The fact that GaN is a suitable candidate to replace silicon in many power systems is not a question anymore. As reported in “Power GaN 2018: Epitaxy, Devices, Applications and Technology Trends” from Yole Développement (Yole), even if GaN currently still holds only a small share of the market it has a good outlook for the coming years. During 2018, several high-end power supply products have been released, mainly related to computers, data centers or fast charging consumer products. More products are expected to be launched in 2019-2020, increasing GaN volumes and $M revenues will finally arrive. Moreover, we have perceived new companies showing interest in entering the GaN market: both fabless and IDMs. For some of the IDMs, the promotion of GaN technology comes but a short time after the inclusion of power SiC in their portfolio.
(Courtesy of STMicroelectronics)
A good example of expansion of GaN into IDMs is STMicroelectronics (ST): last summer the use of ST SiC MOSFETs in the main inverter of Tesla Model 3 was unveiled, as reported by System Plus Consulting in “Tesla Model 3 Inverter with SiC Power Module from STMicroelectronics”. This action revolutionized the EV market and many OEMs are pushing harder to introduce SiC into their inverters. This September, ST showed itself also active in Power GaN development, announcing that the company will create a fully qualified manufacturing line, including GaN-on-Si hetero-epitaxy, for initial production running in the company’s front-end wafer fab in Tours, France, by 2020. Today, Yole has the opportunity to meet Filippo Di Giovanni, Power RF & GaN Product Unit Manager in STMicroelectronics to discuss the power GaN development collaboration with CEA-Leti and the GaN power roadmap for the coming years.
This interview has been conducted by Ana Villamor, PhD., Technology & Market Analyst, Power Electronics (AV), Hong Lin, PhD., Senior Technology & Market Analyst, Compound Semiconductors & Emerging Materials (HL), and Ezgi Dogmus, PhD., Technology & Market Analyst, Compound Semiconductors & Emerging Materials (ED) at Yole Développement.
Ana Villamor (AV), Hong Lin (HL) & Ezgi Dogmus (ED): STMicroelectronics recently teamed up with CEA for GaN power activity. Could you tell us more about this collaboration?
Filippo Di Giovanni (FDG): The CEA-Leti partnership lets us collaborate in the design and development of intrinsically normally-off GaN HEMTs (high-electron-mobility transistors) and diodes by building on Leti’s IP and ST’s know-how in power technology processes. We’ll stage development at the Leti 8” pilot line in Grenoble and move the technology to ST’s Tours, France, 8” production fab when the technology is sufficiently mature. The GaN products we’ll develop will complement ST’s broad STPOWER™ portfolio of power technologies in silicon (Si) and silicon carbide (SiC).
AV, HL & ED: STMicroelectronics has also announced cooperation in GaN RF activity with MACOM. Is there any synergy between these two activities?
FDG: No, these are two independent activities. There is no connection between the activities with MACOM and CEA-Leti. The work with MACOM is aimed at developing GaN on Silicon specifically for the RF market. We’re doing this work in ST Catania and it will allow MACOM to better participate in the fast growing market of Telecom infrastructure, while ST can use the same technology to address non-Telecom sectors such as ISM (Industrial, Scientific and Medical), Avionics and RF Energy.
(Source: Power GaN 2018: Epitaxy, Devices, Applications and Technology Trends, Yole Développement, November 2018)
AV, HL & ED: Yole understands that STMicroelectronics has a very active SiC business. How does STMicroelectronics position SiC and GaN in its product portfolio?
FDG: ST is investing in the development of both these breakthrough technologies. SiC MOSFET is almost perfect for 1200V (and higher) class devices. GaN cannot achieve such high voltages due to its lateral structure. There might be some overlap at around 650V, but this is only for lower frequencies, as GaN technology clearly performs better at very high switching frequencies of around 1 MHz. Below 600V, GaN again is the clear winner, but in this range it competes with silicon technologies, not SiC. In short, SiC MOSFETs are ideal for high voltage and high power applications, while GaN is better for lower voltage and lower power applications, but with high switching frequencies.
AV, HL & ED: Automotive is one of the most important drivers of the power electronics market. What will be the role of GaN in the automotive market? And what is the time to market?
