Final PhD Seminar - Rory J. Vander Valk  

The Department of Chemistry and Biochemistry Rose Mercadante Seminar Series is pleased to present the final PhD seminar of Rory J. Vander Valk, entitled "Determination of Distribution and Electronic Activity of Principal Defects in Arsenic Doped Silicon."

The seminar will be presented at 5:45 p.m. on Tuesday March 14, 2017 in the Helen Lerner Amphitheater, Science and Technology Center, McNulty Hall, Seton Hall University. The university community is welcome to attend.

The next generation of semiconductor device electronics, especially as pertains to nanostructured architectures, will place increasing importance on the control of the structural and dynamical properties of implanted defects in the semiconductor bulk matrix1. Currently proposed architectures for next generation silicon semiconductor devices require that metal-oxide semiconductor junctions be less than 5 nm in depth. This severe constraint increases the probability that dopants and defects will diffuse toward each other in such a confined space resulting in deactivation. This is observed experimentally in annealing processes following ion implantation of arsenic into crystalline silicon where the remaining electronically active fraction of arsenic is observed to be 30-42% of the retained dose.

Here we examine the electrical activity and relative formation energy of defect structures in silicon semiconductors doped with Arsenic using planewave density functional theory calculations. These values are correlated with Maxwell-Boltzmann distributions of relative population ratios of defect states to determine the expected properties at thermodynamic equilibrium. These results will permit prediction of the number of carrier donating and trapping sites as a comparison with current experimental findings of active carriers after processing. In addition, calculation of relative diffusion rates of defects will allow prediction of preferred defect clusters formed at high temperatures. This additional refinement is expected to account for potential meta-stable states formed in rapid thermal processes such as laser annealing.

Rory J. Vender Valk is a native of New Jersey. He holds a BA in Chemistry from Caldwell University and a MS in Chemistry from Seton Hall. He performed his research under the mentorship of Professors Stephen P. Kelty of the Department of Chemistry and M. Alper Sahiner of the Department of Physics.