Abstract:
An inertia force sensor comprising a mass body (11) displaced when a force is applied to the mass body (11), at least one holding beam (12) holding the mass body (11), and a fixing section (13) fixing one end of the holding beam (12) so as to sensing the inertia force acting on the mass body (11) based on the displacement of the mass body (11), characterized in that the mass body (11) has a hollow structure made by removing the inside of a silicon substrate (1) by one process of etching, and the fixing section (13) is at least a part of the main body of the silicon substrate (1). Since the inertia force sensor is made of single crystal silicon, the mechanical characteristics and reliability are greatly imporoved.
Abstract:
This invention provides a miniaturized silicon thermal flow sensor with improved characteristics, based on the use of two series of integrated thermocouples (6, 7) on each side of a heater (4), all integrated on a porous silicon membrane (2) on top of a cavity (3). Porous silicon (2) with the cavity (3) underneath provides very good thermal isolation for the sensor elements, so as the power needed to maintain the heater (4) at a given temperature is very low. The formation process of the porous silicon membrane (2) with the cavity (3) underneath is a two-step single electrochemical process. It is based on the fact that when the anodic current is relatively low, we are in a regime of porous silicon formation, while if this current exceeds a certain value we turn into a regime of electropolishing. The process starts at low current to form porous silicon (2) and it is then turned into electropolishing conditions to form the cavity (3) underneath.Various types of thermal sensor devices, such as flow sensors, gas sensors, IR detectors, humidity sensors and thermoelectric power generators are described using the proposed methodology. Furthermore the present invention provides a method for the formation of microfluidic channels (16) using the same technique of porous silicon (17) and cavity (16) formation.
Abstract:
A method for protecting a material of a microstructure comprising said material and a noble metal layer (8) against undesired galvanic etching during manufacture comprises forming on the structure a sacrificial metal layer (12) having a lower redox potential than said material, the sacrificial metal layer (12) being electrically connected to said noble metal layer (8).
Abstract:
The invention relates to the production of a micromechanical component, comprising a substrate (10), made from a substrate material with a first doping type (p), a micromechanical functional structure arranged in the substrate (10) and a cover layer for the at least partial covering of the micromechanical functional structure. The micromechanical functional structure comprises regions (15; 15a; 15b; 15c; 730; 740; 830) made from the substrate material with a second doping type (n), at least partially surrounded by a cavity (50; 50a-f) and the cover layer comprises a porous layer (30) made from the substrate material.
Abstract:
The process comprises forming a buried sacrificial layer (5) of porous silicon in the starting substrate (2) and then a single-crystal epitaxial layer (7) intended to accommodate both the sensitive element and the integrated circuit. After forming electronic components (12, 18) in the epitaxial layer, the epitaxial layer (7) is anisotropically etched over the buried sacrificial layer (5) to form trenches (27) through which the buried sacrificial layer is then etched and removed. The suspended mass (30) thus obtained has high mechanical properties, high thickness, the process is wholly compatible with standard microelectronics techniques and can be implemented at low cost.
Abstract:
An ultra-high charge density electret is disclosed. The ultra-high charge density electret includes a three-dimensional structure having a plurality of sidewalls. A porous silicon dioxide film is formed on the plurality of sidewalls, and the porous silicon dioxide film is charged with a plurality of positive or negative ions.