Japan’s Diamond Semiconductor Tech Nearing Commercialisation

Researchers at Japan's Saga University have created the world’s first power circuit using diamond semiconductors. (Saga University)

Diamond power semiconductors, with their exceptional capabilities, are on the verge of transforming various industries, from electric vehicles to power generation stations. Japan's significant advancements in diamond semiconductor technology are paving the way for their commercialisation, promising a future where these semiconductors could handle 50,000 times more electricity than silicon devices. As Japan leads the R&D efforts in this field, companies like Orbray and Power Diamond Systems are making remarkable progress in mass-producing diamond wafers and components. With the potential commercialisation of diamond semiconductors looming closer, the industry is poised for significant growth and innovation. 

How will the widespread adoption of diamond semiconductors impact the efficiency and performance of electric vehicles and power generation stations, what challenges need to be overcome for the successful commercialisation of diamond semiconductors, and how might the emergence of diamond semiconductors from Japan influence the global semiconductor market dynamics?

What challenges does diamond introduce in semiconductor design?

The dawn of electrification in modern society has ushered in a profound need for high-power electronics capable of handling increased loads with efficiency and sustainability. As our reliance on technology grows, so does the demand for materials that can support the next generation of power electronics.

Limitations of Traditional Silicon in High-Power Applications

Traditional silicon, while widely used, is increasingly reaching its limits in terms of efficiency, especially under high temperature and high voltage conditions. Consequently, attention has shifted towards materials like Silicon Carbide (SiC) and Gallium Nitride (GaN), which have demonstrated superior capabilities in these areas. However, the exploration does not end there; diamond, long valued for its aesthetic qualities, is now being examined for its potential as a new power semiconductor.

Diamond, a crystalline form of carbon, is renowned not just for its hardness and brilliance but also for its exceptional electrical and thermal properties. These characteristics make it a compelling candidate for use in power electronics.

Diamond's high thermal conductivity, for instance, enables it to efficiently dissipate heat, a critical factor in electronic devices where overheating can lead to failure. Its wide bandgap also means that diamond-based devices could operate at much higher voltages and temperatures than those made from silicon.

Despite these promising attributes, there are significant challenges that must be addressed before diamond can be widely adopted in semiconductor applications. One of the primary hurdles is its hardness.

Challenges in Fabricating Diamond-Based Devices

While diamond's hardness is a desirable trait in materials used for cutting and abrasion, it poses a distinct challenge in semiconductor manufacturing. The difficulty in cutting and shaping diamond makes the fabrication of diamond-based devices not only technically challenging but also costly.

Moreover, diamond's suitability for long-term device applications is hampered by its tendency to degrade over time. The stability of diamond under prolonged operational conditions remains a subject of research. This degradation can affect the performance and longevity of diamond-based electronic devices, potentially limiting their practical utility.

Another significant challenge is the relative novelty of diamond technology in the realm of power semiconductors. Unlike silicon, which has been at the centre of semiconductor technology for decades, diamond does not benefit from a mature technology ecosystem.

Emerging Technology Ecosystem for Diamond

Due to the new nature of diamond in semiconductors, researchers and engineers are, in many respects, starting from scratch. This lack of maturity means that much foundational work still needs to be done, from developing reliable manufacturing processes to understanding the long-term behaviour of diamond under various operational stresses.

Finally, the complex crystal structure of diamond complicates its manipulation during the production process. Manufacturing high-quality diamond semiconductors requires precise control over the material properties at the microscopic level, a task that involves sophisticated technology and significant financial investment. Thus, the cost of producing diamond devices remains a major barrier to its widespread adoption in the semiconductor industry.

Japanese researchers close to diamond semiconductors

In a remarkable leap forward for semiconductor technology, Japan is poised to make significant advancements in the field of diamond semiconductors, potentially leading to practical applications between 2025 and 2030. These developments are particularly notable because diamond semiconductors are known for their superior performance and ability to handle extreme conditions, which could transform various high-demand electronics sectors.

Diamond semiconductors are distinguished by their ability to operate at extremely high voltages and withstand temperatures that would challenge silicon. Their deployment in energy-demanding applications like electric vehicles and aerospace could mark a fundamental shift, reducing heat loss and extending device lifespans. Japan's advancements, particularly those coming from university-led R&D, signify a concentrated effort to lead in a competitive field where materials like silicon and gallium nitride currently dominate.

Japan's Role in Advanced Semiconductor Research

Saga University has been at the forefront of this innovation, having developed the world's first power device made from diamond semiconductors in 2023. This breakthrough was in collaboration with the Japan Aerospace Exploration Agency (JAXA), focusing on high-frequency components for space communication. The implications of this technology extend beyond terrestrial applications, potentially enhancing the reliability and performance of space exploration equipment.

