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Novel Crystal Technology, Inc., working under NEDO’s “Key and Advanced Technology R&D through Cross Community Collaboration Program” for β-Ga2O3 wafers, power devices and modules, announced a new crystal growth method that eliminates precious-metal crucibles. The Drop-fed Growth (DG) process supplies raw-material melt as droplets, sharply reducing the use of iridium compared with the conventional Edge-defined Film-fed Growth (EFG) method and enabling β-Ga2O3 substrate manufacturing costs to fall to approximately one-tenth of current levels.
The company has demonstrated 95-mm-diameter β-Ga2O3 crystals grown without iridium crucibles. Using induction heating to raise the temperature inside the chamber, the crystal surface (seed crystal) is heated and locally melted by radiation through a shaped aperture that stabilizes the temperature profile and supports scale-up to larger diameters. Continuous droplet feeding of the melt onto the crystal surface, combined with downward pulling, enables steady growth without a precious-metal container.
Key benefits of the DG method include:
- Dramatic reduction in iridium usage by eliminating precious-metal crucibles
- Easier scale-up to large diameters via controlled surface heating and melting
- Continuous feed enabling production of long crystal boules
A 95-mm cylindrical crystal with a 50-mm grown section has been produced; n-type doping was introduced, as indicated by the crystal’s dark-blue coloration. Patent protection for the DG method is in place or underway in multiple jurisdictions, including Japan (Patent No. 7633637; application 2025-061932), the United States (US 11,725,299 B2; US 12,163,246 B2), Europe (EP 3 945 147 A1), and China (CN 114000188 A).
Looking ahead, Novel Crystal Technology plans to increase crystal diameter and quality using DG, targeting shipments of 150-mm (6-inch) β-Ga2O3 substrates in 2029 and 200-mm (8-inch) substrates in 2035. The company expects the method’s cost and scalability advantages to accelerate adoption of β-Ga2O3 for low-loss power devices across medium-voltage applications such as home appliances and EVs, and high-voltage systems including rail and grid infrastructure.
Original – Novel Crystal Technology
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Kyma Technologies in the US and Novel Crystal Technology (NCT) in Japan, both global leaders in Gallium Oxide (Ga2O3) technology, announced their strategic collaboration on development of Ga2O3 epiwafers for high voltage power electronics applications. This partnership aims to accelerate the development and commercialization of Ga2O3 devices for power electronics applications, including electric vehicles, renewable energy, aerospace, and industrial systems.
Gallium oxide offers significant advantages over traditional silicon and other wide-bandgap materials such as silicon carbide (SiC) and gallium nitride (GaN), including a higher breakdown electric field and the potential for lower production costs. However, a major industry bottleneck remains the limited availability of device-grade Ga2O3 epitaxial wafers with consistently low defects and scalable production methods.
By combining NCT’s expertise in producing high-quality bulk Ga2O3 substrates with Kyma’s advanced epitaxial growth capabilities, the two companies will develop processes to produce large area (150 mm diameter) epiwafers suitable for multi-kV level power devices.
Kyma and NCT have already worked together for many years (see HVPE-Based Gallium Oxide Epiwafer Development) and are now excited to announce that Kyma epi services on NCT substrates (up to 100 mm diameter) are available for sale to the broader research and development community. These epiwafers are expected to enable a new generation of power semiconductor devices that deliver higher efficiency and performance in demanding applications. For on-going power device development work, the technical teams at Kyma and NCT will be collaborating closely, including on specific customer requirements.
“Our partnership leverages the best of both companies’ technologies to push the boundaries of Ga2O3 epiwafer production,” said Heather Splawn, President & CEO of Kyma. “Novel Crystal Technology manufactures the best Ga2O3 substrates in the world, and we are thrilled that Kyma can now offer our unique epi growth on those substrates to our customers.”
