up a large surface area as an example each of these electrodes may have a surface area approximately ranging from 1 000 u03bcm 2 to 10 000 u03bcm 2 as a result the possible inaccuracies linked to the surface delimitation of the two regions of capacitor 45 are negligible to limit the number of manufacturing steps materials of baw resonator 25 are used to form capacitance 45 as an example electrodes 45 a and 47 c may be formed at the same time as electrodes 5 a and 5 c of the baw resonator for example with molybdenum similarly dielectric layer 47 b 49 b may be formed at the same time and with the same material as one of the following layers piezoelectric layer 5 b for example made of aluminum nitride a temperature compensation layer not shown for example made of silicon oxide currently arranged between piezoelectric layer 5 b and upper electrode 5 c or upper frequency adjustment layer 9 for example made of silicon nitride upper electrode 49 c requires a dedicated manufacturing step this electrode may for example be made of an alloy of copper and aluminum identical to that generally used to form contact pads not shown to improve the accuracy of the dielectric layer thinning down step it is desirable to provide on deposition of this layer the approximate capacitance that capacitor 45 must have for this purpose after the deposition of layer 47 b 49 b there is a measurement by ellipsometry of the thicknesses of the different dielectric layers forming the capacitor 45 according to an advantage of an embodiment of the present disclosure the provided method enables.