ABSTRACT. The performance and reliability of an electrical device is decisive for its application and wider usage. Novel devices often show an outstanding performance in laboratory environment but have to survive field conditions and perform free of failure for a long time. If a failure of the device occurs, the origin has to be identified and may have various causes ranging from materials defects over processing issues, packaging problems and others. This tutorial will pick up this topic from a materials point of view and will discuss what defects in the materials are considered relevant for the electrical function of a nitride device and how such materials defects can be analyzed. Thereby, materials issues in the substrates starting from crystal growth of GaN and AlN will be discussed as well as defects in epitaxial layers for device structures. The tutorial points out a possible methodology how to identify key defects in nitride materials with respect to the performance of a power device.

ABSTRACT. The vertical structure of the power device has advantages such as small chip size, easy wiring, and high breakdown voltage. Furthermore, wideband gap semiconductors have the greatest feature of low on-resistance. GaN is a material having the ability to fully exhibit these properties and in recent years development of GaN vertical devices has been accelerated. For example, GaN vertical devices with over 1kV breakdown voltage have been reported recently. Moreover, over 3kV pn diodes were also reported. Therefore, ability of GaN for high voltage devices has already been proven. Next issues are developments of fabrication process technologies which make devices stable operation. In this presentation, we will report recent our advances in process technologies for GaN vertical devices, which are high quality GaN epitaxial growth technology, dry etching technology for trench forming of MOSFET, and Mg ion implantation and its activation for p-GaN. Especially, the Mg ion implantation will make it possible to expand the freedom of the device design and simplify the device process.

ABSTRACT. With an increasing amount of electrification projects in aviation, reliability becomes a key question. Integrating electric and electronic equipment in areas that have been dominated by thermal machines poses big challenges and opportunities. This presentation will provide insights into the methods used to determine the required reliability by assessing the whole system and exploring the electromechanical and environmental interactions that define the new requirements to be met. Finally, it will discuss the interlinked nature between safety and reliability in aviation.

ABSTRACT. It is remarkable that semiconductor technology is more advanced in its capacity to create complex systems than in the ability to image the outcomes. Conventional high-resolution microscopy for imaging the interior of three-dimensionally structured objects typically entails destructive sample preparation followed by electron microscopy of resulting surfaces or sections. Here we describe X-ray ptychography, a mixed real space/reciprocal space („wavelet“) technique, which is non-destructive and provides three-dimensional images at steadily improving resolution, which have now reached 15 nanometers. We show applications to integrated circuit inspection, and describe implications for security and quality control.

ABSTRACT. The state-of-the-art power switching devices made from GaN semiconductors contain a high density of crystal defects, especially in the thick epitaxial layers. Most of these defects are present initially in starting wafers and some are generated during device processing. There is little conclusive evidence so far on the exact role that the crystal defects play on device performance, manufacturing yield, and more importantly, long-term field-reliability especially when devices are operating under extreme stressful high voltage environments. This paper provides the progress of characterization of thick GaN power semiconductor material epitaxial layers and growth technology, and the potential impact crystal defects may have on high-density power switching electronics. A comparison of the SiC development and manufacturing evolution is made to draw a parallel between SiC and GaN wide bandgap (WBG) semiconductor power electronics.