J. Phys. IV France 02 (1991) C2-201-C2-208
DEPOSITION OF CUBIC BORON MONOPHOSPHIDE FROM BBr3 AND PBr3 : A REACTION MECHANISME.M. KELDER, P.J. VAN DER PUT, J.G.M. BECHT and J. SCHOONMAN
Laboratory for Inorganic Chemistry, Delft University of Technology, Julianalaan 136, NL-2628 BL Delft, The Netherlands
The CVD growth kinetics of polycrystalline cubic BP at atmospheric pressure were studied for the BBr3-PBr3-H2 system using in situ thermogravimetry. In the temperature range 1050-1350 K the deposition obeys Langmuir-Hinshelwood kinetics having two different activation enthalpies. These are consistent with different rate limiting reactions in two temperature regimes. At low temperature PBr3 is the main adsorbed species and the activation enthalpy is 224 kJ/mole due to substrate-phosphorus bond breaking of chemisorbed phosphorus species. At higher temperatures when the main adsorbed species is P2 the reaction is determined by an activation enthalpy of 247 kJ/mole due to P=P bond breaking of the P2 species at the surface. The order in H2 decreases with temperature from 1/2 at low temperature to zero at high temperature. The effect of the gas phase hydrogen partial pressure on the growth kinetics is explained by a higher affinity of H2 towards the substrate-phosphorus bond than towards the P=P bond of adsorbed P2.
© EDP Sciences 1991