Short Course I – Power Electronics
Correlation of metrology data with electrical performance of lateral p-GaN HEMT devices
Izabela Kuzma-Filipek – imec, Belgium
Gallium nitride (GaN)-on-Si technology for power and RF applications requires robust defect characterization across both blanket epitaxial wafers and patterned device structures to ensure high yield, reliability, and electrical performance. A combination of optical, electron-beam, and electrical metrology techniques can provide complementary insights into defectivity at different process stages. On blanket GaN-on-Si wafers, optical inspection, photoluminescence (PL) mapping, X-ray diffraction (XRD), atomic force microscopy (AFM), and defect-selective etching are commonly employed to quantify threading dislocation density, surface morphology, stress variation, and epi-uniformity. For patterned wafers, high-resolution optical inspection, SEM review, e-beam defect inspection, scanning probe techniques, and nanoprobing enable identification of process-induced defects such as gate damage, p-GaN etch residues, metal discontinuities, particle contamination, and dielectric failures. Correlation of metrology data with electrical test results provides valuable insight into defect impact on device performance. For p-GaN HEMTs, regions exhibiting elevated threading dislocation density or abnormal PL signatures often correlate with increased off-state leakage current and reduced breakdown voltage. Localized surface defects and gate-edge process excursions detected by patterned wafer inspection have been linked to increased gate leakage, threshold voltage variation, and reduced device yield. Additionally, defect clustering identified through optical or e-beam inspection can show strong spatial correlation with wafer-level maps of dynamic RDS(on), IDSS leakage, and early reliability failures. By combining high-sensitivity defect inspection with electrical parametric and reliability characterization, a comprehensive defect-to-performance framework can be established, enabling root-cause identification, process optimization, and improved manufacturability of p-GaN HEMT technologies.
Izabela Kuzma-Filipek received her master degree (2004) in Material Engineering from AGH University of Cracow (Poland) in collaboration with EMPA Institute (Switzerland) and her Ph.D. degree (2010) in Electrical Engineering from KU Leuven Belgium. Dr. Kuzma was a Postdoctoral Researcher at the department of Si Photovoltaics at imec and subsequently senior scientist and project manager at the same department. In 2020 Dr Kuzma started new position in GaN Power Electronic department of imec as a senior researcher and project manager. Main areas of expertise: compact devices integration, failure analysis.
Packaging of GaN devices for highest Power densities
Ali Roshanghias – Silicon Austria Labs, Austria
Although GaN devices offer superior switching speed, efficiency, and power density, the full exploitation of their capabilities is often hampered by conventional packaging technologies. This short course explores advanced interconnect and heterogeneous integration technologies for GaN packaging in both RF and power applications. It will address top-side interconnects in chip-on-board GaN micro-assemblies, ultra-fine-pitch flip-chip techniques, and 3D die stacking, highlighting how these approaches reduce parasitic effects, improve thermal management, and enable highly integrated, high-power-density GaN systems.
Dr. Ali Roshanghias is the head of the research unit for heterogeneous integration technologies at Silicon Austria Labs (SAL). He received his Ph.D. in materials science and technology in 2012. He pursued his career as a post-doc researcher in Japan and Austria in the fields of electronic materials and advanced microelectronics packaging. In 2015 he joined SAL (formerly known as CTR Carinthian Tech Research AG). He is the author of more than 100 scientific papers and patents and serves as a lecturer at the University of Klagenfurt. Ali has also served as the work package leader for integration and packaging of GaN devices in the European All2GaN project in the last 4 years.
