Extraction of recoverable and permanent trapped charge resulting from negative bias temperature instability

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Abstract

We have studied defect charging and discharging resulting from negative bias temperature instability in nitrided SiO2 gate insulator field effect transistors. Using pseudo-DC and pulsed stressing methods, we are able to extract at least three individual components associated with a) interface states at the semiconductor/insulator boundary, b) dynamically recoverable positive charging in the “bulk” of the insulator, and c) positive charge in the insulator which can be “eliminated” by application of a positive electric field across the insulator. It is argued that the charge variation in c) in fact arises via a charge neutralization process involving electron capture at switching traps and that this process can be simply reversed using a small negative field. The important role played by neutral oxygen vacancies (O3≡Si-Si≡O3) and/or their variants involving partial N substitutions is emphasized. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

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