Electrical Characterization of Aluminum-Oxynitride Stacked Gate Dielectrics Prepared by a Layer-by-Layer Process of Chemical Vapor Deposition and Rapid Thermal Nitridation

Hideki MURAKAMI  Wataru MIZUBAYASHI  Hirokazu YOKOI  Atsushi SUYAMA  Seiichi MIYAZAKI 

Publication
IEICE TRANSACTIONS on Electronics  Vol.E88-C  No.4  pp.640-645
Publication Date: 2005/04/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Fundamental and Application of Advanced Semiconductor Devices)
Category: Si Devices and Processes
Keyword: 
high-k dielectrics,  aluminum oxide,  reliability,  MISFET, 

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Summary: 
We investigated the use of AlOx:N/SiNy stacked gate dielectric as an alternate gate dielectric, which were prepared by alternately repeating sub-nanometer deposition of Al2O3 from an alkylamine-stabilized AlH3 + N2O gas mixture and rapid thermal nitridation in NH3. The negative fix charges, being characteristics of almina, were as many as 3.91012 cm-2 in the effective net charge density. The effective dielectric constant and the breakdown field were 8.9 and 8 MV/cm, respectively, being almost the same as pure Al2O3. And we have demonstrated that the leakage current through the AlOx:N/SiNy stacked gate dielectric with a capacitance equivalent thickness (CET) of 1.9 nm is about two orders of magnitude less than that of thermally-grown SiO2. Also, we have confirmed the dielectric degradation similar to the stress-induced leakage current (SILC) mode and subsequent soft breakdown (SBD) reported in ultrathin SiO2 under constant current stress and a good dielectric reliability comparable to thermally-grown ultrahin SiO2. From the analysis of n+poly-Si gate metal-insulator-semiconductor field effect transistor (MISFET) performance, remote coulomb scattering due to changes in the gate dielectric plays an important role on the mobility degradation of MISFET with AlON/SiON gate stack.