Susceptibility of SiO2, ZrO2, and HfO2dielectrics to moisture contamination

Raghu, P.; Yim, C. T.; Shadman, Farhang; Shero, Eric

doi:10.1002/aic.10148

Cited by 16 publications

(26 citation statements)

References 23 publications

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“…For completeness, we also determine the FEPs for two other SL product models, namely 12O:24F 11 and at 300 • C (573 K). 11 Comparing to Figure 6 this is true for partial surface O removal (8O:16F) where self-limiting is preferred up to 618 K for 3 4 of surface O removal and up to 657 K for 1 2 of surface O removal. The same analysis holds for ZrO 2 .…”

Section: Reaction Free Energy Profilesmentioning

confidence: 75%

Self-Limiting Temperature Window for Thermal Atomic Layer Etching of HfO₂ and ZrO₂ Based on the Atomic-Scale Mechanism

et al. 2020

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HfO 2 and ZrO 2 are two high-k materials that are important in the down-scaling of semiconductor devices. Atomic level control of material processing is required for fabrication of thin films of these materials at nanoscale device sizes. Thermal Atomic Layer Etch (ALE) of metal oxides, in which up to one monolayer of the material can be removed, can be achieved by sequential self-limiting fluorination and ligand-exchange reactions at elevated temperatures. However, to date a detailed atomistic understanding of the mechanism of thermal ALE of these technologically important oxides is lacking.In this paper, we investigate the hydrogen fluoride pulse in the first step in the thermal ALE process of HfO 2 and ZrO 2 using first principles simulations.We introduce Natarajan-Elliott analysis, a thermodynamic methodology, to compare reaction models representing the self-limiting (SL) and continuous spontaneous etch (SE) processes taking place during an ALE pulse. Applying this method to the first HF pulse on HfO 2 and ZrO 2 we found that thermodynamic barriers impeding continuous etch are present at ALE relevant temperatures. We performed explicit HF adsorption calculations on the oxide surfaces to understand the mechanistic details of the HF pulse. A HF molecule adsorbs dissociatively on both oxides by forming metal-F and O-H bonds. HF coverages ranging from 1.0 ± 0.3 to 17.0 ± 0.3 HF/nm 2 are investigated and a mixture of molecularly and dissociatively adsorbed HF molecules is present at higher coverages. Theoretical etch rates of -0.61 ± 0.02 Å /cycle for HfO 2 and -0.57 ± 0.02 Å /cycle ZrO 2 were calculated using maximum coverages of 7.0 ± 0.3 and 6.5 ± 0.3 M-F bonds/nm 2 respectively (M = Hf, Zr).

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Section: Reaction Free Energy Profilesmentioning

confidence: 75%

Self-Limiting Temperature Window for Thermal Atomic Layer Etching of HfO₂ and ZrO₂ Based on the Atomic-Scale Mechanism

et al. 2020

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“…This can be understood from the fact that the energy required to remove the water molecules that are far from SiO 2 surface is lower than the ones which are in close contact with SiO 2 . In fact, Raghu et al [24] have estimated desorption activation energies for water molecules for SiO 2 surface for these two regions to be 13 kJ/mol and 19 kJ/mol, respectively. It is also possible that in low RH regime, water has ice like structure initially close to the surface, and progressively changing to bulk liquid like configuration of water molecules as humidity increases [25].…”

Section: Resultsmentioning

confidence: 97%

“…However in both the studies, no experimental evidence was provided to support the argument based on MC surface. Further, Raghu et al [24], have reported the desorption kinetics of H 2 O molecules from native grown SiO 2 on Si surface using electron impact mass spectrometer. They also noticed an exponential decay during desorption and explained it on the basis of multilayer adsorption model.…”

Section: Methodsmentioning

confidence: 98%

Role of surface morphology on desorption kinetics of water molecules from uncoated silicon microcantilever

Raghuramaiah

Prabakar

Sundari

et al. 2016

Sensors and Actuators B: Chemical

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“…There has been a considerable amount of research on the interactions of contaminants with high‐k dielectrics12–14; however, the mechanism of contaminant adsorption and diffusion in low‐k materials and the effect of porosity and pore structure on the mobility of contaminants have not been adequately studied and characterized. This information is critical because these materials are exposed to a wide variety of conditions during fabrication processes.…”

Section: Introductionmentioning

confidence: 99%

Removal of moisture contamination from porous polymeric low‐k dielectric films

et al. 2006

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Susceptibility of SiO₂, ZrO₂, and HfO₂dielectrics to moisture contamination

Cited by 16 publications

References 23 publications

Self-Limiting Temperature Window for Thermal Atomic Layer Etching of HfO₂ and ZrO₂ Based on the Atomic-Scale Mechanism

Self-Limiting Temperature Window for Thermal Atomic Layer Etching of HfO₂ and ZrO₂ Based on the Atomic-Scale Mechanism

Role of surface morphology on desorption kinetics of water molecules from uncoated silicon microcantilever

Removal of moisture contamination from porous polymeric low‐k dielectric films

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Susceptibility of SiO2, ZrO2, and HfO2dielectrics to moisture contamination

Cited by 16 publications

References 23 publications

Self-Limiting Temperature Window for Thermal Atomic Layer Etching of HfO2 and ZrO2 Based on the Atomic-Scale Mechanism

Self-Limiting Temperature Window for Thermal Atomic Layer Etching of HfO2 and ZrO2 Based on the Atomic-Scale Mechanism

Role of surface morphology on desorption kinetics of water molecules from uncoated silicon microcantilever

Removal of moisture contamination from porous polymeric low‐k dielectric films

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Product

Resources

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Susceptibility of SiO₂, ZrO₂, and HfO₂dielectrics to moisture contamination

Self-Limiting Temperature Window for Thermal Atomic Layer Etching of HfO₂ and ZrO₂ Based on the Atomic-Scale Mechanism

Self-Limiting Temperature Window for Thermal Atomic Layer Etching of HfO₂ and ZrO₂ Based on the Atomic-Scale Mechanism