The ‘Permanent’ Component of NBTI: Composition and Annealing

A number of recent publications explain NBTI to consist of a recoverable and a more permanent component. While a lot of information has been gathered on the recoverable component, the permanent component has been somewhat elusive. We demonstrate that oxide defects commonly linked to the recoverable component also form an important contribution to the permanent component of NBTI. As such, they can contribute to both the threshold voltage shift as well as to the charge pumping current. Under favorable conditions, particularly when subjected to continuous charge-pumping measurements, the permanent component can show recovery rates comparable to that of the recoverable component. We argue that this enhanced recovery is due to a recombination enhanced defect reaction mechanism. We introduce a simple extension to our switching trap model to also capture the impact of charge pumping measurements on the transition rates between the defect states.