An article for SEMICONDUCTOR ENGINEERING written i collaboration with Ezgi Dogmus, team lead analyst in Yole Intelligence, part of Yole Group’s Power & Wireless Division – Power and RF will drive volume, with many new uses underway.
A huge GaN market is opening up, driven by consumer devices and the need for greater energy efficiency across many applications. Suppliers are ready, but to fully compete with SiC in high-voltage automotive applications will require further technological developments in power GaN (gallium nitride).Still, the 2020s mark a very high-growth phase for GaN markets. Revenues in the power GaN market are growing at a 59% CAGR (2021 to 2027), on target for hitting $2 billion in five years (per Yole Group’s Power GaN 2022 report).
Leading the high-growth path is the consumer segment, which for power GaN alone should flirt with the billion-dollar mark by 2027, followed by datacom and automotive/mobility. The RF GaN market is no slouch, either. Over a similar period, that market should reach $2.5 billion, with nothing but high growth beyond, predicts Yole.
That means a lot of pressure on IDMs and fabs — and on their equipment suppliers. “Those are massive markets,” notes Victor Veliadis, executive director and CTO of the PowerAmerica consortium. “But that mass market pressure is going to put a lot of financial pressure on. So they’re going to have pressure to have higher throughput, higher yield, bigger wafers.”
Fortunately, GaN manufacturing can largely be done by the same equipment used for silicon CMOS. The exceptions are the critical epitaxy steps at the onset, which will become even more critical as power GaN reaches for ever higher voltages. However, beyond epi, leading equipment suppliers are working ever more closely with their customers to respond to burgeoning demand.
GaN starts with epi. What varies is the kind of wafers on which the epitaxy is grown. Those starting wafers can be silicon, silicon carbide, sapphire, or even bulk GaN. It depends on the design choices and the target applications. But whatever the starting substrate, GaN epitaxy is complex. Because the crystalline structure of the starting wafers is different from the ultimate top GaN layer (unless, of course, you’re starting with bulk GaN wafers, which are just a few inches in diameter, which makes them less attractive), buffer layers are needed to make the crystalline transition.
GaN epi is applied by metal-organic CVD (MOCVD). “When looking at GaN HEMT manufacturing, MOCVD tools are masterpieces. For that, there are several providers, namely Aixtron, Veeco, and Taiyo Nippon Sanso,” noted Taha Ayari, technology and market analyst in Yole’s Compound Semiconductor and Emerging Substrates group. “These tools need to satisfy several criteria such as throughput, thickness and composition uniformity, reproducibility, and yield control. Etching tools are also important since clean sidewalls and smooth surfaces are needed. Key suppliers of etching tools are SPTS (a KLA company), Lam Research, and Oxford Instruments, amongst many others. Generally speaking, equipment suppliers need to work hand-in-hand with their clients to better understand the requirements of the GaN manufacturing process.”
The explosion of the power GaN market is driven by adoption in the consumer phone charger market, where mass production and higher volumes with lower prices are required. This implies transitioning to larger wafer sizes from the mainstream 6-inch silicon substrates. Today, some players already have 200mm (8-inch) GaN-on-Si fabs (Innoscience and X-Fab), or they are moving to 200mm (Infineon, STMicroelectronics, Nexperia, BelGaN, and TSMC) in the coming years, said Ezgi Dogmus, team lead analyst in Yole’s Power & Wireless Division.
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Source: Semiconductor Engineering.