Self-limiting growth of ZnS on Si substrates at a growth rate of 0.7 monolayers per operating cycle by atomic layer epitaxy using MOCVD

ZnS films were grown on (100) Si substrates by atomic layer epitaxy (ALE) using a metal-organic chemical vapor deposition system. We studied the growth rate as a function of the substrate temperature and the flow rates of DMZn and H2S. The growth rate was kept constant at 0.7 monolayers per cycle and was independent of substrate temperature in the range 125-225°C, and of the mole fractions of both DMZn and H2S. Although the fractional ALE growth does not produce a two-dimensional surface, SEM micrographs show smooth ZnS films with the atomic ratio of S:Zn very close to unity.