The fourth generation of semiconductors has arrived, can Ga2O3 replace SiC ?

Key Semiconductor Raw Materials under Export Controls
On August 1, 2023, the Ministry of Commerce and the General Administration of Customs of China officially implemented export controls on semiconductor raw materials gallium and germanium. There are various opinions in the industry regarding this move, and many people believe that it is in response to the Dutch ASML's upgraded control on the export of lithography machines. But in August 2022. The United States has included high-purity semiconductor material gallium oxide in its prohibited export control list to China. The Bureau of Industry and Security (BIS) of the US Department of Commerce has also announced the inclusion of fourth generation semiconductor materials such as gallium oxide and diamond, which can withstand high temperatures and voltages, as well as ECAD software specifically designed for chips at 3nm and below, into new export controls.
    At that time, there were not many people paying attention to this export control, and it was not until a year later that China included gallium in the export control list that the industry began to pay attention to the important material of fourth generation semiconductors - gallium oxide. Gallium and germanium are key raw materials in the semiconductor industry, and their applications cover the manufacturing of first to fourth generation semiconductors. Today, with Moore's Law facing a bottleneck, semiconductor materials with larger bandgap widths, such as diamond, gallium oxide, AlN, and BN, have the potential to become the driving force for the next generation of information technology due to their excellent physical properties.
    For China, it is a critical period for the development of semiconductors, and various sanctions from the United States have made the research of key revolutionary materials such as gallium oxide a key breakthrough constraint. Despite the numerous challenges, if we can succeed in this semiconductor technology revolution, China will have the potential to leap from a manufacturing powerhouse to a manufacturing powerhouse, achieving a truly unprecedented transformation in a century. This is not only a major test of China's technological strength, but also an important opportunity to showcase China's ability to face global technological challenges.

Advantages beyond silicon carbide and gallium oxide
Gallium oxide, a fourth generation semiconductor material, has advantages such as large bandgap width (4.8 eV), high critical breakdown field strength (8MV/cm), and good conduction characteristics. Gallium oxide has five confirmed crystal forms, among which the most stable is β- Ga2O3. Its bandgap width is 4.8-4.9 eV, and the breakdown field strength is as high as 8 MV/cm. Its conduction resistance is much lower than that of SiC and GaN, greatly reducing the conduction loss of the device. Its characteristic parameter, Baliga Premium (BFOM), is as high as 3400, approximately 10 times that of SiC and 4 times that of GaN.

Compared to silicon carbide and gallium nitride, the growth process of gallium oxide can be achieved using the liquid melt method at atmospheric pressure, which results in high quality, high yield, and low cost. Due to their own characteristics, silicon carbide and gallium nitride can only be produced by gas-phase method, which requires maintaining a high-temperature production environment and consuming a large amount of energy. This means that gallium oxide will have a cost advantage in production and manufacturing, and is suitable for domestic manufacturers to quickly increase production capacity.

In comparison with silicon carbide, gallium oxide surpasses silicon carbide in almost all performance parameters. Especially with its large bandgap width and high breakdown field strength, it has significant advantages in high-power and high-frequency applications

Specific Applications and Market Potential of Gallium Oxide
The development prospects of gallium oxide are increasingly prominent, and the market is currently mainly monopolized by two giants in Japan, Novell Crystal Technology (NCT) and Flosfia. NCT has been investing in the research and development of gallium oxide since 2012, successfully breaking through multiple key technologies, including 2-inch gallium oxide crystal and epitaxial technology, as well as mass production of gallium oxide materials. Its efficiency and high performance have been widely recognized in the industry. It successfully mass-produced 4-inch gallium oxide wafers in 2021 and has started supplying customer wafers, once again keeping Japan ahead in the third-generation compound semiconductor competition.
According to NCT's prediction, the market for gallium oxide wafers will grow rapidly in the next decade and expand to approximately RMB 3.02 billion by 2030. FLOSFIA predicts that by 2025, the market size of gallium oxide power devices will begin to surpass that of gallium nitride, reaching 1.542 billion US dollars (approximately 10 billion RMB) by 2030, accounting for 40% of silicon carbide and 1.56 times that of gallium nitride. According to the prediction of Fuji Economy, the market size of gallium oxide power components will reach 154.2 billion yen (approximately 9.276 billion yuan) by 2030, surpassing the market size of gallium nitride power components. This trend reflects the importance and future potential of gallium oxide in power electronic devices.

