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