Abstract:
The invention relates to a process for forming a lead-based ceramic oxide dielectric material comprising at least one pyrochlore crystalline phase, which process comprises the following steps: a) a step of depositing at least one amorphous layer of said lead-based ceramic oxide material on a substrate; and b) a crystallization annealing step carried out on said amorphous layer at a temperature not exceeding 550° C., by means of which a lead-based ceramic oxide dielectric material comprising at least one pyrochlore phase is obtained. Application to the fabrication of capacitors on integrated circuits.
Abstract:
The dielectric of a capacitor is formed by superposition of at least two thin layers made from the same metal oxide, respectively in crystalline and amorphous form and respectively presenting quadratic voltage coefficients of capacitance of opposite signs. The respective thicknesses da and dc of the amorphous and crystalline thin layers comply with the following general formulas: d a = ɛ 0 ɛ a C s 0 ( 1 1 - ( ɛ c ɛ a ) 2 γ a γ c ) and d c = ɛ 0 ɛ c C s 0 ( 1 1 - ( ɛ a ɛ c ) 2 γ c γ a ) in which ε0 corresponds to the electric constant, εc and εa correspond to the relative permittivity of the metal oxide respectively in crystalline form and in amorphous form, Cs0 corresponds to the total surface capacitance at zero field, and γc and γa correspond to the quadratic coefficient of capacitance with respect to the electric field of the metal oxide respectively in crystalline form and in amorphous form.
Abstract:
The invention relates to a process for forming a lead-based ceramic oxide dielectric material comprising at least one pyrochlore crystalline phase, which process comprises the following steps: a) a step of depositing at least one amorphous layer of said lead-based ceramic oxide material on a substrate; and b) a crystallization annealing step carried out on said amorphous layer at a temperature not exceeding 550° C., by means of which a lead-based ceramic oxide dielectric material comprising at least one pyrochlore phase is obtained. Application to the fabrication of capacitors on integrated circuits.
Abstract:
A device comprises at the input a first component (PA) having a first output impedance (Z1), at the output a second component (ANT) having a second input impedance (Z2), and an impedance-matching network between said first and second components. Because the first and/or the second impedance vary/varies, said impedance-matching network comprises a filter (Fadp), with an impedance that is matchable to the first and second impedances, located between said first and second components and comprising at least two acoustic wave coupled resonators. At least one of the resonators comprises a perovskite type material and means for applying a voltage to said resonator, which enable the permittivity and the impedance thereof to be varied.
Abstract:
An apparatus for converting vibratory mechanical energy into electrical energy includes a mobile mass, a support, first and second beams, the second being piezoelectric, and a junction element. The first beam extends longitudinally between the support and the mass, each of which has a beam end embedded therein. The second beam links the support and the mobile mass. Its elongation stiffness is lower than that of the first beam. The junction element extends between the beams. A first assembly, with a first bending stiffness, comprises the first beam, the second beam, and the junction element. A second assembly consists of the first assembly minus the second beam. Its bending stiffness is less than or equal to half of that of the first assembly.
Abstract:
This device includes a dielectric stack including at least one electret layer (2E), and two electrodes (16, 20) on two opposite faces (18, 22) of the stack. The electret is mineral. The device notably applies to the field of telecommunications.
Abstract:
The invention relates to a piezoelectric actuation structure including at least one strain gauge and at least one actuator produced from a stack on the surface of a substrate of at least one layer of piezoelectric material arranged between a bottom electrode layer and a top electrode layer, at least a portion of the stack forming the actuator being arranged above a cavity produced in the substrate, characterized in that the strain gauge is a piezoresistive gauge located in the top electrode layer and/or the bottom electrode layer, the layer or layers including electrode discontinuities making it possible to produce said piezoresistive gauge. The invention also relates to a method for producing such a structure.
Abstract:
The invention relates to a piezoelectric actuation structure including at least one strain gauge and at least one actuator produced from a stack on the surface of a substrate of at least one layer of piezoelectric material arranged between a bottom electrode layer and a top electrode layer, at least a portion of the stack forming the actuator being arranged above a cavity produced in the substrate, characterized in that the strain gauge is a piezoresistive gauge located in the top electrode layer and/or the bottom electrode layer, the layer or layers including electrode discontinuities making it possible to produce said piezoresistive gauge. The invention also relates to a method for producing such a structure.
Abstract:
The device for detecting elements in a fluidic medium comprises at least one acoustic resonator having a surface intended for fixing the elements. The resonator includes means for generating and measuring Lamb waves, favouring the generation of symmetrical Lamb waves. The device analyses the resonant frequency of the resonator in order to determine the variation in the resonant frequency of the symmetrical Lamb waves representative of the presence of the elements.
Abstract:
The capacitor is a thin-film capacitor comprising two metal electrodes separated by a dielectric. The dielectric is formed by superposition of at least two sub-layers of preferably perovskite-based dielectric material. Two adjacent superposed dielectric sub-layers are separated by an electrically insulated metal intermediate layer, for example made of platinum. Using very thin dielectric sub-layers, preferably with a thickness of less than 20 nm, separated from one another by metal intermediate layers enables the increase of the breakdown field and the reduction of the leakage currents linked to a reduction of the thickness of the dielectric to be transposed to the level of the capacitor, while preserving a reasonable working field.