Study of atomic layer epitaxy of zinc oxide by in-situ quartz crystal microgravimetry

The deposition of ZnO thin films by atomic layer epitaxy (ALE) from diethyl zinc and water precursors is studied for the first rime by an in-situ quart z crystal microbalance technique. Quantitative measurement of the growth wi th a resolution down to the monolayer level is demonstrated. Influence of t emperature, pulse lengths and substrate characteristics has been studied. T he site saturation regime (ALE window) is between 100 degrees C and 160 deg rees C and corresponds to the growth of one (100) monolayer with possible e ffects of roughness and surface reconstruction. Effect of nucleation and co alescence has been clearly evidenced both on foreign substrates and more su rprisingly on ZnO substrates depending of the duration of the rest period. The analysis of the mass variation during individual cycles raises some que stions about the growth mechanism. (C) 2000 Published by Elsevier Science B .V. All rights reserved.