Defect generation statistics in thin gate oxides |
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Authors: | Ielmini D Spinelli AS Lacaita AL van Duuren MJ |
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Affiliation: | Dipt. di Elettronica a Informazione, Politecnico di Milano, Milan, Italy; |
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Abstract: | We analyze data-retention experiments for flash memory arrays with thin tunnel oxide (t/sub ox/ = 5 nm). These samples show an additional conduction mechanism besides Fowler-Nordheim tunneling and stress-induced leakage current (SILC). The additional leakage contribution is analyzed with respect to the spatial distribution in the array and the shape of the current-voltage characteristics, and is interpreted as an anomalous SILC due to a two-trap leakage path. From the cycling dependence of the distribution tails related to one- and two-trap leakage, we provide evidence that the defect generation statistics is not Poissonian, but is instead correlated. Possible physical mechanisms responsible for correlated generation are also discussed. |
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