Akito Kuramata, President & CEO of NCT, added, “We are excited to work with Kyma Technologies to further develop high-quality Ga2O3 epitaxial wafers. Together, we aim to accelerate the adoption of Ga2O3 devices worldwide, supporting critical industries and technology sectors.”
Original – Novel Crystal Technology
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Novel Crystal Technology (NCT), a global leader in Gallium Oxide (Ga2O3) technology, has successfully grown the first 6-inch Ga2O3 single crystal using the advanced Vertical Bridgman (VB) technique. This achievement marks a significant step forward in NCT’s efforts to deliver larger, high-quality semiconductor wafers for Ga2O3-based power devices.
The VB technique offers several advantages over NCT’s existing Edge-defined Film-fed Growth (EFG) method. By growing the crystal in a cylindrical shape, VB significantly reduces costs associated with substrate cutting. Additionally, it allows for production of substrates in various crystalline orientations, unrestricted by limitations imposed by crystal anisotropy.
Furthermore, the controlled thermal environment of VB growth leads to superior crystal quality with minimal defects, compared to EFG. Finally, dopant uniformity within the substrate is expected to improve, aligning with industry standards for other semiconductors like silicon.
NCT carried out a comparative evaluation between VB and EFG crystals with National Institute of Advanced Industrial Science and Technology (AIST) revealed a dramatic improvement in crystal quality. Synchrotron radiation X-ray topography analysis confirmed minimal defects in the VB-grown crystal, compared to the high density of defects observed in the EFG-grown crystal. This clearly demonstrates the superiority of the VB technique for producing high-quality Ga2O3 substrates.
Ga2O3 is a promising material for power electronics due to its ability to significantly reduce power loss compared to commonly used Silicon Carbide (SiC) in high-voltage applications, like electric vehicles and renewable energy systems. Its wide bandgap characteristics hold immense potential for energy conservation and CO2 emission reduction.
Established in 2015, NCT manufactures 2-inch and 100 mm gallium oxide (Ga2O3) substrates and epi-wafers for power devices. These are commercially available and used by universities, institutes, and power device companies worldwide. NCT currently supplies thousands of these substrates annually to support research and development efforts.
NCT is actively developing larger substrates such as 6-inch. Beyond substrates, NCT has a vision for broader Ga2O3 device production. They are already offering samples of their first Ga2O3 Schottky Barrier Diode, with qualification tests expected to be completed in September 2024.
The development of the Vertical Bridgman growth technique for Ga2O3 single crystals was initiated by Shinshu University, successfully achieving growth of 2-inch and 4-inch crystals. NCT acquired and extended their techniques to enable larger diameter crystal development. This research and development program was partially funded by the Adaptable and Seamless Technology Transfer Program through Target Driven R&D (A-STEP) of the Japan Science and Technology Agency (JST).
Original – Novel Crystal Technology
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Mitsubishi Electric Corporation announced that it has taken an equity position in Novel Crystal Technology, Inc., a Japanese company that develops and sells gallium-oxide wafers, a promising candidate for use in superior energy-saving power semiconductors that Mitsubishi Electric intends to develop at an accelerated pace in support of global decarbonization.
Novel Crystal Technology, one of the world’s first companies to develop, manufacture and sell gallium-oxide wafers for power semiconductors, and now a leading producer of these products, has manufacturing technology that Mitsubishi Electric will use in its production of gallium-oxide power semiconductors.
Mitsubishi Electric has been contributing to energy savings in power-electronic products by producing semiconductors made of silicon and silicon carbide (SiC). Recent advances have been achieved with SiC and gallium-nitride wafers, but gallium-oxide wafers are expected to help achieve even higher breakdown voltages and lower power dissipation.
Mitsubishi Electric now expects to accelerate its development of superior energy-saving gallium-oxide power semiconductors by combining its own expertise in the design and manufacture of low-energy-loss, highreliability power semiconductors with Novel Crystal Technology’s expertise in the production of gallium-oxide wafers.
Original – Mitsubishi Electric
