Abstract: This invention proposes the use of a thermodynamic screen placed under the electronic devices whose excess noise is to be reduced in order to block the transverse currents between said devices and subjacent layers that are responsible for the aforementioned excess noise. For epitaxial layers as those used in Microelectronics, the barrier layer (2) with an opposed doping to the epilayer supporting the devices (4), and the non-doped separating layer (3) form the thermodynamic screen which, embedded between the epilayer (4) and the substrate (1), reduces the aforementioned transverse currents and thus the excess noise of the devices on the epilayer (4) when they are biased.