Prices Dropping for SiC Substrates for Power Devices

Jan 5, 2010 18:56 Tadashi Nezu, Nikkei Electronics

The pricing of silicon-carbide (SiC) substrates for power devices is decreasing while their qualities are improving.

One of the reasons is that the demand for them increased due to the increasing number of makers that deal with SiC power devices. Also, some substrate makers said that there is a price war triggered by the increasing number of manufacturers providing high-quality substrates.

A substrate maker said that, when bought in volume, the price of a 3-inch (75mm) aperture product was about ¥70,000 (approx US$763) in 2009, ¥30,000 lower than in 2008, though it varies depending on quality such as crystal fault density.

Several manufacturers are selling not only SiC substrates but also so-called "epitaxial substrates," which are SiC substrates laminated with an epitaxial layer. In Japan, Showa Denko KK is selling 4-inch epitaxial substrates. The company buys SiC substrates from other companies and coats them with an epitaxial layer.

Some epitaxial substrate makers said that the price of an epitaxial substrate with a 10μm-thick epitaxial layer is about twice as high as the price of a 3-inch substrate.

Several SiC substrates exhibited in Japan

Under those circumstances, some SiC substrates (4H type) and epitaxial substrates were exhibited at an exhibition that ran from Dec 17 to 18, 2009, along with an academic conference on semiconductor technologies in Japan.

Dow Corning Toray Co Ltd, which sells SiC substrates manufactured by Dow Corning Corp, claimed that the substrates are equivalent to the products of Cree Inc in terms of quality. Dow Corning Toray ensures a micropipe density of less than 3 units/cm² for its 3-inch 4H-type SiC substrate. And the actual micropipe density is about 0.2 units/cm², it said.

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