The photoluminescence and Raman scattering spectra of GaInP and AlInP grown by organometallic vapor‐phase epitaxy are measured to investigate the ordered and disordered crystalline states. It is found that ordered structure exists not only in the GaInP but also in the AlInP, and probably in the entire AlGaInP system, and that zinc doping over 1018cm−3makes it disordered. This disordering effect is attributed to the Zn diffusion in the GaInP epilayer during crystal growth which puts the once‐formed ordered atomic arrangement into a disordered state.