Improved performance of yttrium-doped Al2O3 as inter-poly dielectric for flash-memory applications

Abstract

Yttrium-doped Al 2O 3Y xAl yO) with different yttrium contents prepared by co-sputtering method is investigated as the inter-poly dielectric (IPD) for flash memory applications. A poor SiO 2-like interlayer formed at the IPD/Si interface is confirmed by X-ray photoelectron spectroscopy, and can be suppressed by Y doping through the transformation of silica into silicate. Compared with Al 2O 3 and Y 2O 3 films, the optimized Y xAl yO film shows lower interface-state density, lower bulk charge-trapping density, higher dielectric constant, and smaller gate leakage, due to the suppressed interlayer and good thermal property ascribed to appropriate Y and Al contents in the film. Therefore, the optimized Y xAl yO film is a promising candidate as the IPD for flash memory. © 2010 IEEE.