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Vendor View - GTAT's Pure Play On Silicon Carbide Crystal

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Figure 1 A portion of GTAT's production area at its Hudson, New Hampshire facility

Company Rapidly Increasing the Supply of SiC

Everywhere you look, the ‘electrification of everything' is happening. Reliance on fossil fuels is, little by little, ebbing. While the shift is not a swift one, there is widespread agreement that ‘clean' power is the direction the world is headed. Worldwide, more than 25 countries have announced a phase-out of internal combustion vehicles in the next few years as they invest in clean technology systems. In the United States, California, Massachusetts, and New Jersey are heading in the same direction.

It is against this backdrop that foundational developments are taking place at GT Advanced Technologies (GTAT). One of these is the emergence of advanced semiconductor materials and devices that can handle the kind of power needed to efficiently drive applications ranging from electric vehicles to massive data centers. Semiconductors have traditionally been built upon silicon wafers. Silicon chips make sense for mobile phones, watches, and televisions where cost and performance factors lend themselves to that material. But the electrification of cars, trucks, trains and other ‘power electronics' applications (where voltages and currents exceed what silicon can efficiently handle) point to advanced semiconductor materials such as silicon carbide (SiC). First, it is extremely efficient with minimal losses and high switching speeds (transitioning from an ‘ON' state to ‘OFF'). Second, chips made from SiC run at higher temperatures that enable minimal cooling requirements. Third, devices made from SiC can be smaller and therefore lighter. Using the electric vehicle as an example, SiC provides smaller and lighter powertrains, faster charging, and better range. Complementary to this, charging stations based on SiC technology will quicken the process to fully charge a vehicle.

GTAT's role here is to make the SiC crystal that others downstream use to make wafers and devices. This is an important supply chain distinction because what the market demands is a rapidly growing supply of SiC crystal at affordable prices. “That is what the market is signaling,” says GTAT President and CEO Greg Knight. “There are many superb companies around the world that are very adept at wafering and device fabrication, and the goal is to put our CrystX® SiC at their doorstep at competitive prices and in high volume.” Over the past year, GTAT has signed long-term supply agreements with three of the largest global makers of wafers and devices.

Producing SiC is much more involved and challenging than making silicon crystal, and the material is not defect-free. While the technical benefits of SiC are well understood, producing the crystal in volume and at a cost and quality level that markets demand is challenging. “Our business model gives every company wishing to get into SiC a way to immediately do so,” said Knight. “They don't need to invest in the capital and complex knowhow, because we've already done that.” The result is a much more rapid ‘path forward' for SiC across growing markets that need the material. Wafer producers with strength in silicon can now offer SiC, which is a valuable portfolio position to have as applications transition from one material to the other.




Figure 2 As a 'pure play' producer of silicon carbide, GTAT is able to provide 'pucks' to downstream makers of wafers and semiconductors.

GTAT's heritage as a crystal-growth equipment and technology provider puts it at a distinct advantage as demand accelerates for affordable SiC wafers. “There is a tremendous amount of knowhow we've brought to bear here,” said Knight. “We design equipment to enable the most robust and repeatable crystal growth process while minimizing capex and cost of ownership. We excel at building crystal-growth equipment and can scale very rapidly, and we have a strong and fundamental understanding of the science needed to drive material quality to the highest levels.”

Indeed, a mere 18 months after beginning production of CrystX® SiC, GTAT has achieved quality levels leading to long-term supply agreements with Global Wafers, ON Semiconductor and Infineon. “These are the companies that are highly invested in making the ‘electrification of everything' a reality, and they are coming to us for their crystal material,” Knight said. GTAT produces its CrystX® SiC at 150mm diameter now and is driving toward 200mm to achieve a 1.8x increase in the number of devices that the larger surface area makes possible. GTAT's quality levels are always being driven higher, which is the major focus point for the Company. One of the major benefits of GTATs overall process is the ability to deliver very precise resistivity values for its SiC. While the standard industry range of 19-22 Ω-cm for SiC is very attainable, GTAT meets customer specifications with the tightest distribution across the crystal.