A method for manufacturing an integrated electronic device. The method includes providing an SOI substrate having a semiconductor substrate, an insulating layer on the semiconductor substrate, and a semiconductor starting layer on the insulating layer; epitaxially growing the starting layer to obtain a semiconductor active layer on the insulating layer for integrating components of the device, and forming at least one contact trench extending from an exposed surface of the starting layer to the semiconductor substrate before the step of epitaxially growing the starting layer, wherein each contact trench clears a corresponding portion of the starting layer, of the insulating layer and of the semiconductor substrate, the epitaxial growing being further applied to the cleared portions thereby at least partially filling the at least one contact trench with semiconductor material.