Si delta‐doped layers of GaAs were grown by low pressure metal organic vapor phase epitaxy (LP‐MOVPE). The results showed that, in LP‐MOVPE, growth rate plays a crucial role in confinement of dopants and growth temperature has only a secondary effect. Effects of purge time, doping temperature, and doping period on sheet carrier concentration of delta‐doped layers were studied. The effect of growth rate on confinement of dopants was discussed.