July 24, 2012 — Silicon carbide (SiC) is a niche material for semiconductor, power electronics, and light-emitting diode (LED) manufacturing. Yole Développement analyzed patents related to SiC growth and wafer manufacturing to glean trends in production, R&D, top companies, barriers to entry, and more.
Despite a cumulative raw wafers + epi wafers market that won’t exceed $80 million in 2012, SiC-related patents comprises over 1772 patent families with more than 350 companies involved in the material since 1928. 83% of patents cover a method; 17% of them claim an apparatus.
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| Figure. SiC crystal, wafer, and epiwafer patents distribution. SOURCE: Yole, July 2012. |
SiC growth
Since 1978, the main technique to grow bulk single crystals of SiC has been physical vapor transport (seeded sublimation method, PVT), covered in 36% of published patents, said Dr. Philippe Roussel, business unit manager, Compound Semiconductors, Power Electronics, LED & Photovoltaics, Yole Développement. PVT mostly deals with the hexagonal polytypenH SiC (n=2,4,6). Liquid phase epitaxy (LPE), an alternative SiC growth method developed in 1961, allows crystals to grow with low dislocation densities and at relatively low temperatures. LPE is an attractive SiC growth method for cubic polytype 3C SiC.
Chemical vapor deposition (CVD) almost exclusively dominates SiC epiwafer fab today, and is covered in about 37% of SiC-related patents. Molecular beam epitaxy (MBE) is only mentioned in 1% of patents. The polytype (hexagonal or cubic) is explicitly claimed in 15% of patents.
Numerous strategies to reduce crystal defects (micropipes, carrots, etc.) and make semi-insulating (SI) material are proposed in 23% and 10% of patents respectively.
Patent count vs revenues
About 350 patent applicants are involved in SiC crystal/epiwafer technology, pointed out Roussel, mainly located in Japan (72% of patents) and the US (12% of patents). The five major applicants based on their patents number are Denso, Sumitomo, Nippon Steel, Bridgestone and Toyota. They represent about 35% of studied patents. While Cree Inc. is the 6th major applicant for patents by volume, and the top US company on the list, US companies generate 75% of the SiC wafer business. Leaders include CREE, II-VI, and Dow Corning. Japan is only responsible for 5% of the revenues (at least before SiCrystal was acquired by Rohm). This trend of poor correlation between patent count and revenues is seen in Europe and the rest of Asia as well.
Only 3 Japanese companies are commercially active in SiC material: Showa Denko (epiwafer), Bridgestone (wafer) and Nippon Steel (wafer and epiwafer). China and Korea emerged as new players during the last 5 years, establishing Epiworld, TianYue, TYSTC, and Tankeblue in China and SKC in Korea. However, these companies’ market shares remain very low at the moment.
In the SiC substrate business, Cree holds about 50% market share on a worldwide basis, and has the best reputation in terms of quality, diameter and reproducibility. However, here again Cree does not own the widest patent portfolio.
The only SiC field where number of patents and business size are more balanced is SI SiC technology, where both Cree (vanadium-free) and II-VI (vanadium-doped) have extensively patented their respective developments.
Today’s SiC landscape
Today’s state-of-the-art SiC wafer is 6” diameter, no micropipe, with very low dislocation density. Only CREE seems able to offer such a product today. Barriers to entry and competition in the SiC arena are high, Yole points out.
Cree enjoys funding from the US Department of Defense (DOD), Department of Energy (DOE), Defense Advanced Research Projects Agency (DARPA), and the US Navy, improving its technology for LEDs and power electronics. Cree also likely benefits from cross-fertilization of technologies between LEDs and power electronics.
Virtually no SiC substrate companies are for sale today. Beyond the top 5 SiC substrate leaders, Yole does not see a clear positioning of companies who may want to participate in a sale or merger of their business.
New developments are being made around LPE at Toyota, Denso, and Sumitomo. 3C SiC (Cubic) may also disrupt the current PVT domination.
Report
“Patent analysis of SiC single crystal, wafer and epiwafer manufacturing” from Yole Développement presents the patent landscape for SiC single crystal and epiwafer over a total of 1772 patent families. Several key patents are selected based upon their interest regarding the particular technological issues related to the SiC development, as well as their possible blocking factor for new competing development. It puts in contrast the patent landscape with the current and expected market status, highlighting the most active companies, the patent transfer and the sleeping IP. The document also highlights and describes the key patents that could possibly block newcomers, for both crystal and epi-growth.
The analysis goes along with spreadsheets presenting the 1772 patents (Publication Number, Publication Date, Priority Date, Title, Abstract, Assignee(s) and Inventor(s), Legal Status) with direct link to the full patent text and pictures.
Report author: Philippe Roussel holds a PhD in Integrated Electronics Systems from the National Institute of Applied Sciences (INSA) in LYON. He leads the Compound Semiconductors, LED, Power Electronics and Photovoltaic department at Yole Développement.
Companies cited in this analysis: ABB, ACREO, AIST, Ascatron, ATMI, Bridgestone, C9 Corporation, Cabot, Cree, Crysband, Denso, Dow Corning, Ecotron, Epiworld, Fuji Electric, Fujimi, Fujitsu, Hitachi, Hoya, II-VI, Infineon, Kansai Electric Power, Kwansei Gakuin Univ., Mitsubishi, Mitsui, NASA, National Tsing Hua Univ., N-Crystals, NEC, NeoSemitech, Nippon Pillar Packing, Nippon Steel, NIRO, Nisshin Steel, Norstel, North Carolina Univ., Northrop Grumann, NovaSiC, Okmetic, Panasonic, POSCO, Rohm, Sanyo, SemiSouth, Sharp, Shikusuon, Shinetsu Chemical, Showa Denko, SiC Systems, SiCilab, SiCrystal, Siemens, Sumitomo Metal Industries, TankeBlue, Toshiba, Toyota, TyanYue, TYSTC, United Silicon Carbide, US Navy, Widetronix, etc.
Yole Développement is a group of companies providing market research, technology analysis, strategy consulting, media in addition to finance services. Learn more at www.yole.fr.