Polarity dependent breakdown of the high-κ/SiOx gate stack: A phenomenological explanation by scanning tunneling microscopy

Applied Physics Letters (Impact Factor: 3.79). 06/2008; DOI:10.1063/1.2926655
Source: IEEE Xplore

ABSTRACT From scanning tunneling microscopy, we present unambiguous evidence of thermally induced localized conduction paths exhibiting an asymmetrical conduction property in the high- κ gate stack. The tunneling current under gate injection biasing is found to be much larger than that under substrate injection biasing after a 700 ° C postdeposition anneal, i.e., the localized paths exhibit a much lower resistance under gate injection biasing. This finding provides a phenomenological explanation for the polarity dependent breakdown of the high- κ gate stack as observed from electrical stressing of large-area metal-oxide-semiconductor capacitors.

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