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Versum Lab Notes

Computational chemistry accelerates CVD or ALD precursors

Further shrinkage of electronic devices brings new challenges to quickly development of new materials and new thin film deposition processes. First, principles analysis of precursor chemistry and deposition mechanisms can significantly decrease experimental costs through initial virtual screening of potential precursors. Simultaneously, these studies can also improve the fundamental understanding of precursor stability and surface reactivity.

We have applied computational chemistry to the design of advanced organosilane and organometallic precursors. Below are modeling examples for organosilane and organometallic precursor development using computational chemistry.

Organosilane Precursors:

We applied Density Functional Theory (DFT) calculations to model chemisorption of organosilane precursors on silicon oxide. Figure 1 shows the various cycles involved in Atomic Layer Deposition (ALD) processes for an aminosilane precursor. Each of these cycles has been quantified in terms of thermochemistry and kinetics to understand the precursor properties and to optimize reactor operating conditions.

Organometallic Precursors:

DFT calculations were also employed to study ligand dissociation energies, decomposition mechanisms and surface reactions of various cobalt precursors on Cu, SiOH, and SiH terminated substrates. Cobalt precursors considered in this study include cobalt amides, cobalt imidazolyls and cobalt carbonyls with cyclopentadienyl, allyl and alkyne ligands. The study provided insight on the selectivity of Co deposition on different substrates and allowed a more systematic approach for the selection of new ALD Co precursors. Figure 2 shows how first-principles calculations were used to quantify the thermodynamics of a precursor reaction with two different substrates.



Agnes Derecskei is a Research Associate and has been with the company since 2010. She graduated from the University of Texas at Arlington with a Ph.D. in Mathematical Sciences/Chemistry and the Lajos Kossuth University in Debrecen, Hungary with a Ph.D. in Theoretical Physics.




Andrew J. Adamczyk is a Sr. Principal Engineer and has been with the company for five years providing modeling support for product and process development. He graduated from Northwestern with a Ph.D. in Chemical Engineering and was a postdoctoral fellow at MIT and USC, where he worked with Nobel Laureate Prof. Arieh Warshel.




Sergei Ivanov is a Research Associate and has been with the company for over 15 years. He graduated from the Institute of General and Inorganic Chemistry of the Russian Academy of Sciences with a Ph.D. in Inorganic Chemistry.