Please outline your work at CEA-Leti, briefly explain Smart Cut™ technology and describe your role in its development.
I joined CEA-Leti in 1992 to develop new silicon on insulator (SOI) products for Soitec, which had spun-off from the CEA-Leti a few months earlier. I led the team that developed the Smart Cut process with Soitec. Our objective was to develop the process, understand the physical mechanisms involved, build prototypes and protect our inventions through intellectual property patents. In parallel, I was leading the thin film and circuits laboratory at CEA-Leti, where I was in charge of both the joint program on Smart Cut with Soitec and the development of new technologies to transfer partially or fully processed layers onto different substrates.
Smart Cut, Soitec’s proprietary wafer bonding and layer splitting technology, makes it possible to transfer ultra-thin single crystal layers of material from a donor substrate to another substrate through implantation of light ions and wafer bonding. It works like an atomic scalpel and allows active layers to be managed independently from the supporting mechanical substrate. Today, this process is the industry standard for creating thin SOI wafers.
What prompted you to found Tracit Technologies, a CEA-Leti spin-off, and what was the focus of the company?
In 2001, there was increasing market interest in technologies enabling the transfer of partially processed layers. I decided to offer an industrial solution based on the technologies developed by CEA-Leti, so I founded Tracit Technologies in 2003.
The company focused on the transfer of thin film and circuit layers to different substrates or supports. When Soitec acquired Tracit Technologies, it was a specialist in transferring a layer from a partially or fully processed wafer to another substrate (glass, ceramic, polycrystalline, fused silica, sapphire, etc.) to best meet a customer’s specific needs and improve performance. RF applications, backside illumination image sensors and MEMS were, and still are, typical applications for this technology.
How did you originally view the acquisition of Tracit Technologies by Soitec in 2006 and what is your role in the company now?
As an expert in layer transfer, Tracit Technologies was a natural fit with Soitec’s strategy. Indeed, its acquisition opened up additional market opportunities for the company and further leveraged its proprietary Smart Cut technology. By offering the ability to transfer processed layers, Tracit Technologies’ expertise in layer transfer (later rebranded as Smart Stacking™) presented an opportunity for Soitec to extend its product lines to other applications. As for Tracit Technologies, we were qualified by several customers and were seeking to increase our industrial capacity.
Today, I am executive vice president of Soitec and general manager of the Communication & Power business unit, offering mainly RF SOI and power SOI products for RF front-end modules and automotive applications.
Outline, in general terms, Soitec’s RF SOI capability and the ecosystem involved in the definition and development of substrates for RF.
Historically, GaAs was the mainstream substrate for cellular front-end module switches, and bulk silicon was mainstream for digital and biasing control circuits. Soitec first entered the smartphone market with silicon on sapphire and high resistivity SOI (HR SOI) substrates. Later on, we developed a revolutionary trap-rich layer for RF SOI wafers with the Université Catholique de Louvain (UCL) that made it possible to combine silicon CMOS circuits on a quasi-ideal RF substrate. RF SOI wafers bring high linearity, high isolation for 3G, 4G and beyond, as well as low insertion loss. They are more cost efficient than GaAs and MEMS technologies and enable high integration of switches, LNAs, PAs, passives, logic, etc. With such benefits, RF SOI became a standard in front-end modules within just a few years. It is now in 100 percent of smartphones and more than 10 foundries are currently offering RF SOI technology.
Further developments of the technology are ongoing to address the next RF requirements (uplink carrier aggregation, massive MIMO, 5G, etc.). The rapid and massive adoption of RF SOI by the industry has been made possible thanks to collaborations throughout the ecosystem and Soitec’s close work with fabless companies and foundries. Collaboration across the ecosystem is essential, as substrates, processes and designs are tightly linked together to deliver performance at the right cost.
For future networks, we are continuing to work closely with both fabless companies and foundries to understand the requirements and challenges for all their products and use our knowledge to build new generations of substrates. Soitec solutions for RF applications are moving beyond front-end modules. Actually, another type of SOI substrate — fully depleted SOI (FD SOI) — provides unique analog/RF characteristics for various RF devices, such as transceivers or chips integrating digital and analog/RF functions.
Explain the technologies employed and the products produced at your manufacturing plants in Bernin, France.
We have three facilities in Bernin. One is for the production of 200 mm wafers, and one is for 300 mm wafers. In addition, we have a production line for compound and other non-silicon materials. We use our toolbox of technologies and our materials expertise to develop tailor-made products meeting the needs of four high-growth, mass-volume markets: smartphones, automotive, the Internet of Things (IoT) and data centers. We also see many opportunities in emerging markets, such as augmented reality (AR), virtual reality (VR) and artificial intelligence (AI), where engineered substrates will bring unique performance and enable mass adoption.
