Owing to low conduction/switching loss, high switching frequency and high operating temperature, wide bandgap SiC and GaN power devices are attractive for next-generation power electronic systems with increased efficiency and power density. Because of the superior performance, SiC and GaN power devices could be in position to compete with the mainstream Si power devices in a variety of applications, including household appliances, photovoltaic inverters, electric vehicles, data centers, etc. Despite numerous research efforts devoted to material growth, device fabrication and circuit demonstration in the past decades, wide bandgap power semiconductor devices are still confronted with challenges that need to be addressed through new structure design and advanced process development. In this talk, we will review recent progress in SiC and GaN power devices, including the following. (1) High-density of interface traps usually exist at the gate-oxide/SiC interface in SiC MOSFETs, presenting a critical challenge to the channel mobility and device stability. Interface engineering techniques for SiC MOSFETs (e.g. NO/N₂O annealing, P incorporation, metal interfacial-layer, high-k dielectric deposition, etc.) and their impact on interface trap distribution as well as channel mobility will be discussed. (2) Long-term reliability of SiC MOSFETs with special focus on time-dependent dielectric breakdown (TDDB) will be presented. (3) We will introduce our latest progress in design and fabrication of super junction SiC devices, which can break the fundamental limit of the conventional unipolar devices. (4) In GaN-based lateral power devices, the 2DEG channel is an inherent normally-on channel, due to the spontaneous and piezoelectric polarization effects. To achieve fail-safe operation and simpler gate drive circuit, normally-off device technology including p-(Al)GaN cap, barrier recess and plasma treatment in the gate region will be introduced and compared. (5) Gate stack engineering techniques toward high-reliability GaN MIS-HEMTs/FETs will also be presented.