The present invention relates to a method for fabricating an integrated electronic device with a microchannel, comprising the steps of: - Providing a homogeneous or heterogeneous substrate with one or more layers of material, respectively; - Forming at least one trench in the upper surface and through the upper layer using an etching process, particularly using a high aspect ratio etching process; - Sealing the trench by closing the opening of the trench on an upper surface of the upper layer.