Blistering of Al2O3/a-SiNx:H stacks: analysis of the submerged part of the iceberg by colored picosecond acoustic microscopy

Blistering of Al
₂
O
₃
/SiN
_X
:H stacks has been regularly reported over the last decade. Despite several studies, it has not been possible to link blistering density and lifetime degradation. In this work we demonstrate the use APiC technique to probe the c-Si/Al
₂
O
₃
interface. It allows us to show that it might not be the delaminated surface fraction which rules the lifetime degradation but most likely the interface quality of non-delaminated areas. Blistering is the top of the iceberg; characterizing the interface with the high sensitivity provided by APiC is a breakthrough.