Among other ultra-wide band gap materials, such as gallium nitride and silicon carbide, gallium oxide has many advantages. However, its production is much more challenging.
A four-inch crucible requires about 11 pounds of iridium; since the price of iridium is three times that of gold, this increases production costs. It also raises concerns about intellectual property in China since Japan and the US have used the method.Last year, researchers at the State Key Laboratory of Silicon Materials at Zhejiang University made two-inch gallium oxide wafers. This year, they have improved their approach and made four-inch wafers.
The team has spun off a company that holds the patents for these improved methods and is currently working on using a temperature gradient to increase the size of the crystals produced. Last year, the US Commerce Department imposed an export ban on gallium oxide to China, citing concerns about national security since they can also be used for military purposes. The ban aimed to prevent China from gaining experience in next-generation semiconductors, where gallium oxide alone is expected to be a $1.5 billion opportunity by the end of the decade.