2014 and was previously a 150mm and 200mm wafer manufacturing line. Once the Kofu plant achieves mass production, Renesas' total production capacity of power semiconductors such as IGBTs will double.

Rohm was founded in Kyoto in 1958 as a small electronic component manufacturer. Production expanded to include transistors and diodes in 1967, and ICs and other semiconductor products were added to the product lineup in 1969. Rohm is Japan's largest producer of SiC power semiconductors and produces the SiC wafers used to manufacture them through its German subsidiary SiCrystal. Rohm has more than 10% of the global SiC power semiconductor market and 15-20% of the SiC wafer market.

Japan also has material manufacturers further upstream, such as Showa Denko, which produces SiC epitaxial wafers, and Sumitomo Metal Mining, which produces SiC wafers.

Showa Denko has the largest market share of SiC epitaxial wafers in the world. The company's SiC business has successfully expanded from epitaxy to substrates, with the goal of improving the quality of SiC epitaxial wafers, expanding business scale, and enhancing overall competitiveness. According to news in March this year, Showa Denko has successfully mass-produced 6-inch SiC single crystal substrates, which will be used to produce SiC epitaxial wafers.

In January 2022, according to Nikkei, Sumitomo Metal Mining began mass production of SiC wafers. It is reported that Sumitomo Mining has developed related technology to attach a layer of "single crystal SiC" that can reduce power generation losses to the bottom "polycrystalline SiC" which is cheaper due to irregular crystallization, thereby making a wafer. Cheap materials can be used at the same time, and the price is about 10% to 20% lower than traditional products with the same performance. Sumitomo Mining is considering developing 8-inch products that can efficiently mass-produce power semiconductors and building production bases overseas. Strive to use the new wafers for home appliances first, and it is expected to be equipped in electric vehicles after 2025.

In addition to these companies, Japan also has many companies involved in power semiconductors, including Denso, Fujitsu Semiconductor, Hitachi, Kyocera, New Nippon Radio, Fintech Semiconductor, Sanken Electric, Sansha Electric Manufacturing, Seiko NPC, Shindengen Electric Manufacturing, and Toyota Industries.

However, it can also be seen that the scale of Japanese power semiconductor manufacturers is relatively small. The market share of Infineon, the world's largest power chip manufacturer, is 21%, which is the sum of the market share of five Japanese manufacturers. In order to maintain their position in the power semiconductor field, Japanese power semiconductor manufacturers have also begun to make major strategic adjustments.

Aiming at the booming market of pure electric vehicles, Japanese power semiconductor companies have begun to increase production of SiC, a third-generation semiconductor material with higher performance. Whether Japanese companies can attract powerful customers in the field of new-generation SiC power semiconductors will be the key to expanding their market share in the future.

Although Rohm ranks 10th in the overall power semiconductor market share, in terms of SiC alone, Rohm accounts for 14% of the world, ranking around 4th. Rohm plans to increase its global share of SiC power semiconductors to 30% in 2025 and expand its production capacity by more than 6 times, so Rohm's investment in SiC is as high as 170 billion yen. On June 8, 2022, Rohm held an opening ceremony for a new SiC power semiconductor plant in Chikugo City, Fukuoka Prefecture. This is the first time that a domestic semiconductor manufacturer in Japan has built a dedicated SiC power semiconductor plant. The integrated development of the production of SiC wafers, SiC devices, etc. will provide Rohm with more competitiveness in the SiC field.

Toshiba Devices & Storage, a semiconductor business subsidiary of Toshiba, plans to increase the production of SiC power semiconductors at the Himeji Semiconductor Factory in Taishi Town, Hyogo Prefecture, Japan, to more than three times the 2020 level in 2023, and to increase it tenfold as soon as possible. Strive to obtain more than 10% of the global share by 2030 at the latest Toshiba plans to increase the production of SiC power semiconductors by more than three times by 2024 and ten times by 2026.

Fuji Electric of Japan has increased its investment in the field of power semiconductors and built a SiC power semiconductor production line at its Tsugaru plant. Earlier this year, Fuji Electric said it would increase SiC production capacity at its power semiconductor production base, Fuji Electric Tsugaru Semiconductor. It is also considering bringing the production of SiC products forward by half a year to a year compared to the original plan (2025).

In August 20201, Showa Denko announced that it would raise approximately 110 billion yen in funds through public offerings and third-party quota increases, of which approximately 70 billion yen would be used to expand the production capacity of semiconductor materials such as SiC wafers. Currently, Japanese manufacturers such as Rohm and Toshiba have signed multi-year long-term supply contracts with it.

Mitsubishi Electric is also strengthening its SiC layout. In addition to applying a unique manufacturing process to trench MOSFETs to further improve performance and productivity, it is also considering manufacturing 8-inch SiC wafers.

According to data from the Japanese research agency Yano Research Institute, it is estimated that before 2025, as 6-inch SiC wafers are truly introduced into mass production and power semiconductor manufacturers advance in mass production technology, the cost of SiC power semiconductors will drop, driving the use of SiC power modules from high-end electric vehicles to some mid-range electric vehicles. In addition, after 2026, more car manufacturers will consider using SiC power modules in their newly launched electric vehicles. Therefore, it is estimated that the automotive SiC-PM market will truly enter a period of expansion from 2026, and the SiC power module market size is expected to exceed the Si power module market in 2030.

A few years ago, when SiC/GaN first emerged, the industry had mixed opinions on its industrialization. However, now, with the efforts of all sectors of the industry, more and more cars are beginning to introduce SiC, and fast charging has also achieved good performance due to the use of GaN. I believe that the commercialization of the new power semiconductor material gallium oxide (Ga 2 O 3 ) can also be expected, because it is very important that they are all products of the low-carbon economy.

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