Patent ID: 7927888

Claim:
A method to fabricate a microelectronic device provided with at least one circuit to detect biological elements, comprising the steps of: a) forming, on a substrate, a plurality of transistors each comprising at least one gate formed of at least one layer in at least one gate material on at least one layer of gate dielectric, said gate resting on a channel region, depositing at least one layer in at least one insulating material coating said transistors, forming one or more holes in said layer of insulating material, so as to expose the upper face of the respective gate of the so-called “first-type” transistors among said transistors, whilst one or more other so-called “second-type” transistors among said transistors are coated with insulating material, filling the holes with gate material chosen so that it can be etched selectively with respect to the insulating material, the filling allowing the formation of blocks in said gate material respectively resting on the upper face of the gates of the first-type transistors, b) removing said blocks in said gate material, and removing at least in part the respective gate of the first-type transistors, whilst the respective gate of one or more other transistors called “second-type transistors”, amongst said transistors, is protected, c) binding biological receptors on a surface located facing the channel region of the first-type transistors, these receptors intended to receive one or more biological markers.