About the speakers
Niels Posthuma
After finishing his electrical engineering studies at the University of Twente, in the Netherlands in 2000, Niels Posthuma started his PhD research at imec, Leuven, Belgium. He received his PhD degree from the faculty of engineering of the Catholic university of Leuven in April 2006 on germanium photovoltaic devices. Afterwards his work at imec was focussed on the development of high efficiency silicon solar cells. From 2009 to 2013 he was leading imec’s activities on interdigitated back contact (IBC) silicon solar cells. From 2013 onwards he is working as a principal member of the technical staff on the development of GaN based power transistors, specifically on p-GaN gate HEMTs for various voltage range applications. Since January 2021 he is the team leader of the GaN power process integration team.
Matteo Borga
Dr. Matteo Borga received the Master degree in Electronic Engineering at University of Padova in 2016, with a thesis on the analysis of degradation of normally-off p-GaN gate HEMTs. In 2020, he received his PhD degree in Information and Communication Science and Technologies from University of Padova, during which he focused on the stability and reliability of GaN-based power devices. He joined imec in 2019 as R&D engineer, where he is working on different architectures of GaN-based power devices design and characterization, with a focus on devices physics and reliability.
Olga Syshchyk
Olga Syshchyk was born in Ukraine. She received the B.S in Electrical Engineering and M.Sc. in Applied physics from Taras Shevchenko National University of Kyiv in 2013 and 2015, respectively. In 2014 she worked on the development of carbonfluoroxide nanoparticles for theranostic applications in National Institute of Applied Sciences in Lyon (France). She did her master thesis in Forschungszentrum Julich (Germany) on the investigation of the thermo-diffusion effect for different charged colloids. In 2017 she started her PhD research which include the device design, fabrication, defect analysis and electrical characterization of III-V devices. She received her PhD degree in Electrical Engineering at KULeuven under the supervision of Prof. Chris Van Hoof and Prof. Bob Puers. In 2020, she joined the GaN power electronics group in IMEC as process integration engineer, with a focus on GaN-ICs.
Abstract
Gallium nitride (GaN) is anticipated to be the next-generation power semiconductor. With a higher breakdown strength, faster switching speed, higher thermal conductivity and lower on-resistance, power devices based on GaN significantly outperform Si-based power chips. The first-generation GaN-based power devices will play a key role in the power conversion within battery chargers, smartphones, computers, servers, automotive, lighting systems and photovoltaics. Today, GaN is grown on a variety of substrates, including sapphire, silicon carbide (SiC) and silicon (Si). Imec takes today gallium nitride on silicon (GaN-on-Si) e-mode and diode technology to a higher level of maturity and explores the next generation GaN technology with higher level of integration (GaN-IC) and higher performances. In this mini-course we will highlight 3 different parts of the GaN power technology. The p-GaN gate HEMT device architecture is the technology of choice for lateral enhancement mode devices. The technology and challenges of this device concepts will be detailed. A second topic is a more exploratory device concept, which is the technology of (semi-)vertical GaN power devices. In a vertical device, the source and gate are at the surface, while the drain is at the bottom of the epi stack. For a vertical device, going to higher voltages boils down to creating a thicker epi stack because source and drain are located on different ends of the stack. As a consequence, the chip’s surface area doesn’t increase with increasing breakdown voltage. Finally, the technology of GaN-ICs where lateral e-mode HEMTs are monolithically integrated with various other device types such as Schottky Barrier Diodes, depletion mode HEMTs, resistors, logic transistors, will be discussed. The creation of monolithically integrated GaN-ICs paves the way toward smaller and more efficient DC/DC converters and Point-of-Load converters.