In this paper was presented the research results of the dependence of the InGaAs surface layer thickness on the process of Zn diffusion into InGaAs/InP heterostructures from a diethylzink source. One-dimensional distribution profiles of electrically active dopants were obtained by electrochemical volt-capacitive profiling. The influence of technological parameters (process time, temperature, and pressure in the reactor) on the hole concentration and the depth of the p-type dopant was studied. The principal possibility of simultaneously forming a highly doped InGaAs:Zn layer has been experimentally shown due to the higher Zn solubility limit in InGaAs compared to InP and to implement a two-stage p-type dopant profile in one Zn diffusion process by controlling the thickness of the InGaAs surface layer.