FDG: GaN is expected to be the mainstream switch for PFC (power factor correction) in EV (electrical vehicle) on-board chargers (OBC) and for 48V battery mild hybrid projects that most automotive makers are planning in the coming years. The time to market will depend on the rate at which the technology matures, and at which we can build our insight into failure mechanisms and reliability responses that do not necessarily coincide with those of silicon. Given the lifecycles in automotive, ramp-up can be expected sometime after 2022
(Courtesy of STMicroelecronics)
AV, HL & ED: What is your opinion of D-mode and E-mode devices? What are the respective application targets?
FDG: All power conversion applications, including those already addressed by MOSFETs, IGBTs and SiC transistors, require E-mode switches. In RF applications, where the transistor functions as a power amplifier, the device can be D-mode.
AV, HL & ED: What differentiates your GaN products, such as GaN transistors and GaN-on-Si diodes, from others?
FDG: ST possesses in-depth knowledge and expertise in packaging, especially at very high frequencies. This, along with manufacturing excellence, is ST’s differentiating factor.
AV, HL & ED: What are the main parameters for choosing a package? Which would be the best approach from the point of view of STMicroelectronics for your target applications for GaN?
FDG: Without giving away too much of our expertise, dissipation capability (for instance dual-side cooling) and low parasitic inductance are two key parameters for choosing a package.
(Source: Tesla Model 3 Inverter with SiC Power Module from STMicroelectronics, System Plus Consulting, June 2018)
AV, HL & ED: What is the developmental status of your GaN product?
FDG: 650V product prototypes are expected in H2 2019.
AV, HL & ED: Please tell us your product road map for the next five years?
FDG: Following 650V, we’d expect to introduce 100V – 200V, followed by integrated solutions in both packaged and monolithic options.
Filippo Di Giovanni is currently working for the Power Transistor Division STMicroelectronics, in charge of the Power RF & GaN Product Unit at ST Catania, Italy. Filippo has a university degree in electronic engineering and more than 30-years’ experience in power transistors, including bipolar, MOSFETs, IGBTs, SiC, and GaN. His activities include product development and handling technology partnerships in LDMOS and GaN HEMTs in both RF and power conversion fields.
Ana Villamor, PhD serves as a Technology & Market Analyst, Power Electronics & Compound Semiconductors within the Power & Wireless division at Yole Développement (Yole). She is involved in many custom studies and reports focused on emerging power electronics technologies at Yole Développement, including device technology and reliability analysis (MOSFET, IGBT, HEMT, etc). In addition, Ana is leading the quarterly power management market updates released in 2017. Previously Ana was involved in a high-added value collaboration related to SJ Power MOSFETs, within the CNM research center for the leading power electronic company ON Semiconductor. During this partnership and after two years as Silicon Development Engineer, she acquired a relevant technical expertise and a deep knowledge of the power electronic industry. Ana is author and co-author of several papers as well as a patent. She holds an Electronics Engineering degree completed by a Master in micro and nano electronics, both from Universitat Autonoma de Barcelona (SP).
As a Technology & Market Analyst, Compound Semiconductors, Ezgi Dogmus, PhD is member of the Power & Wireless division at Yole Développement (Yole). She is daily contributing to the development of these activities with a dedicated collection of market & technology reports as well as custom consulting projects. Prior Yole, Ezgi was deeply involved in the development of GaN-based solutions at IEMN (Lille, France). Ezgi also participated in numerous international conferences and has authored or co-authored more than 12 papers. Upon graduating from University of Augsburg (Germany) and Grenoble Institute of Technology (France), Ezgi received her PhD in Microelectronics at IEMN (France).
Hong Lin, PhD works at Yole Développement (Yole), as a Senior Technology and Market Analyst, Compound Semiconductors within the Power & Wireless division since 2013. She is specialized in compound semiconductors and provides technical and economic analysis. Before joining Yole Développement, she worked as R&D engineer at Newstep Technologies. She was in charge of the development of cold cathodes by PECVD for visible and UV lamp applications based on nanotechnologies. She holds a Ph.D in Physics and Chemistry of materials.
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