Please explain the products produced at your manufacturing plants in Singapore and China.
We have a 300 mm fab in Singapore that is currently on standby, but we are planning to re-start it to address expected strong demand for FD SOI wafers. In China, we have a strategic partnership with Shanghai Simgui Technology Co., Ltd. (Simgui), a Chinese silicon-based semiconductor materials company. Through this agreement, Simgui can use our proprietary Smart Cut technology to manufacture and sell 200 mm SOI products in China. This agreement strengthens the SOI ecosystem globally and addresses China’s fast-growing demand for 200 mm SOI wafers in RF and power semiconductor markets.
Geographically, where is the company witnessing the greatest expansion and in what technology sectors?
The USA, Europe and Asia are all important growth markets for us in the RF and power sectors, but we also anticipate high growth in digital and emerging SOI, as well as MEMS.
The number one application for Soitec’s products is in smartphones. Explain briefly the drivers for growth and identify where there are additional revenue opportunities in this sector.
As mentioned earlier, the RF SOI product line has become the standard in front-end modules for antenna tuners and switches, because the technical performance it delivers helps to cope with the rising number of frequency bands and higher data speed requirements of mobile communications. Therefore, despite the slow growth of the global mobile phone market, we anticipate substantial growth in RF SOI content, driven by the increasing number of devices (switches, antenna tuners, LNAs) and functions (diversity). And there is more potential for Soitec’s products in smartphones! Ultimate power efficiency with high-connectivity capabilities can be enabled with our substrate solutions.
Our FD SOI technology, delivering power-efficient digital computing, offers unique levels of analog/RF integration. As a planar 2D technology, FD SOI generates far fewer parasitics than any other technology available. For example, 22 nm FD SOI is able to achieve a sufficient level of ft/fmax to meet 5G millimeter wave frequency requirements. It is the ideal substrate for next-generation transceivers and system-on-chip (SoC) devices.
GPS, APU, ISP and sensors are additional areas where our existing and future products can help solve integration, power consumption and other challenges, bringing increased value to our customers and their customers. These devices could be based on FD SOI or RF SOI.
How important is the automotive sector to Soitec?
The automotive sector was an early adopter of the SOI technology. It has shown regular and continuous growth over the years, and it represents about 20 percent of our revenue today. Soitec has been serving this demanding market for several years and is fully ISO TS qualified.
Today, Soitec’s power SOI products are utilized in automotive applications, mainly for CAN/LIN transceivers and Class D amplifiers. With the development of electric/hybrid, autonomous and connected vehicles, the automotive market will become another key segment for Soitec products, including power SOI, RF SOI and FD SOI for advanced driver assistance (ADAS) applications, for example. FD SOI achieves a lower soft error rate (SER) compared to other CMOS technologies, opening huge opportunities for applications that require high reliability and zero processing failure rates.
Are there other areas where you see increased opportunities for the company’s RF SOI wafers?
Yes, many! Our RF SOI substrates can bring additional value in the IoT space, thanks to the great levels of integration they offer. In the automotive segment, our RF SOI substrates are well suited for use in radar systems. Another example is internet broadband low earth orbit (LEO) satellites.
How vital is innovation and research to Soitec, and are academic and industrial partnerships important?
Soitec is the SOI engineered substrate leader. Every year, we invest in R&D to deliver material innovation. It is in Soitec’s DNA. We work closely with academic organizations such as CEA-Leti, imec and UCL, as well as industrial partners, to deliver innovative solutions that strengthen our customers’ competitiveness. The close relationship that we have with our customers enables us to work today on the development of new materials for specific applications of tomorrow.
In addition to our unique Smart Cut and Smart Stacking technologies, we also have strong expertise in epitaxy and compound materials. As an example, we are able to transfer a thin layer of crystalline material such as GaN or InGaN or InP or piezoelectric materials to another substrate (silicon, sapphire, GaAs, etc.) to produce a variety of high quality, cost-effective wafers.
Finally, technologically, where do you see the future for Soitec and its products?
The RF SOI business is still growing and will remain an essential revenue stream for Soitec. In addition, further growth will be driven by our FD SOI technology for applications in markets such as smartphones, IoT and automotive. Power SOI also will remain a solid growth sector for us. Our portfolio of emerging SOI products (imagers/photonics) will play an increasingly important role as well.
Our technologies, our expertise in materials, wafer bonding and thinning, as well as our high volume manufacturing capability, position Soitec to be the leader in engineered substrates (SOI or other hetero-structures) in many high-growth markets.