STMicroelectronics and Leti cooperating to industrialize GaN-on-Silicon for power conversion applications
STMicroelectronics, a global semiconductor leader serving customers across the spectrum of electronics applications, and Leti, a research institute of CEA Tech, are to industrialize GaN (Gallium Nitride)-on-Silicon technologies for power switching devices. This power GaN-on-Si technology will enable ST to address high-efficiency, high-power applications, including automotive on-board chargers for hybrid and electric vehicles, wireless charging, and servers.
The collaboration focuses on developing and qualifying advanced power GaN-on-Silicon diode and transistor architectures on 200mm wafers—a market that the research firm IHS Markit estimates to grow at a CAGR of more than 20 percent from 2019 to 2024. Together, in the framework of IRT Nanoelec, ST and Leti are developing the process technology on Leti’s 200mm R&D line and expect to have validated engineering samples in 2019. (Nanoelec Research Technological Institute (IRT), headed by Leti, conducts research and development in the field of information and communication technologies (ICT) and, specifically, micro- and nanoelectronics.)
In parallel, ST will set up a fully qualified manufacturing line, including GaN/Si hetero-epitaxy, for initial production running in ST’s front-end wafer fab in Tours, France, by 2020.
In addition, given the attractiveness of GaN-on-Si technology for power applications, Leti and ST are assessing advanced techniques to improve device packaging for the assembly of high power-density power modules.
As a wide-bandgap semiconductor material, GaN devices inherently allow operation at much higher voltages, frequencies, and temperatures than conventional semiconductor materials such as silicon. ST is also working on two other wide-bandgap technologies: silicon carbide (SiC) and RF Gallium Nitride (GaN)
In GaN, in addition to this announcement with CEA-Leti, ST recently announced another development of GaN-on-Silicon for RF applications with MACOM, for MACOM’s use across a broad range of RF applications and for ST’s own use in non-telecom markets. While easy to confuse because both use GaN, the two efforts use structurally different approaches that have different application benefits. These include the suitability of the Power GaN-on-Si technology to be produced on 200mm wafers, while the RF GaN-on-Silicon is—for now, at least—better suited for 150mm wafers. Either way, because they produce low switching losses, GaN technologies suit higher frequency applications.
SiC devices, on the other hand, operate at higher voltages with a blocking voltage of more than 1700V, an avalanche rating over 1800V, and low on-resistance making it ideal for energy efficiency and thermal performance. With these characteristics, SiC is an excellent fit in applications such as electric vehicles, solar inverters, and welding equipment.