MEMS with adjusted semiconductor behavior

Abstract

A MEMS comprising a movable element and a drive device comprising a first doped semiconductor electrode and a second doped semiconductor electrode of the movable element, the second doped semiconductor electrode is arranged opposite the first semiconductor electrode and is configured to generate an electrostatic force between the first semiconductor electrode and the second semiconductor electrode while generating a first carrier change region in the first semiconductor electrode and a second carrier change region in the second semiconductor electrode.

Description

TECHNICAL FIELD

[0001] The present invention relates to MEMS with adjusted semiconductor behavior, in particular to the implementation of accumulation regions and space charge regions for controlling a movable element. The invention further relates to a substrate with a controlled doping. BACKGROUND

[0002] In MEMS with a movable element, such as a movable element that can be used for moving a fluid for example, electro-actuation can be implemented using semiconductor materials, in particular doped semiconductor materials. An example in this regard is an electrode arrangement for electrostatic or electrodynamic excitation using electrostatic or electrodynamic forces. Such electrode arrangements can be provided at least partially using doped semiconductor materials.

[0003] Furthermore, but not limited thereto, a reproducible and symmetrical deflection of a movable element in a MEMS is advantageous for some implementations. MEMS loudspeakers and MEMS microphones complementary thereto can be considered as non-limiting examples in this regard, wherein a movable element for interacting with a fluid, such as air, is advantageously deflected uniformly in one direction and its opposite direction to enable the generation of low-disturbance sound waves in the fluid.

[0004] For some embodiments, it is also possible to deliberately deviate from such symmetrical operation, wherein this is still within the framework of the requirement that the movement of the movable element has a good controllability. SUMMARY

[0005] Therefore, it is desirable to have a MEMS with a movable element whose movement can be actuated with little disturbance.

[0006] It is an object of the present invention to provide a MEMS with a movable element that allows for a low-disturbance actuation of the movable element.

[0007] This object is achieved by the subject matter of the independent claims.

[0008] The core idea of the present invention is that it has been recognized that disturbances in the movement of a MEMS are due to varying regions of different kinds in the semiconductor material for movement in different directions, and that these disturbances can advantageously be avoided if the MEMS is configured such that varying regions of the same kind are arranged opposite to each other and optionally adjacent to each other.

[0009] According to one embodiment, a MEMS comprises a movable element and a driving device comprising a first doped semiconductor electrode of the movable element and a second doped semiconductor electrode arranged opposite the first semiconductor electrode, the second doped semiconductor electrode being configured to generate an electrostatic force between the first semiconductor electrode and the second semiconductor electrode while generating a first carrier variation zone in the first semiconductor electrode and a second carrier variation zone in the second semiconductor electrode for deflecting the movable element. Adjustment of the variation zones allows adjustment of the deflection behavior.

[0010] In some implementations, the driving device is implemented using a first doped semiconductor electrode and a second doped semiconductor electrode and a third doped semiconductor electrode. The first doped semiconductor electrode is part of or arranged on the movable element and the second doped semiconductor electrode and the third doped semiconductor electrode are arranged opposite the first semiconductor electrode. The doped semiconductor electrodes are configured to alternately generate an electrostatic force between the first semiconductor electrode and the second semiconductor electrode and between the first semiconductor electrode and the third semiconductor electrode while generating a first carrier variation zone in the first semiconductor electrode, a second carrier variation zone in the second semiconductor electrode and a third carrier variation zone in the third semiconductor electrode for deflecting the movable element. The second carrier variation zone and the third carrier variation zone are formed of the same kind. The fact that the second carrier variation zone and the third carrier variation zone are of the same kind allows an equal influence on the generated force and on the movement by the variation zones.

[0011] According to one embodiment, a MEMS comprises a movable element and a driving device. The driving device comprises a first electrode of the movable element and a second electrode formed as a doped semiconductor electrode, the second electrode being arranged opposite the first electrode and being configured to generate an electrostatic force between the first electrode and the second electrode while generating a first carrier variation zone in the second electrode and for deflecting the movable element, which also allows advantageously setting the deflection behavior.

[0012] In some implementations, the drive arrangement comprises a first electrode of the movable element, which can be part of the movable element or can be arranged in the movable element. Furthermore, the drive arrangement comprises a second electrode formed as a doped semiconductor electrode and a third electrode formed as a doped semi-conductor electrode. The second electrode and the third electrode are arranged opposite to the first electrode and are configured to generate electrostatic forces alternately between the first electrode and the second electrode and between the first electrode and the third electrode, while a first carrier change region is generated in the second electrode and a second carrier change region is generated in the third electrode for deflecting the movable element. The first carrier change region and the second carrier change region are formed differently from each other; in this embodiment, the different change regions of the second electrode and the third electrode are used for uniform movement.

