Highly conformal film growth by chemical vapor deposition. II. Conformality enhancement through growth inhibition

Abstract

The authors present a novel strategy for enhancing conformality in chemical vapor deposition (CVD) based on the concept of growth inhibition. In Part I, they showed how surface site blocking was responsible for the increase in conformality observed at higher pressures in high vapor pressure precursors. In this work, they apply this concept to enhance conformality by considering a secondary species that acts as an inhibitor of the precursor. The experimental results obtained for the growth of TiB2 from Ti(BH4)3dme (dme=dimethoxyethane), with dme acting as the growth inhibitor, agree well with the models, based on a first order adsorption/desorption kinetics, and show how this strategy greatly enhances the conformality of nonconformal precursors. Finally, they show how multiple surface mechanisms including surface site blocking, associative desorption, long surface residence time of by-products, or coadsorption of two reactants can induce growth inhibition. Consequently, this strategy can be potentially applied to many existing CVD systems, provided suitable molecular inhibitors are identified.