GTAT meeting rapidly growing demand for SIC
According to Precedence Research in a report from January 8, 2021, the global electric vehicle market is expected to grow by more than 40% by 2027. What it says, among other things, is that the supply chain for chips and modules powering these vehicles needs to evolve immediately. One of the obvious shifts will be moving away from traditional devices made from silicon and toward devices made from compound semiconductor materials such as silicon carbide (SiC). At higher voltages needed for EV’s, the performance properties of SiC far outpace those of silicon, but the supply chain for SiC is not nearly as mature. The global EV market needs SiC to catch up…and quickly.
Integrated Device Manufacturers (IDMs), already well-versed in silicon, needed a pathway to produce SiC devices and modules for rapidly accelerating EV demand. But SiC is more complex because it comes from a crystal that is extremely difficult to grow, and that presented a bottleneck. It is against this backdrop that GTAT (www.gtat.com) began forging a business model in 2017 to become a ‘pure-play’ producer of wafering-ready SiC. The Company’s focus on growing SiC bulk crystal and staying away from wafering and device-making is an important distinction. “We have a core competency, and that’s crystal growth,” says GTAT President and CEO Greg Knight. “There are tremendously talented companies around the world that know how to make wafers and devices, but what they don’t necessarily have is a way to grow the SiC crystal. They need the material, and lots of it.”
GTAT’s heritage as a producer of crystal growth equipment means that it can ‘scale up’ capacity very rapidly. The knowhow needed to design and build crystal-growth furnaces is the essence of GTAT’s DNA. “We are able to bring SiC capacity to market faster than anyone,” said Knight. Indeed, the Company has hit milestones extraordinarily rapidly. “We made our CrystX® silicon carbide n-type material available to customers in 2018, less than a year after opening our facility,” said Knight. A year after that GTAT achieved ISO 9001:2015 certification and signed the first of several long-term supply agreements with key customers for 150mm diameter boules.
Fundamentally, SiC is not a defect-free material and is challenging to make at the high quality levels customers demand. That is why most of the companies invested in making SiC wafers and devices do not have the experience to also make the crystal material itself. The equipment used to make silicon cannot be used for SiC, and the capex (and time) required to develop in-house SiC growth is significant. “We understood this early-on,” said Knight. “We knew that SiC was going to become the base material for semiconductors used in growing applications such as EV.”
The fact that SiC is not defect-free means that GTAT has spent considerable resources to drive those defect rates down. The chart shows GTAT’s very aggressive trend since introducing its CrystX® silicon carbide material.
GTAT is driving defect rates down significantly and rapidly.
Specifically, Etch Pit Density (EPD) and Basal Plane Dislocations (BPD) are critical quality metrics for SiC. GTAT has made significant progress driving down BPD’s to less than 1,000 per cm2 and is set to reduce this by another 50% in the near term. Much of GTAT’s focus has been on reducing defects through continuous improvement. “This is what our customers demand, and we deliver,” said Knight. “We have a longstanding heritage in building the equipment we now use ourselves, and we couple that with a high level of process excellence.” GTAT’s inherently stable production process enables all its high-quality material to be made to this standard, which is available under a single product grade.
While continuous improvement is a function of GTAT’s increased cycles of learning and optimization, R&D efforts allow the company to push forward on 200mm diameter SiC as well as semi-insulating (SI) SiC for RF applications. Both product launches are expected in late 2021 or early 2022. To support existing 150mm demand while forging ahead with 200mm and SI, GTAT is currently growing production capacity by 60% on top of what exists today. With multiple supply agreements in place, the ability to ramp up quickly puts GTAT in a perfect position. “Rapidly growing markets like EV require a very nimble supply chain, and we’re able to respond,” said Knight. This round of expansion will be completed by early Q3 2021, with more expected as partners continue to scale their demand.
Introduction of 200mm dia. SiC will occur later in 2021
The increased R&D capacity will be used to further the Company’s efforts on SI CrystX® SiC and its transition to larger 200mm boules. As 5G continues to roll out globally, the need for semi-insulating SiC will accelerate. There are many RF-related applications for SI SiC, and GTAT’s R&D efforts are focused on bringing this to market quickly. In addition, the transition from 150mm to 200mm diameter SiC is necessary to boost yields. The 78% increase in wafer surface area means a corresponding increase in the number of devices, which helps lower cost. “Higher quality and bigger-diameter boules are parallel efforts for us,” said Knight. “We are moving very rapidly in response to a very dynamic and fast-growing set of markets.”
From EV’s to 5G, the global push to ‘electrify everything’ is resulting in a need for circuits and devices that have performance capabilities that extend well beyond those afforded by silicon. While SiC is seen as a front-running material to meet this challenge, demand for it far exceeds supply. This is because most producers of silicon cannot add SiC to their portfolios without investing in an entirely new process and undergoing a very steep learning curve. This is where a ‘pure-play’ SiC producer such as GTAT becomes valuable on a global scale. As GTAT boosts the ‘non-captive’ global supply of high-yield, high-quality SiC, devices made from SiC become more affordable. This means higher performance and lower system-level costs. In practical terms, EVs can enjoy better range thanks to increased use of more electrically efficient SiC. Also, the affordability index for EVs will increase over time as SiC becomes more prevalent.
GTAT will be expanding its production capacity by 60% in 2021.