[0013] Other advantageous implementations are the subject of dependent claims. BRIEF DESCRIPTION OF DRAWINGS

[0014] A particularly preferred embodiment of the application will be explained below with reference to the accompanying drawings, in which:

[0015] Figures la to lc show schematic side cross-sectional views of different possible implementations of a MEMS according to embodiments;

[0016] Figure 2 A schematic side cross-sectional view of a MEMS with cover drive on both sides according to an embodiment is shown;

[0017] Figure 3 A schematic side cross-sectional view of a known MEMS component is shown;

[0018] Figure 4 A schematic side cross-sectional view of a part of a MEMS according to an embodiment which overcomes the disadvantages of the MEMS of Figure 3

[0019] Figures 5a to 5b show a schematic view of, for example, an n-doped semiconductor material, for example comprising phosphorous dopants;

[0020] Figures 6a to 6b show a schematic view of, for example, a p-doped semiconductor material, for example comprising boron dopants;

[0021] Figures 7a to 7d show schematic side cross-sectional views of a MEMS according to an embodiment in which the electrodes are doped differently;

[0022] Figures 8a to 8b show schematic side cross-sectional views of a MEMS according to an embodiment in which the opposite electrodes are doped to the same kind;

[0023] ​Figures 9a to 9b show respective configurations of the semiconductor electrode and the movable element according to Figures 8a to 8b with a varying actuation voltage according to embodiments;

[0024] Figure 10 a schematic top view of a MEMS formed as a comb drive according to embodiments is shown; and

[0025] Figures 11a to 11b show schematic side cross-sectional views of a MEMS according to embodiments in which the electrodes for driving the movable element form different variation zones. DETAILED DESCRIPTION

[0026] Before embodiments of the present application are explained in detail below, it is to be understood that the same elements, objects and / or structures or ones having the same function or effect can be designated with the same reference numerals throughout the drawings and that the description of these elements, objects and / or structures can be interchanged with one another.

[0027] Embodiments described below will be described with reference to a plurality of details. However, the embodiments can also be implemented without these details. In addition, for the purpose of ease and understanding, block diagrams will be used as an alternative to detailed descriptions in order to describe the embodiments. Furthermore, the details and / or features of the individual embodiments can be combined easily, unless explicitly described to the contrary.

[0028] The embodiments described below relate to MEMS having movable elements and driving means, wherein electrodes formed on, in or with the movable elements can be doped semiconductor electrodes or can also be formed differently in alternative implementations, for example using metallic materials. According to embodiments, electrodes for interacting with this electrode are or comprise doped semiconductor electrodes, wherein these semiconductor electrodes can react with the movement of charge carriers when an electric potential is applied and when electrostatic or electrodynamic forces are generated. The embodiments are based on the knowledge of this effect and on measures taken in order to make these effects usable, in particular for MEMS loudspeakers, in such a way that the movement of the movable elements in different directions can occur identically or symmetrically, which is advantageous in MEMS loudspeakers for the quality of the loudspeaker signal obtained.

[0029] Embodiments of the present application are described based on a multi-layer MEMS structure, but the present application is not limited thereto.

[0030] Embodiments relate to the enrichment or accumulation and depletion of charge carriers in semiconductor materials. In the context of the embodiments described herein, the term "space charge region" is used synonymously with "depletion region". In contrast, an accumulation region or accumulation zone can exhibit an enrichment of movable charge carriers.

[0031] WO 2022 / 117197 A1 describes a MEMS component with an actuator arranged symmetrically above an electrode gap. This allows for symmetric actuation and approximately linear movement of the actuator.

[0032] WO 2021 / 093950 describes a laterally deflectable MEMS element consisting of three partial elements to allow for high and adjustable linearity.

[0033] EP 3 867 191 A1 discloses how a device of a MEMS can be made to look as if the deflection has been linearized by mechanical design. This is achieved by choosing a symmetric electrode arrangement, the symmetry of which is exactly related to the influence of non-linearity. This is thus fully or partially counteracted in at least one specific operating range. The disadvantage of these known concepts is that the space charge region and the accumulation region in the system are not positively influenced, controlled or considered.

