The Development of the Advanced Inspection System to Screen out the BPDs that Extend to Bar Shaped SSFs under Forward Biasing

Abstract

We are currently developing an inspection system that will provide a low-cost means of screening prior to shipment by fully visualizing latent 1SSF (single Shockley stacking fault) defects originating from basal plane dislocations (BPDs) that cannot be detected by current defect inspection systems. The system will capture not only the defects that expand into right triangles under relatively low-level forward bias, but also the defects that expand into more serious bar-shaped 1SSFs under relatively high-level forward bias, with a particular focus on capturing TED (threading edge dislocation)-converted BPD at or below the buffer layer/substrate interface. Since these defects are known to cause forward voltage degradation during device operation, so-called "burn-in" (accelerated current stress) screening operation is currently utilized in some device manufacturers to avoid the shipping of the defective devices, but it is very time-consuming process which raises a total cost of production. The system we are developing, which can significantly reduce the screening time, has the potential to replace the "burn-in" operation.