Trisdimethylaminoarsenic and phenylarsine have proven to be useful replacements for AsH3for growth of GaAs and AlGaAs by metalorganic molecular beam epitaxy. This paper will discuss the P analogs, namely, trisdimethylaminophosphorus (DMAP) and phenylphosphine (PhPH2), as well as trisdimethylaminoantimony (DMASb). All of these sources decomposed readily at the growth surface without precracking. InP surfaces were maintained with each source over a wide range, 375–525 °C, as were GaAs substrates over the range of 375–600 °C. Using DMAP, GaP was grown at rates up to 200 Å/min with slightly less carbon contamination than obtained with similar flows of PH3. When trimethylindium (TMI) or elemental In was introduced, however, neither the DMAP nor the PhPH2readily decomposed, thus leaving In droplets on the surface. InP was successfully grown by thermally cracking these compounds prior to injection to the chamber. The dependence of cracking efficiency and impurity uptake on cracker temperature will also be presented. DMASb was found to produce just the opposite effect of DMAP, apparently preventing the adsorption of triethylgallium, tri‐isobutylgallium, or trimethylaminealane on the surface for sufficient time to allow decomposition and hence growth to occur.