Micro silicon fuel cell, method of fabrication and self-powered semiconductor device integrating a micro fuel cell

摘要

A miniscule fuel cell is realized on a doped monocrystalline silicon subtrate.The microporous catalytic electrodes permeable to a gaseous fuel or an oxygen containing gas are constituted by a plurality of coplanar and parallel strips (3,4) of a catalytic metallic material electroplated or sputtered over an heterogeneous columnar skeleton structure of monocrystalline silicon (1,2) purposely formed by etching the silicon substrate to realize the plurality of parallel trenches (7,8) for ducting reagent and products of the electrode reactions to and from the microporous catalytic electrode formed thereon.The spaced parallel strips (3,4) constituting the microporous catalytic electrode permeable to gases are electrically connected one to the other by parallel strips (5,6) of conducting material alternate to the microporous strips of catalytic electrode material. The whole composite electrode structure of the half-cell is in electrical contact with the conducting substrate of monocrystalline silicon in correspondence of said strips of conducting material deposited over the crests of separation between adjacent parallel trenches etched in the silicon substrate, and optionally also in correspondence of the heterogeneous columnar skeleton of conducting monocrystalline silicon in case it is not completely removed by an eventual chemical and/or electrochemical final etching step after having deposited thereon the catalytic metal to form a self-sustaining microporous structure.Two half-cells thus formed on distinct silicon substrates are thereafter placed one against the other sandwiching, at least over the cell area, a thin film of permionic membrane substantially impermeable to fluids.