Mécanismes de croissance épitaxiale en phase vapeur aux organo-métalliques de InP

We have studied the mechanisms of epitaxial growth in a horizontal low pressure MOVPE reactor designed for the growth of binary, ternary and quaternary layers and heterostructures based on InP. The intermediate range of temperatures studied (550 o C-620 o C) allowed us to interpret the growth rate in terms of a transition between two processes: adsorption/reaction of reactive species and mass transport of element III species. Our results indicate that the low pressure MOVPE growth of InP (using trimethylindium and phosphine) cannot be explained in terms of a homogeneous adduct as has been suggested in the literature. On the contrary our results suggest an Eley-Rideal type mechanism, based on the absorption and reaction of In species, assisted by phosphorus containing molecules already present at the surface. We have measured certain threshold kinetic parameters which separate the mass transport controlled regime from that controlled by the kinetics of surface reactions. Our results show that at constant temperature the V-hydride partial pressure which limits these two regimes, (P PH3 ) th , increases with the partial pressure of the element III species, while keeping constant the V/III ratio at (V/III) th