Design of precursors for CVD and ALD

INOR 348

Roy G. Gordon, gordon@chemistry.harvard.edu, Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA 02138
Selection of an appropriate precursor is a critical first step in developing CVD and ALD processes. Certain precursor properties are common to both CVD and ALD: sufficient vapor pressure at a temperature at which decomposition is negligible, deposition reactions that produce a pure product at a high enough rate, a synthesis procedure that produces a sufficiently pure product at a cost that is low enough for applications, and long shelf life. For ALD, the deposition reactions take place on the surface of the material being formed. In CVD, gas phase reactions as well as surface reactions, may take place. Several other precursor properties are desirable: low melting points (preferably below room temperature), low toxicity, and non-corrosive precursors and reaction byproducts.

Case studies of precursor design will be discussed: ALD of high-k dielectrics (hafnium, zirconium and multicomponent lanthanides), and CVD and ALD of materials for microelectronic interconnects (copper, cobalt and ruthenium).