Uwe R. Kortshagen, Associate Fellow

Highly Realistic Modeling of Low-Pressure Processing Plasmas

These researchers studied new approaches for fast and realistic modeling of low-pressure processing plasmas. One focus was the accurate prediction of the electron energy distribution function, which is essential for the correct prediction of atomic processes and plasma-chemical rates in lowpressure plasmas. Approaches relying on the numerical solution of the Boltzmann equation frequently must use a number of approximations and are limited in their range of validity. The researchers used a highly realistic Monte Carlo approach based of first principles to accurately determine the electron energy distribution function in a low-pressure plasma. The results determined by the researchers provided new insight into the physics of electron transport processes, both in configuration and in energy space. The benchmark calculations performed also served as reference for comparisons with less general methods based on the approximate numerical solution of the Boltzmann equation.

A second focus of this research was the study of the chemical nucleation of nanometer-sized particles in plasmas. Here the researchers focused on the chemical nucleation of clusters in low-pressure silane plasmas. The formation of particles in low pressure plasmas was of high interest, both from the viewpoint of synthesis of new nanostructured materials and as it related to particle contamination in low pressure plasma processing of microelectronic devices. The formation of initial clusters should be understood as a sequence of reversible chemical reactions. This project continued to consider the development of a chemical reaction mechanism describing chemical clustering in lowpressure silane plasmas. The mechanism included neutral and ionic chemistries, particle coagulation, and transport modeling using aerosol dynamic methods.

Research Group

Upendra Bhandarkar, Graduate Student Researcher
Chenbin He, Graduate Student Researcher
Vitaly A. Schweigert, Research Associate
Eli Kostadinova Stoykova, Research Associate
Mark Swihart, Faculty Collaborator
Peng Zhang, Graduate Student Researcher