Gallium oxide has significant advantages in certain specific application fields. In the field of power electronics, gallium oxide power devices partially overlap with gallium nitride and silicon carbide. In the military field, they are mainly used in power control systems such as high-power electromagnetic guns, tanks, fighter jets, and ships, as well as radiation resistant and high-temperature resistant aerospace power supplies. The civilian sector is mainly applied in fields such as power grids, electric traction, photovoltaics, electric vehicles, household appliances, medical equipment, and consumer electronics.

     The new energy vehicle market also provides a huge application scenario for gallium oxide. However, in China, the power devices at the vehicle level have always been weak, and there is currently no SiC MOS IDM at the vehicle level. Although several Fabless companies that contract with XFab can quickly have comprehensive SBD and MOS specifications to market, and sales and financing progress is relatively smooth, in the future, they still need to build their own FAB to master production capacity and develop unique processes, in order to generate differentiated competitive advantages.
Charging stations are very cost sensitive, which provides an opportunity for gallium oxide. If
    If gallium oxide can meet or even exceed performance requirements while gaining market recognition with cost advantages, there is a great possibility of its application in this field.
In the RF device market, the market capacity of gallium oxide can refer to the market of silicon carbide epitaxial gallium nitride devices. The core of new energy vehicles is the inverter, which has very high requirements for device specifications. Currently, companies such as Italy Semiconductor, Hitachi, Ansemy, and Rohm are able to mass produce and supply automotive grade SiC MOSFETs. It is expected that by 2026, this number will increase to $2.222 billion (approximately 15 billion RMB), indicating that gallium oxide has broad application prospects and market potential in the RF device market.
     Another important application in the field of power electronics is 48V batteries. With the widespread use of lithium batteries, a higher voltage system can be used to replace the 12V voltage system of lead batteries, achieving the goals of high efficiency, weight reduction, and energy conservation. These lithium battery systems will widely use 48V voltage, and for electronic power systems, high-efficiency 48V → 12V/5V conversion is required. Taking the two wheeled electric vehicle market as an example, according to data from 2020, the overall production of electric two wheeled vehicles in China was 48.34 million units, a year-on-year increase of 27.2%, and the penetration rate of lithium batteries exceeded 16%. Faced with such a market, 100V high-voltage high current devices such as gallium oxide, GaN, and silicon based SG-MOS devices are targeting this application and making efforts.
     In the industrial field, it has several major opportunities and advantages, including unipolar replacement of bipolar, higher energy efficiency, ease of mass production, and reliability requirements. These characteristics make gallium oxide potentially play an important role in future power applications. In the long run, gallium oxide power devices are expected to play a role in the 650V/1200V/1700V/3300V market, and are expected to fully penetrate the automotive and electrical equipment fields from 2025 to 2030. In the short term, gallium oxide power devices will first appear in fields such as consumer electronics, home appliances, and highly reliable and high-performance industrial power supplies. These characteristics may lead to competition between materials such as silicon (Si), silicon carbide (SiC), and gallium nitride (GaN).

     The author believes that the focus of competition for gallium oxide in the next few years will be on the conventional use of 650V devices on the 400V platform. The competition in this field will involve multiple factors such as switching frequency, energy loss, chip cost, system cost, and reliability. However, with the advancement of technology, the platform may be upgraded to 800V, which will require the use of 1200V or 1700V devices, which is already an advantage area for SiC and Ga2O3. In this competition, startups have the opportunity to establish scenario awareness, vehicle regulation system, and customer mentality through in-depth communication with customers, laying a solid foundation for the application of inverters to automotive enterprise customers.
    Overall, gallium oxide has great potential in the field of power devices and can compete with materials such as SiC and GaN in multiple fields to meet the needs of high-performance applications such as high efficiency, low energy consumption, high frequency, and high temperature. However, the penetration of new materials in applications such as inverters and chargers takes time and requires continuous development of suitable specifications for specific applications, gradually promoting them to the market.