Degradation and breakdown of 0.9 nm EOT SiO/sub 2/ ALD HfO/sub 2/metal gate stacks under positive constant voltage stress

By means of leakage current measurements, charge pumping and TDDB analysis, we construct a consistent model for the degradation and breakdown of 0.9 nm EOT atomic layer deposited (ALD) HfO2. During degradation, traps and two-trap clusters are formed in the HfO 2 giving rise to considerable SILC. The two-trap clusters subsequently wear out, finally leading to an abrupt hard breakdown. We demonstrate that 0.9 nm EOT ALD HfO2 is intrinsically reliable under constant voltage stress if hard breakdown is used as a failure criterion