[0034] Fig. la shows a schematic side sectional view of a possible implementation of a MEMS 101 according to an embodiment. The MEMS 101 comprises a movable element 12 which can be arranged in a cavity of the MEMS 101. The cavity can be delimited, for example, by a bottom substrate or wafer 14 on a first side and a cover substrate or wafer 16 on the opposite side. The movable element 12 can be arranged between the bottom wafer 14 and the cover wafer 16 and can be deflectable along a stacking direction z and / or perpendicular thereto, e.g. along an x-direction. The MEMS 101 comprises a driving device 18 for deflecting the movable element 12. To this end, an electrode 22 is provided which is fixedly connected to the movable element 12, which forms part of the movable element 12 and / or which can be arranged on the movable element 12. Thus, for example, the electrode 22 can comprise a metallic material deposited on the movable element 12, e.g. comprising a semiconductor material, a polymer, a ceramic, etc. Alternatively or additionally, the movable element 12 can also comprise or be formed of a metallic material, such that the electrode 22 is formed by a structure of the movable element 12. By forming the movable element 12 to comprise a doped semiconductor material, a similar approach can be achieved which allows for applying an electric potential to the movable element 12 to use the movable element 12 as an electrode. This doping of the semiconductor material of the movable element 12 can also be done only in regions, such that the electrode 22 can be provided only in regions in the movable element 12. The electrically conductive structure, e.g. the doped semiconductor material and / or the metallic material, can be arranged on a surface of the movable element 12 or can be embedded or buried in the structure of the movable element 12.

[0035] The drive arrangement 18 further comprises doped semiconductor electrodes 241 and 242 which are configured to be supplied with an electric potential. The movable element and / or the movable electrode 22 can be arranged opposite to the electrodes 241 and 242 which are not necessarily stationary. Thus, for example, a first potential difference between the electrode 22 and the electrode 241 can be used for a deflection in positive or negative x-direction, while another potential difference between the electrode 22 and 242 can be used for a deflection in the opposite direction. It should be noted that in the context of the embodiments described herein, also only one of the electrodes 241 or 242 can be arranged. Such a drive arrangement comprises a first doped semiconductor electrode 22 and a second doped semiconductor electrode 241 or 242 of the movable element 12, for example as an asymmetric comb drive. In this implementation, the second doped semiconductor electrode is arranged opposite to the first semiconductor electrode 22 and configured to generate an electrostatic force between the first semiconductor electrode and the second semiconductor electrode 241, while generating a first carrier change region in the first semiconductor electrode 22 and a second carrier change region in the second semiconductor electrode 241 for deflecting the movable element 12. In an advantageous implementation, this setup is extended by a third electrode. Then, a third doped semiconductor electrode 242 is arranged opposite to the first semiconductor electrode 22 together with the second doped semiconductor electrode, wherein the semiconductor electrodes are configured to generate an electrostatic force between the first semiconductor electrode and the second semiconductor electrode and between the first semiconductor electrode and the third semiconductor electrode, alternately, while generating a first carrier change region in the first semiconductor electrode and a second carrier change region in the second semiconductor electrode and a third carrier change region in the third semiconductor electrode for deflecting the movable element. The second carrier change region and the third carrier change region are of the same kind.

[0036] Fig. lb shows a schematic side sectional view of the MEMS 102 in relation to another configuration of the embodiments. Here, again, the movable element 12 is arranged between the semiconductor electrodes 241 and 242 and the drive arrangement 18 is configured to provide an electrostatic force between the electrodes 22 and 241 or 22 and 242 for deflecting the movable element 12 in positive or negative x-direction.

[0037] Fig. 1 c shows a schematic side sectional view of a MEMS 103 in connection with the embodiments discussed herein, wherein the movable element 12 is arranged between semiconductor electrodes 241 and 242, wherein the semiconductor electrode 241 is arranged on or in the bottom wafer 14, wherein in particular an out-of-plane force can be generated to deflect the movable element 12 out of the x / y-plane. To this end, for example, the first electrode 221 and the second electrode 222 can be part of the movable element 12, however, this is not mandatory. Thus, for example, it is conceivable that the movable element 12 is realized by a doped semiconductor material or a metallic material, wherein the movable element 12 itself can provide the common electrode 22 for the semiconductor electrodes 241 and 242.

[0038] As can be seen from Figs. 1 a to 1 c, the movement of the movable element 12 can occur in-plane as shown in Figs. 1 a and 1 b or out-of-plane as shown in Fig. 1 c. In this case, the arrangement of the semiconductor electrodes 241 and 242 is neither limited to two nor to a specific spatial position, nor are the electrodes of the movable element necessarily doped semiconductor electrodes.

[0039] The embodiments allow for an advantageous use of semiconductor electrodes 241 and 242 while at the same time obtaining a high-quality acoustic signal in the case of actuation of the MEMS as a loudspeaker. The same effect can be achieved when the MEMS is used as a sensor, for example as a microphone or the like.

[0040] In this case, the explanations relating to Figs. 1 a to 1 c merely provide exemplary structures of the described embodiments without limiting the arrangement of the cover wafer and / or the bottom wafer or the like.

[0041] The embodiments are described herein as MEMS components having a layer stack which consists at least of a substrate layer and in which electrodes and passive elements are arranged. Further layers relate to the bottom, which can also be referred to as process wafer, and the cover, which is also referred to as cover wafer. Both the cover wafer and the process wafer can be connected to the substrate plane, i.e. the plane of the movable element, by means of material bonding, preferably bonding, whereby an acoustically sealed gap can be formed in the component. This gap can correspond to the device plane or device wafer, in which the deformable component is deformed, in other words, the deformation occurs in-plane.

