AVS 50th International Symposium
    Semiconductors Tuesday Sessions
       Session SC-TuA

Paper SC-TuA5
Ab initio Prediction of the Gas-Phase Precursors for AlN Sublimation Growth@footnote 1@

Tuesday, November 4, 2003, 3:20 pm, Room 321/322

Session: Compound Semiconductor Growth and Processing
Presenter: Y. Li, North Carolina State University
Authors: Y. Li, North Carolina State University
D.W. Brenner, North Carolina State University
Correspondent: Click to Email
A free energy model using input from ab initio calculations is used to predict the concentration and saturation state (with respect to the growing crystal) of 16 Al@sub n@N@sub m@ species under conditions typical of AlN sublimation growth. The calculations predict that Al and N@sub 2@ are the dominant species, in agreement with available experimental measurements. However, our calculations predict that the N@sub 2@ molecule is undersaturated and therefore is not likely a growth precursor. Instead, our model predicts that Al@sub 2@N, Al@sub 3@N, and Al@sub 4@N, while in much smaller concentrations than N@sub 4@, are supersaturated and therefore are the source of nitrogen to the growing crystal. This prediction is in stark contrast to assumptions made in prior growth models, and may help explain why very small sticking coefficients had to be assumed for N@sub 2@ in prior modeling studies to match experimental growth rates. @FootnoteText@ @footnote 1@ Funded by the Office of Naval Research through MURI contract N00014-01-1-0302.