The emphasis on high-frequency components for space applications demonstrates diamond's potential to improve signal integrity in extreme environments. JAXA's collaboration with Saga University on these projects highlights the appeal of diamond semiconductors, not only for their durability but for enabling more efficient power management in satellite and spacecraft systems, a critical factor in space exploration missions where reliability is paramount.

Moreover, Tokyo-based Orbray has developed mass-production technology for 2-inch diamond wafers and is progressing towards achieving 4-inch substrates. This scale-up is crucial for meeting the commercial demands of the electronics industry. Orbray's partnership with Anglo American plc and its collaboration with Mirai Technologies, supported by giants like Toyota and Denso, underscores the industry's commitment to integrating diamond semiconductors into mainstream applications, including onboard power devices for vehicles expected in the 2030s.

Scaling Production: Orbray's Push Towards 4-Inch Diamond Wafers

As Orbray scales its production capabilities, the industry watches closely to see if diamond wafers could outpace silicon and even SiC substrates in high-power devices. The commercialisation of 4-inch diamond substrates, once achieved, will address a crucial bottleneck in production, bringing the feasibility of widespread industrial applications closer and allowing Japan's semiconductor sector to set new standards globally.

The expansion doesn't stop there. Orbray plans to increase its production capabilities with a new facility in Akita Prefecture, eyeing an initial public offering by 2029. Concurrently, startups like Power Diamond Systems and Ookuma Diamond Device are enhancing the technology's application in power efficiency and environmental cleanup, respectively. Power Diamond Systems, a spinoff from Waseda University, is enhancing the current-carrying capacity of these devices, while Ookuma Diamond Device focuses on deploying them for nuclear waste removal at Fukushima Daiichi, demonstrating the material's resilience to high radiation.

Emerging Startups and Environmental Applications

Such resilience is not only pivotal for radiation-heavy applications but also enhances diamond's suitability for high-stress environments like nuclear power facilities. By applying these devices to nuclear waste removal, companies like Ookuma Diamond Device illustrate how diamond semiconductors could be transformative in both energy and environmental sectors, providing a durable alternative to conventional materials.

This burgeoning sector not only highlights the technical prowess and innovative spirit of Japanese research and development but also underscores a significant shift in materials science that could see diamond semiconductors becoming a cornerstone of future electronic and power devices. As these technologies mature, the potential for widespread adoption in everything from electric vehicles to aerospace and beyond could set a new standard in the industry, promising devices that are not only more robust but also more efficient than their silicon counterparts.

The Future of Diamond in Mainstream Applications

Incorporating diamond semiconductors into energy-intensive technologies could decrease overall power consumption while enhancing reliability, a combination that meets growing sustainability demands. As industries continue to prioritise eco-efficient technology, the move towards diamond-based solutions may further incentivise the shift to renewable energy sources, given diamond's superior thermal management and power capabilities.

As Japan leads in diamond semiconductor innovation, it underscores the global race to pioneer advanced materials that push the boundaries of electronic design. With the potential to meet both regulatory and environmental standards, diamond technology aligns with a sustainable future, setting Japan's R&D efforts apart in the international semiconductor landscape.

Could diamond replace other high-power semiconductor devices?

The advent of diamond semiconductor technology does not signal the obsolescence of GaN or SiC but rather marks a diversification of the materials available to engineers. Each material brings its unique set of properties to the table, enabling the design of more sophisticated and tailored electronic systems. As engineers and scientists, our task is not to seek a singular 'best' semiconductor material but to understand and exploit the distinct advantages of each material in harmony with others.

As diamond semiconductor technology becomes commercially viable, it will indeed open up new avenues for innovation. Engineers will be presented with fresh challenges and opportunities to push the boundaries of what is possible in electronics design. The exploration of diamond's potential in electronics is not just about adopting a new material but also about rethinking our approach to solving engineering problems and designing systems.

In conclusion

While the excitement around diamond semiconductors is certainly warranted, it is crucial to maintain a balanced perspective. The future of semiconductor technology will likely be characterised by a heterogeneous mix of materials, each selected for its ability to meet specific technical requirements in a cost-effective manner. The interplay between diamond, GaN, and SiC semiconductors will shape the next generation of electronic devices, driving innovation while addressing the practical realities of cost and application-specific needs. This nuanced approach will ensure the sustainable advancement of semiconductor technology, catering to an ever-expanding array of applications in the modern world.