[0042] WO 2022 / 117197 A1 describes a MEMS with so-called cover driving. WO The content of 2022 / 117197 A1 is hereby fully incorporated into the present specification. The basic unit of a lid drive (see e.g. Fig. 1a or Fig. 1c) can be roughly divided into three elements. A wing or movable element 12 and two electrodes. These three elements are electrically and spatially separated from each other and can assume or can be supplied with different electric potentials. For example, the semiconductor electrodes 241 and 242 can be placed above the wing, e.g. as a lid wafer variant, and / or below the wing (as a bottom wafer variant). Combinations thereof are possible.

[0043] When a voltage is applied between the movable element / wing and the electrode 241, the wing can move towards the electrode 241. When a voltage is applied between the wing and the electrode 242, the wing can move towards the electrode 242, wherein the reversed potential can also cause a reversal of the direction.

[0044] The electrodes 241 and 242 are considered in relation to the embodiments discussed herein for the lid wafer case and are sometimes referred to as lid electrode 1 and lid electrode 2, but the embodiments are not limited thereto. It is noted that terms such as top, bottom, left, right, front, back, etc. can be interchanged as needed depending on the changed orientation of the object in space and are only used for better understanding of the embodiments.

[0045] This means that the relationships described herein for the lid wafer case can easily be seen as an alternative or also used for the bottom wafer case in addition. For this purpose, the electrodes can be placed e.g. below the wing. In this case, the electrodes can be seen as and referred to as electrodes

[0046] Examples of such structures are shown in Figure 2 Fig. 1a and Fig. 1c. In Fig. 1a, a schematic side sectional view of a MEMS 20 is shown. Here, the movable element 12 is arranged between the lid electrodes 24 1.1 and 24 1.2 and between the bottom electrodes 24 2.1 and 24 2.2 In a preferred implementation, the actuation means 26 of the MEMS 20 are configured to provide one or more actuation signals 28 to provide or trigger electric potentials to the movable element 12 or to the electrodes 22 and 24 1.1 to 24 2.2 The actuation means 26 can also easily be external elements which can be coupled to the electrodes by means of an interface.

[0047] For particularly high-quality sound signals that can be generated by means of the MEMS 20 and / or for particularly low-interference sensor signals, it can be preferred to apply the same electric potential to the electrodes 24 1.1 and 24 2.1 on the one hand and to the electrodes 24 1.2 and 24 2.2The same potentials are applied. However, in this case the semiconductor electrodes 24 1.1 to 24 2.2 An effect occurs which produces an undesired disturbance in the sound signal and / or the electrical signal in the known structure. It is also pointed out at the outset that the generation of the electrostatic forces for the deflection, in particular the alternating actuation, is not to be understood as meaning that the respective other electrode is connected without a potential. Rather, it is also possible to apply different voltages between the movable element on the one hand and the electrode 1 on the other hand and between the movable element on the one hand and the electrode 2 on the other hand at the same time in order to obtain a greater degree of control of the wing movement, which can also be referred to as a balanced mode.

[0048] The cap drive described herein can be used in applications which particularly benefit from a linear relationship between the actuation signal and the component reaction, such as, for example, micro loudspeakers, pm loudspeakers which are operated or actuated in a so-called balanced mode.

[0049] Figure 3 A schematic side sectional view of a known MEMS component is shown, in which the semiconductor electrodes 24'1 and 24'2 comprise an n-doped semiconductor material and are arranged on a p-doped cap wafer 16'. Potentials 321 (also referred to as DC+) and 322 (also referred to as DC-) can be applied to the semiconductor electrodes 24'1 and 24'2.

[0050] On the one hand, a dielectric 34, for example air or an oxide material, is arranged between the semiconductor electrodes 24'1 and 24'2 and the movable element 12', wherein, alternatively, a vacuum can also be used for the electrical insulation. The movable element 12' is formed from a boron-doped p-semiconductor material, so that, on the basis of an alternating AC signal 36 applied to the movable element 12', electric fields 381 and 382 are formed. Due to the different field propagation directions of the fields 381 and 382, for example due to different voltage differences, a space charge region 42 opposite the semiconductor electrode 24'1 and a build-up region 44 opposite the semiconductor electrode 24'2 are formed in the movable element 12'. While the charge carriers 46 can be underrepresented in the space charge region 42 due to the migration, they can be overrepresented in the build-up region 44 due to the migration. The charge carriers 46 can be holes in a p-doped semiconductor material. For an n-doped semiconductor, the charge carriers can correspondingly be electrons.

