Abstract:
A wafer for use in a MEMS device having two doped layers surrounding an undoped layer of silicon is described. By providing two doped layers around an undoped core, the stress in the lattice structure of the silicon is reduced as compared to a solidly doped layer. Thus, problems associated with warping and bowing are reduced. The wafer may have a pattered oxide layer to pattern the deep reactive ion etch. A first deep reactive ion etch creates trenches in the layers. The walls of the trenches are doped with boron atoms. A second deep reactive ion etch removes the bottom walls of the trenches. The wafer is separated from the silicon substrate and bonded to at least one glass wafer.
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:
A semiconductor accelerometer is formed by attaching a semiconductor layer to a handle wafer by a thick oxide layer. Accelerometer geometry is patterned in the semiconductor layer, which is then used as a mask to etch out a cavity in the underlying thick oxide. The mask may include one or more apertures, so that a mass region will have corresponding apertures to the underlying oxide layer. The structure resulting from an oxide etch has the intended accelerometer geometry of a large volume mass region supported in cantilever fashion by a plurality of piezo-resistive arm regions to a surrounding, supporting portion of the semiconductor layer. Directly beneath this accelerometer geometry is a flex-accommodating cavity realized by the removal of the underlying oxide layer. The semiconductor layer remains attached to the handle wafer by means of the thick oxide layer that surrounds the accelerometer geometry, and which was adequately masked by the surrounding portion of the top semiconductor layer during the oxide etch step. In a second embodiment support arm regions are dimensioned separately from the mass region, using a plurality of buried oxide regions as semiconductor etch stops.
Abstract:
The invention proposes a particularly simple, cost-effective method for producing a micromechanical membrane structure with access from the rear of the substrate. Said method is based on a p-doped Si substrate (1) and comprises the following process steps: n-doping of at least one continuous lattice-type region (2) of the substrate surface; porous etching of a substrate region (5) below the n-doped lattice structure (2); creation of a cavity (7) in said substrate region (5) below the n-doped lattice structure (2); growing of a first monocrystalline silicon epitaxial layer (8) on the n-doped lattice structure (2). The invention is characterised in that at least one opening (6) in the n-doped lattice structure (2) is dimensioned in such a way that it is not closed by the growing first epitaxial layer (8) and instead forms an access opening (9) to the cavity (7); an oxide layer (10) is created on the cavity wall; A rear face access (13) to the cavity (7) is created, the oxide layer (10) acting as an etch stop layer; and the oxide layer (10) is removed in the region of the cavity (7) producing a rear face access (13) to the membrane structure (14) lying above the cavity (7).
Abstract:
The present invention proposes a method for producing a micromechanical membrane structure (11) having a fixed counter element (12), which starts from a p-doped silicon substrate (1). Said method comprises the following processing steps: n-doping of at least one coherent latticed area (2) of the substrate surface; (Figure 1a) porous etching of a substrate area (3) below the n-doped lattice structure (2); (Figures 1b-c) oxidation of the porous silicon; (Figure 1d) generating at least one sacrificial layer (5) above the n-doped lattice structure (2); (Figure 1e) depositing and structuring at least one thick epitaxial layer (7); (Figures 1f-g) removing the sacrificial layer (5) between the thick epitaxial layer (7) and the n-doped lattice structure (2) and generating a cavity (10) in the silicon substrate (1) below the n-doped lattice structure (2) by removing the oxidized porous silicon (oxPorSi); (Figure 1h) so that the exposed n-doped lattice structure (2) forms a membrane structure (11) and at least one fixed counter element (12) is implemented in the structured thick epitaxial layer (7).
Abstract:
Mit der vorliegenden Erfindung wird ein besonders einfaches und kostengünstiges Verfahren zur Herstellung einer mikromechanischen Membranstruktur mit Zugang von der Substratrückseite vorgeschlagen. Dieses Verfahren geht von einem p-dotierten Si-Substrat (1) ausgeht und umfasst die folgenden Prozessschritte: n-Dotierung mindestens eines zusammenhängenden gitterförmigen Bereichs (2) der Substratoberfläche, porös Ätzen eines Substratbereichs (5) unterhalb der n-dotierten Gitterstruktur (2), Erzeugen einer Kaverne (7) in diesem Substratbereich (5) unterhalb der n-dotierten Gitterstruktur (2); Aufwachsen einer ersten monokristallinen Silizium-Epitaxieschicht (8) auf der n-dotierten Gitterstruktur (2). Es ist dadurch gekennzeichnet, dass mindestens eine Öffnung (6) der n-dotierten Gitterstruktur (2) so dimensioniert wird, dass sie durch die aufwachsende erste Epitaxieschicht (8) nicht verschlossen wird sondern eine Zugangsöffnung (9) zu der Kaverne (7) bildet; dass auf der Kavernenwandung eine Oxidschicht (10) erzeugt wird; dass ein Rückseitenzugang (13) zur Kaverne (7) erzeugt wird, wobei die Oxidschicht (10) auf der Kavernenwandung als Ätzstoppschicht dient; und dass die Oxidschicht (10) im Bereich der Kaverne (7) entfernt wird, so dass ein Rückseitenzugang (13) zu der über der Kaverne (7) ausgebildeten Membranstruktur (14) entsteht.
Abstract:
The invention relates to a method for producing micromechanical structures having a raised lateral wall progression or an adjustable angle of inclination. The micromechanical structures are etched out of an SiGe-mixed semiconductor layer (3a, 3b, 30, 30a, 30b, 50) provided on, or deposited on, a silicon semiconductor layer (1, 10), by dry-chemical etching of the SiGe-mixed semiconductor layer (3a, 3b, 30, 30a, 30b, 50). The lateral wall progression of the micromechanical structure is formed by varying the germanium part in the SiGe-mixed semiconductor layer (3a, 3b, 30, 30a, 30b, 50) to be etched. There is a higher germanium part in regions that are to etched more aggressively. The variation of the germanium part in the SiGe-mixed semiconductor layer (3a, 3b, 30, 30a, 30b, 50) is adjusted by a method selected from a group wherein an SiGe-mixed semiconductor layer (3a, 3b, 30, 30a, 30b, 50) having a varying germanium content is deposited, wherein germanium is introduced into a silicon semiconductor layer or an SiGe-mixed semiconductor layer (3a, 3b, 30, 30a, 30b, 50), wherein silicon is introduced into a germanium layer or an SiGe-mixed semiconductor layer (3a, 3b, 30, 30a, 30b, 50), and/or wherein a SiGe-mixed semiconductor layer (3a, 3b, 30, 30a, 30b, 50) is subjected to thermal oxidation.
Abstract:
L'invention porte notamment sur un procédé de réalisation de motifs ultérieurs dans une couche sous-jacente (120), le procédé comprenant au moins une étape de réalisation de motifs antérieurs dans une couche imprimable (110) surmontant la couche sous-jacente (120), la réalisation des motifs antérieurs comprenant une impression nanométrique de la couche imprimable (110) et laissent en place une couche continue formée par la couche imprimable (110) et recouvrant la couche sous-jacente (120), caractérisé en ce qu'il comprend l'étape suivante: au moins une étape de modification de la couche sous-jacente (120) par implantation (421) d'ions au sein de la couche sous-jacente (120), l'implantation (421) étant réalisée au travers de la couche imprimable (110) comprenant les motifs ultérieurs, les paramètres de l'implantation (421) étant choisis de manière à former dans la couche sous-jacente (120) des zones (122) implantées et des zones non implantées, les zones non implantées définissant les motifs ultérieurs et présentant une géométrie qui est fonction des motifs antérieurs.