PARIS — A trending narrative in Europe’s microelectronics industry recently is the comeback of French companies, as illustrated in an increased share of French tech designed into Apple’s iPhone X. Local media are almost giddy with the news, touting big wins by STMicroelectronics and Soitec in Apple’s new flagship iPhone model.
The good news coincides with both companies’ improved business operations in recent quarters, with rising revenue and net profits.
On one hand, to the trained eyes watching from Silicon Valley, this France-centric storyline seems a mite provincial. On the other hand, from outside of Silicon Valley’s own bubble, it’s not so difficult to understand why iPhone X represents a new milestone for France. The French see their technology prowess, backed by decades of foundational R&D by top researchers and engineers, breaking the bounds of an Imaging Valley tucked away near the French Alps and gaining worldwide recognition.
Thus far, both STMicroelectronics and Soitec are mum on their recent design wins. However, the latest iPhone X teardown done by Yole Développement in collaboration with its partner, System Plus Consulting, found ST’s NIR sensor inside iPhone X’s TrueDepth module. It was built using silicon-on-insulator (SOI) wafers developed by Soitec.
What’s so special about SOI wafers in ST’s NIR sensors? How are they different from other SOI wafers?
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In recent months, Soitec has also been busy talking up not just RF-SOI and FD-SOI, but Photonics-SOI, Imager-SOI and others. What are they, how are they engineered, and what are they for?
Earlier this month in Paris, EE Times sat down with Paul Boudre, Soitec’s CEO, for an interview.
Asked about Soitec’s evolving substrate technologies, Boudre first reminded us that Soitec isn’t just a wafer supplier. Its value creation lies in the development of engineered substrates. “Innovation is our core business,” said Boudre. Soitec’s mission is to find “new solutions” demanded by customers, and its customers’ customers. “We engineer new materials, and design to cost” to meet their needs, he explained.
Although Soitec won’t talk about ST or Apple, the key to Soitec’s big iPhone win is the specific SOI wafers the company developed for ST’s NIR sensors. Pierre Cambou, activity leader for imaging and sensors at Yole, deduced that SOI has played a critical role in improving the sensitivity of NIR sensors — so that ST can meet Apple’s stringent demands for quality and time to market.
Soitec’s close collaborations with research institutions like CEA-Leti, IMEC and the Université Catholique de Louvain have kept it in the forefront of innovation in SOI-engineered substrates.
Soitec takes a toolbox approach. “We build a common platform where those research organizations’ tools and Soitec’s own tools and expertise are combined,” Boudre said. This pays off when developing tailor-made products specific to Soitec’s customers and their customers.
There is more to Soitec’s “Smart Cut” and “Smart Stacking” technologies than meets the eye. They are critical in transferring a thin layer of materials to another substrate to produce a range of high-quality, cost-effective wafers. “We look at the resistivity of a given material, thickness of a layer and its uniformity,” said Boudre. “Our job is to model it, run pilots and validate with our customers.”
As a result, Soitec has introduced new materials for use in substrates and improved the cost of wafers, while launching a range of new SOI wafers for a variety of applications. They include: RF-SOI, FD-SOI, Power-SOI, Photonics-SOI and Imager-SOI.
RF-SOI for front-end modules, 5G
RF-SOI, for example, is widely used for front-end module integration in ultra-low power communication.
Over the last decade, types of materials and the structure of layers in RF-SOI wafers have evolved, allowing Soitec to develop a tuned substrate that delivers the better RF performance required by a new generation of cellular standards.
Historically, GaAs was the mainstream substrate for cellular front-end module switches. Soitec originally entered the smartphone market with silicon on sapphire and high resistivity SOI (HR SOI) substrates.
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