Defect Mechanics-Based Multiscale Simulation Techniques

Safety and reliability are the major issues for high-performance electronic devices working in the space environment due to harsh working and environmental conditions. Therefore, it is matter of prime importance to consider the working environment of these devices at the fabrication and working stage. GaN-based electronic devices such as LDs, LEDs, GaN gas sensors, HEMT, wireless communication and signaling devices are becoming popular for lighting, sensing, switching, signaling, and communication purposes. These devices are fabricated on a substrate such as sapphire or silicon. Defects such as dislocations and cracks are formed in the GaN because of high lattice and thermal mismatch between the GaN and the substrate. These defects can become a major issue for reliability of these devices. This research will be focused on studying the mechanics of defect generation in GaN layer using multiscale simulation technique so that defect density can be reduced which can contribute in improving the reliability of these devices in harsh working environments that arise in aerospace applications. The multiscale research comprising of ab-initio, molecular dynamics, dislocation dynamics and continuum mechanics will be employed in understanding the defect generation processes, and its effect on the performance and reliability of these devices. Proper considerations of harsh working environment for these devices will be taken into account while conducting theoretical and simulation-based studies of the defect mechanics at various scales. Appropriate design considerations and device fabrication processes will be suggested based on the multiscale studies carried out during this research