Nanoindentation Investigation of HfO2 and Al2O3 Films Grown by Atomic Layer Deposition

Abstract

The challenges of reducing gate leakage current and dielectric breakdown beyond the 45 nm technology node have shifted engineers’ attention from the traditional and proven dielectric to materials of higher dielectric constant also known as high- materials such as hafnium oxide and aluminum oxide . These high- materials are projected to replace silicon oxide . In order to address the complex process integration and reliability issues, it is important to investigate the mechanical properties of these dielectric materials in addition to their electrical properties. In this study, and have been fabricated using atomic layer deposition (ALD) on (100) p-type Si wafers. Using nanoindentation and the continuous stiffness method, we report the elastomechanical properties of and on Si. ALD thin films were measured to have a hardness of and a modulus of , whereas the ALD thin films have a hardness of and a modulus of . The two materials are also distinguished by very different interface properties. forms a hafnium silicate interlayer, which influences its nanoindentation properties close to the interface with the Si substrate, while does not exhibit any interlayer.