Continued scaling of microelectronic devices has driven the change from SiO2 to alternative, Hf-based, high-k gate dielectric materials in recent years. This materials change has enabled device performance scaling without the gate leakage current becoming unacceptably high. The change from doped poly-Si to metal(s) as the gate electrode material also occurred simultaneously with the introduction of high-k materials, as the resulting high-k /metal gate (HKMG) device can effectively overcome depletion effects in poly-Si gate devices. Processing of the metal gate stack is a challenging task in terms of meeting requirements in effective work function for both nMOS and pMOS, as well as enabling low resistivity gate/contact metal fill. The introduction of 3D device structures such as FinFETs serves as an inflection point for novel materials and the transition from PVD to ALD processes.

Atomic layer deposition (ALD) will be used in multiple areas of the 22nm logic process flow despite initial concerns about the technology's viability for high-volume manufacturing. Each application space creates a unique need for manufacturing equipment configuration and technology variations - from single-wafer ALD systems for extremely tight process control, batch ALD systems for low COO operation, to mini-batch systems for a meld of COO and process control for multi-layer applications. Selection of the appropriate manufacturing toolset is as critical to eventual technology adoption as the process itself, and final implementation will require the correct toolsets to ensure that the ALD films can be deposited in a cost efficient manner.

Surface molecular contamination of gate dielectrics in metal oxide semiconductor structures is a problem affecting the performance of integrated circuits. The impact depends strongly on the nature of the interactions between the contaminants and the dielectric surfaces. The mechanism of interactions of moisture and isopropyl alcohol (IPA) with SiO2 and ZrO2 films was studied using isotope labeling with deuterium oxide (D2O). The results revealed that H2O adsorbs in a random multilayer configuration with three distinct types of interactions (hydroxylation of oxide in the first layer, MOH-H2O interactions in the second layer, and nondissociative H2O-H2O interactions in the higher layers). On the basis of these findings, a multilayer multicomponent adsorption/desorption model was developed that agrees well with the experimental data. The adsorption of IPA also follows multilayer dynamics. The interaction with the bare dielectric surface is nondissociative and relatively weak. However, IPA chemisorbs on a hydroxylated oxide. The isotope labeling studies revealed an exchange mechanism in which IPA undergoes an esterification reaction with chemisorbed H2O.