Electron beam assisted physical vapor deposition (EBPVD) is widely used in a number of vacuum material processing applications for deposition of thin films of metals. The properties of these thin films including thickness uniformity, growth rates and other material properties are dependent, to a great extent, on the geometric configuration of the deposition source and electron gun power. A complete understanding of the deposition process requires the ability to accurately simulate the vapor flow that varies from highly collisional in regions near the source to being free-molecular near the substrate location. The direct simulation Monte Carlo technique, which is by far the most powerful technique to simulate such flows rapidly expanding into vacuum, requires an accurate molecular model for the interaction between the metal vapor atoms. A molecular model has been formulated [1] for the interaction of Cu atoms and validated with experimental data for electron-beam deposition of copper. The main goal of this work is to formulate molecular models for common metal vapors including Gold, Titanium, Nickel, and Aluminium and validate them with experimental data[2,3] for thin-film growth rates at various evaporation rates. The ability to accurately model deposition processes of thin films of metals would greatly assist in the design and control of such vacuum deposition systems and processes.

 

 

[1] A. Venkattraman and A.A. Alexeenko, “DSMC Modeling of E-beam Metal Deposition”, J. Vac. Sci. & Tech. A, July 2010 (accepted).

[2] D. Chaleix, P. Choquet, A. Bessaudou, L. Frugier, and J. Machet, “A spatial distribution study of a beam vapour emitted by electron-beam-heated evaporation sources”, J. Phys. D: Appl. Phys. 29(1996) 218-224.

[3] K.B. Thakur and G.K.Sahu, “Spatial distribution of copper vapour flux during strip electron beam vaporation”, J. Phys. D: Appl. Phys. 35(2002) 1812-1820.