Impact of morphological defects on the electrical breakdown of ultra thin atomic layer deposition processed Al₂O₃ layers

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• 作者：Holger Spahr ; Tim Bü ; low ; Christine Nowak ; Felix Hirschberg ; Johannes Reinker ; Sami Hamwi ; Hans-Hermann Johannes ; ^{h2.johannes@ihf.tu-bs.de} ; Wolfgang Kowalsky
• 关键词：Atomic layer deposition ; Ultra-thin layers ; Defects ; Electrical breakdown ; Disruptive strength ; Dielectric properties ; Al2O3
• 刊名：Thin Solid Films
• 出版年：2013
• 出版时间：1 May, 2013
• 年：2013
• 卷：534
• 期：Complete
• 页码：172-176
• 全文大小：446 K

文摘

We report on the continuous increase of the breakdown electric field, also known as disruptive strength, of an ultra thin layer based on Al₂O₃ prepared by low temperature atomic layer deposition (ALD) by reducing its thickness down to 3 nm. By measuring the disruptive strength for lower thicknesses, we demonstrate that these observations are in agreement with recent reports. Furthermore we detected an increase within the disruptive strength towards lower thicknesses together with a rise of the pin hole density. The pin holes, originating from an inhomogeneous growth of the dielectric and referred to as morphological defects and current conducting paths, are detected by Cu electroplating and result in a lower permittivity of the dielectric. As a conclusion, the dielectric breakdown of thin, low temperature ALD processed Al₂O₃ layers does not seem to be negatively influenced by the increase of the pin hole density. Thus, the increase of the disruptive strength is either due to the morphological defects in the form of pin holes or a material phenomenon that is not affected by its nanoporous structure.