Abstract:
In an accelerometer sensor of crystalline material, whose components are composed partly of monocrystalline and partly of polycrystalline material, a band-shaped seismic mass preferably is composed of polycrystalline material, whose suspension by means of suspension segments of monocrystalline material at the end regions permits a movement in the longitudinal direction upon the occurrence of an acceleration. Parallel plates extend from this mass at right angles to their longitudinal direction and, together with additional plates, which run parallel to said plates and are anchored at a base, form a capacitor arrangement and are composed, in particular, of monocrystalline material. At least the monocrystalline material is doped to attain an electric conductivity. When lightly doped, the long and thin plates and suspension segments have a high conductivity, given a very small mechanical prestressing, and can easily be isotropically undercut. The polycrystalline formation of the seismic mass can be designed to be very wide and large by etching away an underlying sacrificial oxide.
Abstract:
An acceleration sensor and a method of making an acceleration sensor is described in which a movable sensor element is located in a hollow space formed in the middle of three silicon plates. During production, air can be removed from the hollow space through a hole in one of the two outer plates. The hole is then closed by an additional plate, which allows for a defined pressure to be set in the hollow space.
Abstract:
A method of making acceleration sensors with integrated measurement of internal pressure includes connecting multiple plates to each other, thereby defining internal cavities. The tightness of these connections or bonds is checked and controlled during the manufacturing process. The plates define membrane portions adjacent each cavity, the membranes deforming in accordance with the internal pressure in the adjacent cavity. Preferably, the internal pressure of the sensor is measurable by detecting deformation of a sensor wall which defines a membrane.
Abstract:
A micromechanical sensor includes a support of silicon substrate having an epitaxial layer of silicon applied on the silicon substrate. A part of the epitaxial layer is laid bare to form at least one micromechanical deflection part by an etching process. The bared deflection part is made of polycrystalline silicon which has grown in polycrystalline form during the epitaxial process over a silicon-oxide layer which has been removed by etching. In the support region and/or at the connection to the silicon substrate, the exposed deflection part passes into single crystal silicon. By large layer thicknesses, a large working capacity of the sensor is possible. The sensor structure provides enhanced mechanical stability, processability, and possibilities of shaping, and it can be integrated, in particular, in a bipolar process or mixed process (bipolar-CMOS, bipolar-CMOS-DMOS).
Abstract:
A method for fabricating micromechanical components, which provides for depositing one or a plurality of sacrificial layers on a silicon substrate and, thereon, a silicon layer. In subsequent method steps, a structure is patterned out of the silicon layer, and the sacrificial layer is removed, at least under one section of the structure. The silicon layer is doped by an implantation process.
Abstract:
An acceleration sensor is composed of a three-layer system. The acceleration sensor and conductor tracks are patterned out of the third layer. The conductor tracks are electrically isolated from other regions of the third layer by recesses and electrically insulated from a first layer by a second electrically insulating layer. In this manner, a simple electrical contacting is achieved, which is configured out of a three-layer system. One exemplary application of the acceleration sensor includes mounting the acceleration sensor on a vibrational system of an rpm (rate-of-rotation sensor). This simplifies the manufacturing of an rpm sensor, since the vibrational system and the acceleration sensor are configured out of a three-layer system, wherein the conductor tracks are run into the frame of the rpm sensor in which the vibrational system is suspended, so as to allow excursion.
Abstract:
A micromechanical component includes a one-piece surface structure that is created on a substrate. The one-piece surface structure is attached to the surface of the substrate by at least two anchoring areas. The anchoring areas are a small distance apart, which is comparatively small in comparison with the lateral dimension of the surface structure. The surface structure has movable electrodes. Opposite them there are rigid electrodes that are attached to the substrate by additional anchoring areas. The additional anchoring areas also have a small distance between one another and to the anchoring areas.
Abstract:
A method for producing acceleration sensors is proposed, in which a silicon layer that is deposited in an epitaxial application system is used. Above sacrificial layers (2) applied to the substrate (1), the material grows in the form of a polysilicon layer (6), which has a certain surface roughness. By application of a photoresist and by a wet etching process, this surface roughness is eliminated. Alternatively, chemical-mechanical smoothing is contemplated.
Abstract:
A sensor includes a first silicon layer, and a sensor element including at least one electrode structured from the first silicon layer. The sensor also includes at least one connecting element also structured from the first silicon layer. The connecting element has a doping less than the doping of the electrode. The sensor comprises at least one conductor track on the first silicon layer routed over the connecting element and coupled to the sensor element for supplying an external signal.
Abstract:
A contacting of a capacitive accelerometer sensor of monocrystalline material is achieved by a capacitive accelerometer sensor having a structure etched out of a monocrystalline layer arranged on a substrate, including a seismic mass that is only joined to the substrate by suspension segments and executing a movement in its longitudinal direction in response to the occurrence of an acceleration of parallel, plate-like first fingers extending out from this mass at right angles to their longitudinal direction and of plate-like second fingers running parallel to the first fingers and anchored to the substrate. The first and second fingers form a capacitor arrangement. The suspension segments, which are anchored with their end region that is distant from the seismic mass to the substrate, and second fingers are electrically isolated, by an isolation strip, from the other remaining layer of monocrystalline material. A passivation layer extends over the isolation strip, and at least partially over the remaining layer. Conductors arranged on the passivation layer and serving as connecting leads for the capacitor arrangement extend across the isolation strip up to the connections of the capacitor arrangement, and are contacted there.