[0051] The existence or formation of both regions, the space charge region 42 and the build-up region 44, which can occur simultaneously, can produce a symmetrical signal or a signal with the same absolute amplitude DC+ and DC- (different strong interaction or force is generated), so that on this basis a deviation of the obtained movement of the movable element can occur, since the space charge region 48 in the semiconductor electrode 24'1 and the build-up region 52 in the semiconductor electrode 24'2 can provide corresponding forces.

[0052] In the context of the embodiments described herein, it can be assumed that in the case of n-doped semiconductor material, electrons e - form majority carriers, and holes h + form minority carriers. In n-doped semiconductor material, such as semiconductor electrode 24'2, e - accumulation can lead to particularly high conductivity and accumulation of holes h + form majority carriers, and electrons e - form minority carriers.

[0053] In contrast, the space charge regions 42 and 48 form respective regions of the movable element 12' or the semiconductor electrode 24'1 which are less conductive or not conductive.

[0054] The inventors consider the shown case to be disadvantageous in that the wing exhibits both a space charge region and an accumulation region at the same time. Furthermore, the respective semiconductor electrode, for example polysilicon, has either an accumulation region 52 or a space charge region 48.

[0055] In an exemplary operating mode, an AC signal 36 is provided in the voltage range of ± 12 V, and the DC voltages 321 and 322 can have potential values of, for example, +19 V and -19 V.

[0056] In other words, Figure 3 A basic cell of a known cover-driven is shown in a cross-sectional view.

[0057] Figure 4 A schematic side sectional view of a portion of a MEMS 40 according to an embodiment is shown, which overcomes the disadvantages of the MEMS 30. The movable element 12 can be formed according to the movable element 12' and comprises, for example, the same type of boron-doped semiconductor material. Likewise, the semiconductor electrodes 241 and 242 can be formed according to the semiconductor electrodes 24'1 and 24'2 of the MEMS 30 and comprise, for example, n-doped semiconductor material. The cover wafer 16 can optionally, but not necessarily, be p-doped.

[0058] Unlike the MEMS 30, for example, a positive DC voltage 321 will be applied to the movable element 12. An AC potential (AC+ / AC- 361 or 362) can be applied to the semiconductor electrode 241 or 242. Here, the potentials 361 and 362 can be understood as at least substantially inverse AC signals, and the absolute values with respect to voltage and / or frequency can be identical, for example, the same signal with a 180° phase offset. Deviations with respect to amplitude are possible, for example, in order to compensate for structural deviations affecting the movement of the movable element due to mutually different material stiffnesses.

[0059] The potential 321 at the movable element 12 can cause the formation of an accumulation region 44 in the movable element 12. At the same time, the application of the AC signals 361 and 362 can cause the formation of accumulation regions 521 and 522 in the semiconductor electrodes 241 and 242, such that the varying regions of the semiconductor electrodes 241 and 242 formed by the accumulation regions 521, 522 are of the same kind.

[0060] This allows a uniform implementation of the electric fields 381 and 382. This effect is also obtained if the accumulation regions 521 and 522 are both space charge regions, independently of whether the accumulation region 44 is maintained as an accumulation region or a space charge region, since the influence on the respective fields 381 and 382 is the same, i.e. both fields will be affected equally.

[0061] In an exemplary implementation, a voltage of approximately +19 V is applied to the movable element 12, and the voltage amplitude of the AC signals 361 and 362 is varied between +12 V and -12 V, wherein the signals 361 and 362 can be inverted relative to each other.

[0062] In the context of the embodiments described herein, advantages of the MEMS operation are obtained by arranging and providing varying regions. Space charge regions or accumulation regions are understood as varying regions. According to embodiments relating to the MEMS 40, for example, the varying regions of the semiconductor electrodes 241 and 242 are accumulation regions, or both are space charge regions.

[0063] According to embodiments, the varying regions of the semiconductor electrodes 241 and 242 and the movable element 12 along the longitudinal extension direction y of the movable element are identical or constant, i.e. a variation of the Figure 3 varying of the movable element 12' shown along the lateral direction x. It is particularly preferred that the variation between the varying regions along the lateral extension direction x in the movable element 12, i.e. the electrodes 22, is omitted. This can optionally be further improved if the semiconductor electrodes 241 and 242 also do not have or form different varying regions adjacent to each other during operation.

[0064] As Figure 4 shown, some embodiments provide that the varying regions of the movable element 12 and the semiconductor electrodes 241 and 242 are of the same kind. This can also apply unchanged if a corresponding drive is provided in the bottom wafer 14. However, it is alternatively also possible to use a complementary doping type there, which leads to a complementary behavior of the varying regions, for example space charge regions adjacent to the bottom wafer.

