Zinc incorporation into InP grown by atmospheric pressure metalorganic vapor phase epitaxy has been studied systematically as a function of Zn source flow rate, substrate orientation, and growth temperature. Within the growth conditions for device quality layers, a Zn saturation level exists which varies with substrate orientation. The incorporation kinetics is analyzed using a surface adsorption‐trapping model. We demonstrate that the Langmuir state of adsorption–desorption process is not established during growth due to the interruption of the surface processes by layer growth. The existence of a saturation level at a given growth condition indicates that Zn atoms incorporate at defect sites instead of the normal growth sites for In. Two parameters are used to characterize the properties of the surface defect, i.e., the capture cross section and the time of desorption for Zn atoms. The implication of these parameters and their substrate orientation and growth temperature dependencies are discussed. ©1996 American Institute of Physics.