Abstract: The invention relates to a resonator operating with bulk acoustic waves (BAW resonator, BAW=Bulk Acoustic Wave) and band-pass filters constructed of such resonators. To increase the edge steepness of the transmission band of a BAW band-pass filter, the invention proposes reducing the effective coupling of a BAW resonator by using the connection in parallel of a BAW resonator and a capacitor instead of only one resonator. In addition, to increase the edge steepness of the transmission band, the use of a connection of coupled BAW resonators in the serial branch of a filter circuit with another resonator or resonator stack in the parallel branch of the filter circuit is proposed, the additional resonator or resonator stack being connected to the center electrode of the resonator stack specified initially.

Abstract: An acoustic wave transducer includes an acoustic track having electrode fingers for different electrodes. The electrode fingers engage to form exciting finger pairs. The acoustic track also includes marginal areas and an excitation area. The electrode fingers engage in the excitation area. The marginal areas and the excitation area are located along a transverse direction of the acoustic wave transducer. A longitudinal phase speed of an acoustic wave in the acoustic track is less in a marginal area than in the excitation area, and the acoustic wave is excitable and has a transversal basic mode. The following applies in the transversal basic mode for a wave number ky: (ky)2>0 in a marginal area, and (ky)2<0 in an exterior area outside the acoustic track. ky is smaller in the excitation area than in the marginal areas and in the exterior area.

Abstract: Proposed is a resonator which works with bulk acoustic waves and is based on a layer structure known in the art, which is arranged over a substrate. According to the invention, the total surface of the layer structure, including all resonators contained therein, is covered with a dielectric layer and a metal layer which together form an acoustic mirror, a low-k dielectric being used for the dielectric layer. The total-surface mirror offers broadband functionality over a suitable frequency range. The dielectric contained within the mirror acts as a sealing protective layer for the resonator or resonators.

Abstract: Spacer structures of field effect transistor structures are enhanced at least in sections with immobile charge carriers. The charge accumulated in the spacer structures induces an enhancement zone of mobile charge carriers in the underlying semiconductor substrate. The enhancement zone reduces the resistance of a channel coupling between the respective source/drain region and a channel region of the respective field effect transistor structure, wherein the channel region being controlled by a potential of a gate electrode. Source/drain regions drawn back from the gate electrode of the field effect transistor structure reduce an overlap capacitance between the gate electrode and the respective source/drain regions. A method for fabricating transistor arrangements having n-FETs and p-FETs with enhanced spacer structures.

Abstract: The present invention relates to a method for fabricating a semiconductor device. In order to provide for a high carrier mobility in an active region of the device, germanium atoms are implanted into a surface of a semiconductor substrate such that a germanium-containing layer inside the semiconductor substrate is formed. Then, the surface of the semiconductor surface is oxidized down to and including the upper part of the germanium-containing layer, thereby pushing the implanted germanium atoms from the surface down into the semiconductor substrate and thereby enhancing the germanium concentration inside the remaining germanium-containing layer and forming a layer with enhanced germanium concentration inside the semiconductor substrate. The fabrication of the semiconductor device is concluded such that the active region of the device is placed at least partly within the layer with enhanced germanium concentration.

Abstract: An acoustic mirror includes constituent layers that are substantially odd multiples of ?/4. The constituent layers include a first impedance layer and a second impedance layer, where the first impedance layer includes a first material having a first acoustic impedance and a first dielectric constant, and the second impedance layer includes a second material having a second acoustic impedance and a second dielectric constant. The second acoustic impedance is higher than the first acoustic impedance, and the first dielectric constant is lower than the second dielectric constant.

Abstract: Overlapped electrodes of an electrical component are dimensioned in such a way that when there is translational displacement of one electrode in relation to the electrode situated opposite, their area of overlap remains within a manufacturing tolerance ?/2, and also remains constant within the tolerance limits when there is a simultaneous rotation of the electrodes with respect to one another. This is achieved in that the intersecting edge pairs of the overlapping electrodes are designed parallel to one another, whereby the length, measured in the direction parallel to the respective edge pair, of the corresponding electrode everywhere exceeds by ? the corresponding length of the area of overlap.

Abstract: A frequency-tunable resonator comprises a basic element having at least one piezoelectric layer and at least one semiconducting layer. The electrodes, formed on main surface situated opposite one another of the basic element, are loaded with an external voltage, whereby the resonant frequency of the basic element or of the resonator can be in dependence on the voltage.

Abstract: Proposed is a resonator which works with bulk acoustic waves and is based on a layer structure known in the art, which is arranged over a substrate. According to the invention, the total surface of the layer structure, including all resonators contained therein, is covered with a dielectric layer and a metal layer which together form an acoustic mirror, a low-k dielectric being used for the dielectric layer. The total-surface mirror offers broadband functionality over a suitable frequency range. The dielectric contained within the mirror acts as a sealing protective layer for the resonator or resonators.

Abstract: A memory cell is provided for storing a bit. The memory cell includes a capacitor with capacitor electrodes for storing electric charge and a semiconductor switch with a channel region, the electrical conductivity of which is controllable, for connecting the capacitor to a bit line, via which a bit can be written to and read from the memory cell. The channel region and a metallic terminal region connected to one of the capacitor electrodes form a metal-semiconductor junction.

Abstract: The invention relates to a front-end circuit, suitable for a plurality of mobile wireless systems, for separating different frequency bands. According to the invention, separation of the frequency bands occurs by means of band-pass filters connected in parallel signal paths and executed on the basis of thin-layer resonators, which, as a result of their high quality, allow for a high degree of selection between the frequency bands.

Abstract: A component working with acoustic bulk waves is provided that has a multi-layer substrate, where the multi-layer substrate comprises an integrated matching network and further circuit elements for adapting the electrical filter properties and can serve as carrier substrate for thin-film resonators.

Abstract: For a BAW resonator or a stacked-crystal filter, an acoustic mirror is proposed that has at least one layer pair of ?/4 or 3?/4 layers, where each layer pair has a first layer with lower acoustic impedance and a second layer with higher acoustic impedance relative to it and where a low-k dielectric is selected as the material with lower acoustic impedance.