A process for manufacturing an optoelectronic device having a diode matrix with semiconductor stacks involves providing a growth substrate having a support substrate coated with a nucleation layer defining a nucleation surface. A dielectric layer is deposited on the nucleation surface. A plurality of through-holes, extending to the nucleation surface, are formed in the dielectric layer. The nucleation layer, located in the through-holes, is etched to free up an upper surface of the support surface and expose a lateral surface of the nucleation layer forming a lateral nucleation surface. A dielectric region is formed extending in the support substrate such that, during a subsequent epitaxial growth stage, each first doped portion is formed especially from the lateral nucleation surface. In the through-holes and from the nucleation surface, the semiconductor stacks are epitaxially grown such that at least the first doped portions and active zones thereof are located in the through-holes.