Phosphorus-containing diamond films were deposited on Si(100) by hot-f
ilament CVD using a Ta filament and mixtures of hydrogen, methane and
phosphine. The phosphorus concentration in the gas phase was varied be
tween 330 and 5280 ppm PH3/CH4. The P additions led to important modif
ications in the diamond morphology, growth rate, growth orientation, f
ilm quality and homogeneity. These modifications were similar to those
which are observed in a growth environment leading away from optimal
growth conditions for diamond. The P additions, however, seemed to inf
luence the growth kinetics due primarily to surface reactions rather t
han to changes in the gas activation (i.e. atomic hydrogen and carbon
growth species). A comparison between experimental results and thermod
ynamic calculations suggested that methinophosphide (HCP) - an unstabl
e and highly reactive phosphorus species - is probably responsible for
the deleterious P influences. Qualitative secondary-ion mass spectrom
etry measurements showed the presence of P in all diamond films prepar
ed with PH3 added to the reaction gases.