Investigation of hafnium-aluminate alloys in view of integration as interpoly dielectrics of future Flash memories

In this paper, we evaluate the potentialities of hafnium-aluminates (HfAlO) materials as possible candidates for the interpoly dielectrics of future Flash memory devices. HfAlO layers of different thicknesses and compositions are integrated in single-layers and in Oxide/HfAlO/Oxide (OHO) triple-laye...

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Bibliographic Details
Published in:	Solid-state electronics Vol. 51; no. 11; pp. 1540 - 1546
Main Authors:	Molas, Gabriel, Bocquet, Marc, Buckley, Julien, Grampeix, Helen, Gély, Marc, Colonna, Jean-Philippe, Licitra, Christophe, Rochat, Névine, Veyront, Thomas, Garros, Xavier, Martin, François, Brianceau, Pierre, Vidal, Vincent, Bongiorno, Cosimo, Lombardo, Salvatore, Salvo, Barbara De, Deleonibus, Simon
Format:	Journal Article Conference Proceeding
Language:	English
Published:	Oxford Elsevier Ltd 01-11-2007 Elsevier Science Elsevier
Subjects:	Applied sciences Design. Technologies. Operation analysis. Testing Electronics Engineering Sciences Exact sciences and technology Hafnium-aluminate HfAlO High-k Integrated circuits Integrated circuits by function (including memories and processors) Interpoly dielectrics Magnetic and optical mass memories Micro and nanotechnologies Microelectronics Non-volatile memories Poole–Frenkel Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices Storage and reproduction of information Hafnium-aluminate Interpoly dielectrics HfAlO High-k Poole–Frenkel Non-volatile memories Memory devices HfA1O Oxide layer Multiple layer Poole-Frenkel Low voltage Electric field Interpoly dielectric High voltage Flash memory Non volatile memory Integrated circuit Hafnium Leakage current High k dielectric Poole Frenkel effect Activation energy
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Summary:	In this paper, we evaluate the potentialities of hafnium-aluminates (HfAlO) materials as possible candidates for the interpoly dielectrics of future Flash memory devices. HfAlO layers of different thicknesses and compositions are integrated in single-layers and in Oxide/HfAlO/Oxide (OHO) triple-layer stacks, and analyzed in terms of coupling and insulating capabilities. We demonstrate that increasing the Hf content allows reducing the leakage current at high voltages but it results in a stronger leakage current at low voltages. We also show that once normalized in electric fields, the leakage current characteristics are independent of the high-k thickness. The electron conduction modes in these materials, at different temperatures, are also investigated. The activation energy increases with the Hf concentration in the HfAlO alloy, resulting in a higher leakage current at elevated temperatures. Finally, it is demonstrated that the conduction in triple-layer stacks is limited by a Poole–Frenkel conduction in the high-k layers, while the trap contribution in the case of single-layers becomes dominant when the HfAlO layer is thicker than 8 nm.
ISSN:	0038-1101 1879-2405
DOI:	10.1016/j.sse.2007.09.020