A solid oxide fuel cell structure obtainable by selective electrochemical processing, comprising an electrolyte membrane (4) formed by a thin film more than 50nm but less than l0[mu]m thick, covering a supporting structure (1) made of a bulk substrate, the supporting structure having at least one l00[mu]m to 100mm wide opening that is covered by the electrolyte membrane (4) . A metallic grid (9) is applied over the electrolyte membrane (4) and serves at the same time as structural element to support the membrane and as current collector. The metallic grid (9) has gridlines that are higher than the membrane thickness and whose height to width ratio is larger than 0.5, and a mesh size about 10 to 1000 times smaller than the width of said opening. The metallic grid (9) can be applied on top of a patterned metallic sub-layer structure (7,7a) arranged for supplying a fine distribution of current and increasing the density of electrolyte-electrode boundaries exposed to the fluid. The structure is useful for current generation and as a gas sensor.