| Autor: |
Cassé, Mikaël, Thevenod, Laurent, Guillaumot, Bernard, Tosti, Lucie, Martin, François, Mitard, Jérôme, Weber, Olivier, Andrieu, François, Ernst, Thomas, Reimbold, Gilles, Billon, Thierry, Mouis, Mireille, Boulanger, Fabien |
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| Zdroj: |
IEEE Transactions on Electron Devices; Apr2006, Vol. 53 Issue 4, p759-768, 10p, 1 Diagram, 1 Chart, 16 Graphs |
| Abstrakt: |
Electron and hole mobility in HfO2/metal gate MOSFETs is deeply studied through low-temperature measurements down to 4.2 K. Original technological splits allow the decorrelation of the different scattering mechanisms. It is found that even when charge trapping is negligible, strong remote coulomb scattering (RCS) due to fixed charges or dipoles causes most of the mobility degradation. The effective charges are found to be located in the HfO2 near the SiO2 interface within 2 nm. Experimental results are well reproduced by RCS calculation using 7 × 1013 cm-2 fixed charges at the HfO2/SiO2 interface. We also discuss the role of remote phonon scattering in such gate stacks. Interactions with surface soft-optical phonon of HfO2 are clearly evidenced for a metal gate but remain of second order. All these remote interactions are significant for an interfacial oxide thickness up to 2 nm, over which, these are negligible. Finally, the metal gate (TIN) itself induces a modified surface-roughness term that impacts the low to high effective field mobility even for the SiO2 gate dielectric references. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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