[0065] The MEMS 40 can have an actuation device 54 configured to actuate the drive device. The actuation device 54 can be configured to apply a constant voltage or DC potential to the semiconductor electrodes of the movable element 12 and to apply an alternating voltage AC to the semiconductor electrodes 241 and 242, wherein the alternating voltages 241 and 242 are particularly preferably opposite to each other. The preferred embodiment provides an actuation device, wherein the maximum absolute amplitude of the alternating voltage 361 and / or 362 is smaller than the absolute amplitude of the constant voltage, wherein the values of 12 V and 19 V are to be understood merely as examples. The increased absolute amplitude of the DC voltage relative to the AC voltage reliably allows different variation zones in the movable element 12' to be obtained, as Figure 3

[0066] According to an embodiment, a MEMS is provided, wherein at least two elements of the group of the first semiconductor electrode 241, the second semiconductor electrode 242 and the third semiconductor electrode have different doping types. In the MEMS 40, the semiconductor electrodes 241 and 242 are n-doped, while the movable element 12 or at least its electrodes are p-doped. In this specific implementation, the semiconductor electrode of the movable element 12 has a different doping type with respect to the second semiconductor electrode and the third semiconductor electrode, wherein it can also correspond to one of the two semiconductor electrodes 241 and 242.

[0067] Fig. 5a shows a schematic diagram of an n-doped semiconductor material, for example including phosphorus dopants (P) 58, wherein there are electrons 62 and holes 64. When different voltages U2 and U3 (for example -10 V and +10 V) are applied in the different regions, the distribution at the spatially identical voltage U1 (for example 0 V) can change. This can lead to the formation of accumulation zones 52 and space charge zones 48, for example based on carrier migration 66.

[0068] Figs. 6a and 6b show a corresponding scenario for p-doping of a semiconductor material using boron dopants 68. In comparison to the n-doping of Fig. 5b, the carrier migration 66 can occur in a different direction. The arrow direction of the arrows of the carrier migration 66 can indicate the direction of the electric field. If the applied potentials are interchanged, the arrow direction is thus also interchanged.

[0069] Fig. 7a shows a schematic block diagram of a movable element 12 and semiconductor electrodes 241 and 242 of a MEMS according to an embodiment. The configuration corresponds to the MEMS 40, wherein the semiconductor electrodes 241 and 242 are n-doped and at least the electrodes of the movable element 12 are p-doped.

[0070] Here, a positive DC voltage is preferably applied to the movable element 12.

[0071] ​Fig. 7b shows a configuration of the semiconductor electrodes 241 and 242 and the movable element 12 according to an embodiment, which is the opposite to Fig. 7a. The semiconductor electrodes 241 and 242 are for example p-doped and the movable element 12 is n-doped. Even though the electric fields 381 and 382 can be reversed this way, the generation of the accumulation regions 44, 521 and 522 can be obtained by changing the above-mentioned potentials in a corresponding way. This change can be related to the positive DC voltage (DC+) applied to the movable element 12 in Fig. 7a and the negative DC voltage (DC-) applied to the movable element 12 in Fig. 7b for example to obtain accumulation. Based on the n-type doping, it is preferable to apply a negative DC voltage to the movable element 12 to generate the accumulation regions.

[0072] Fig. 8a shows a schematic side cross-sectional view of a part of a MEMS according to an embodiment, wherein the first semiconductor electrode, the second semiconductor electrode 241 and the third semiconductor electrode 243 of the movable element 12 have the same doping type, here exemplarily n-type. While maintaining the potentials from Figure 4 This can result in the formation of a space charge region 42 instead of an accumulation region 44 at the movable element 12, but this does not contradict the uniformity of the electric fields 381 and 382 along the x-direction, thereby maintaining the advantage of actuating movement along the x-direction. To obtain a space charge region, it is preferable to apply a positive DC+ voltage to the n-type movable element.

[0073] Fig. 8b shows a schematic side cross-sectional view of a configuration according to an embodiment, which is complementary to the configuration of Fig. 8a, wherein the movable element 12 and the semiconductor electrodes 241 and 242 are p-doped. In comparison to Fig. 8a, the electric fields 381 and 362 can be reversed, but this can still allow for a uniform movement actuation of the movable element 12 along the x-direction. To obtain a space charge region, it is preferable to apply a negative DC voltage (DC-) to the p-type movable element.

[0074] In the configurations of Fig. 8a and Fig. 8b, the varying regions of the movable element on the one hand and the semiconductor electrodes 241 and 242 on the other hand can be of different kind. However, varying regions of the same kind can be arranged in the respective MEMS plane, for example, on the one hand the MEMS plane of the semiconductor electrodes 241 and 242 and on the other hand the MEMS plane of the movable element 12. With reference to Fig. 7a and Fig. 8a, the actuation means 54 can be configured to apply a negative (DC) voltage to the n-doped semiconductor electrodes 241 and 242 (relative to the element 12). With reference to Fig. 7b and Fig. 8b, the actuation means 54 can be configured to apply a positive (DC) voltage to the semiconductor electrodes 241 and 242 (relative to the element 12).

