Reliability aspects of GaN based power devices for high voltage switching applications

Summary form only given. GaN based power devices for high efficiency switching applications in modern power electronics are rapidly moving into the focus of world wide research and development activities. Due to their unique material properties GaN power devices are distinguished by featuring high breakdown voltages, low on-state resistances and fast switching properties at the same time. Finally, these properties are the consequences of extremely high field and current densities that are possible per unit device volume or area. Therefore, in order to obtain very high performance, the material itself is stressed significantly during standard device operation and any imperfection may lead to wear out and reliability problems. Thus material quality, the specific epitaxial design as well as the device topology will directly influence device performance, reliability and mode of degradation. The tutorial will mainly discuss those degradation mechanisms that are especially due to the specific material combinations used in GaN based high voltage device technology such as epitaxial layer design, chip metallization, passivation schemes and general device topology and layout. It will then discuss technological ways towards engineering reliability into these devices.