They found that the issue stems from dislocation defects, which disrupt the crystal structure, leading to leakage and reduced performance. The team found these defects because GaN has a hexagonal atomic structure, which makes it different from silicon’s cubic structure.
This differs from silicon defects, which are typically caused by gliding (a movement along a plane), which the industry has learned to control. GaN defects, on the other hand, are primarily due to climbing (changes in the number of local atoms), a process that has been poorly understood until now.