[0075] In this implementation, it is also possible to arrange only one of the electrodes 241 or 242. In such an implementation, the drive device comprises a first electrode 22 of the movable element 12 and a second electrode 241 or 242 formed as a doped semiconductor electrode, which is arranged opposite the first electrode 22 and is configured to generate an electrostatic force between the first electrode 22 and the second electrode 241, while generating a first carrier variation zone in the second electrode 241 or 242 for deflecting the movable element 12. For example, a mechanical restoring force can also be used here, for example in a MEMS implementation as a pump.

[0076] However, the embodiments provide for combining a further third electrode, i.e. the electrodes 241 and 242, with the electrode 22. The third electrode can be configured to generate a second carrier variation zone in the third electrode. The third electrode is preferably arranged opposite the electrode 22. The MEMS is configured to alternately generate an electrostatic force between the first electrode 22 and the second electrode 241 and between the first electrode 22 and the third electrode 242, while generating a first carrier variation zone in the second electrode 241 and a second carrier variation zone in the third electrode 242 for deflecting the movable element 12. In this implementation, the first carrier variation zone and the second carrier variation zone are different.

[0077] In this case, the application of a positive or negative constant voltage or DC voltage as described herein should only be understood as an example. The DC voltage, also referred to as constant voltage, does not have to be constant, as long as the voltage at the semiconductor electrodes 241 and 242 is more negative with respect to the movable element 12, since a cumulative zone will form in the semiconductor electrodes 241 and 242 even then and in the case of a variable voltage.

[0078] Figures 9a and 9b show a respective configuration of the semiconductor electrodes 241 and 242 and the movable element 12, which corresponds to Figures 8a and 8b in terms of the doping and all three elements have a corresponding doping type or a corresponding kind of doping. However, due to the voltage variation applied to the elements by means of the actuation device, the space charge zone and the cumulative zone can change, wherein the homogeneity can remain unchanged along the x direction, which is advantageous for the movement of the movable element 12 along this direction.

[0079] Thus, for example, in Figure 8a, the movable element 12 can be positively charged with respect to the electrodes 241 and 242 to obtain a space charge zone 42 at the movable element. In Figure 9a, the movable element 12 can be negatively charged with respect to the electrodes 241 and 242, wherein a cumulative zone 44 can be obtained on the wing.

[0080] In the corresponding Figures 8b and 9b, the p-doped embodiments show the same concept. In Figure 8b, the electrodes of the movable element 12 are negatively charged with respect to the electrodes 241 and 242, wherein a space charge region is obtained on the wings. In Figure 9b, the electrodes of the movable element 12 are positively charged with respect to the electrodes 241 and 242 to obtain a cumulative region 44 at the movable element 12.

[0081] Embodiments of the present application provide a plurality of movable elements which are arranged next to each other along a movement direction x of the movable elements 12. Each movable element can be deflected by a pair of semiconductor electrodes at the cover wafer and / or the bottom wafer. In the context of the embodiments described herein, the movable elements 12 can, but do not necessarily, be movably arranged in a plane with respect to a plane parallel to the substrate plane of the MEMS. For example, the main extension direction of the bottom wafer and / or the cover wafer can be considered as such substrate plane. The movable elements 12 can be movably arranged in a cavity of the substrate of the MEMS. Different wafers or planes or MEMS layers allow for an arrangement in which the first semiconductor electrodes (electrodes of the movable elements) are arranged in a first MEMS layer and the semiconductor electrodes 241 and 242 are arranged in a different second MEMS layer.

[0082] The above-described configuration is particularly preferably applicable to MEMS loudspeakers and / or MEMS microphones, but is not limited thereto, since, for example, pumps, electrostatically driven (such as comb drives) or pressure sensors can also be improved by embodiments.

[0083] Figure 10 A schematic top view of the MEMS 100 according to embodiments is shown. The shown top view can also easily be realized as a side cut view, if desired in the context of MEMS application scenarios.

[0084] The semiconductor electrodes 241 and 242 can be realized as, for example, a finger structure with a plurality of electrode fingers 72, wherein the number of two electrode fingers per semiconductor electrode 241 and 242 is not limited. It is also possible to not implement electrode fingers 72, to implement only one electrode finger or a number greater than two, for example at least three, at least five, at least ten or more.

[0085] Corresponding to the semiconductor electrodes 241 and 242, the movable elements 12 can be formed with electrode fingers 741 to 746, wherein the electrode finger structure of the semiconductor electrodes 241 and 242 and the electrode finger structure of the movable elements 12 can be interlaced with each other, on the one hand. Such a configuration serves to obtain particularly high electrostatic forces, but is not essential for the implementation of the embodiments described herein.

