Influence of gate material and stress voltage on post breakdown leakage current of high k dielectrics

The breakdown (BD) behaviour of Al/sub 2/O/sub 3/ dielectrics is investigated as a function of electrode material, stress voltage and thickness. Other than generally reported in the literature, two stable BD phases were found, even for metal electrodes, which is attributed to finite threshold energy for hard BD formation. This results in a limitation of the post BD current at product operation conditions and therefore opens up possibilities for target relaxation.