[0086] The semiconductor electrodes 241 and 242 on the one hand and the movable element 12 on the other hand can have different doping types or doping species and can be applied with matching potential mixtures to obtain as precise a deflection of the movable element 12 along the positive and negative x-direction as possible.

[0087] According to a first configuration, therefore, the semiconductor electrodes 241 and 242 can be n-doped and the movable element 12 or its electrodes can be p-doped. In such a configuration, it is advantageous to apply a positive DC voltage 32 to the movable element 12 and to apply AC voltages 361 and 362 to the semiconductor electrodes 241 and 242 which are opposite to each other.

[0088] According to another configuration, the semiconductor electrodes 241 and 242 can be p-doped and the movable element 12 or its electrodes can be n-doped. A negative DC potential 32 can be applied to the movable element 12 and AC potentials 361 and 362 can be applied to the semiconductor electrodes 241 and 242 which are opposite to each other.

[0089] According to an embodiment, the MEMS 100 is part of a MEMS comb drive.

[0090] Furthermore, in the context of the embodiments described herein, it is noted that the movable element 12 can but does not necessarily have to be provided with semiconductor-based electrodes. Rather, for example, also metallized or metallic electrodes can be used, for example by arranging them on the movable element 12 or by forming the movable element 12 in a metallic manner. In such a configuration, the first electrode of the movable element and the second electrode formed as a doped semiconductor electrode and the third electrode formed as a doped semiconductive electrode, for example the semiconductor electrodes 241 and 242, can be arranged similarly to each other as in the other MEMS described herein. The MEMS is configured to generate electrostatic forces alternately between the first electrode and the second electrode on the one hand and between the first electrode and the third electrode on the other hand, while generating a first carrier variation zone in the second electrode and a second carrier variation zone in the third electrode for deflecting the movable element. The variation zones in the semiconductor electrodes can be formed to be identical or different.

[0091] Such a MEMS can easily be combined with the implementation described in connection with the MEMS having three semiconductor electrodes.

[0092] In other words, the embodiments described herein allow to develop MEMS, in particular but not limited to the MEMS described in WO 2022 / 117197 A1. In this regard, according to an embodiment, the AC signal, for example based on a speech signal or a sound signal, is no longer applied to the wing as described in the prior art, wherein a signal variable over time is described as an AC signal.

[0093] While in known systems a positive DC voltage and a negative DC voltage are applied to the first and second cover electrodes (which are considered to be constant), such known MEMS suffer from the disadvantage that the wings and cover electrodes based on their semiconductor properties can be disadvantageous with respect to their actuation. The semiconductor implementation is chosen to allow for example direct wafer bonding, since such a method has a higher alignment accuracy during wafer bonding than other wafer bonding methods. The reason for the disadvantageous actuation is that in semiconductors, when a voltage is applied, a so-called semiconductor effect or field effect occurs, such as in particular for field effect transistors FET. These are based on the fact that either a charge accumulation is formed from mobile charges, electrons or holes, or a space charge region is formed from stationary charges (ion donors / + or ion acceptors / -).

[0094] If a boron-doped silicon semiconductor (p-semiconductor) is taken as an example, then holes / h + Here are the majority carriers (i.e. the multi-carriers), and the electrons e - are the minority carriers (i.e. the few-carriers). In this case, the boron atoms can represent the acceptors / -. The holes and the electrons can be mobile, the boron ions are connected to the silicon host lattice and are therefore stationary.

[0095] If no voltage is applied to such a semiconductor, or the semiconductor is arranged outside an electric field, the mobile charges are randomly or uniformly distributed in the bulk silicon, see Figs. 5a and 6a. However, if a voltage is applied or the semiconductor is in an electric field, the mobile charges will follow the electric field lines, i.e. the holes along the electric lines from + to -, and the electrons also along the electric field lines, but in the opposite direction, from - to +, see Figs. 5b and 6b. Thus, when a positive voltage of e.g. +10 V (see Fig. 6b) is applied (in the form of a voltage U3 approximately), a space charge region 48 (also referred to as a space charge region RLZ) is formed at its surface by the stationary boron ions, and the holes thus migrate from the positively charged boron ions, because charges of the same type repel each other. In the case of a negative voltage (e.g. U2 = -10 V / GND), a + accumulation region of mobile h

[0096] Similar situations can also occur in n-doped semiconductors (e.g. semiconductors doped with phosphorus). Thus, when U2 is applied at e.g. -10 V, a space charge region or a space charge region of stationary P+ ions is formed at the surface, and in the case of an applied U2 voltage of +10 V, an accumulation of mobile e - / electrons is formed at the surface, see Fig. 5b.

[0097] For example in case of a boron-doped p-type semiconductor, if the cap drive is driven as described above, i.e. an AC signal is applied to the wing and a DC+ to the first cap electrode and a DC- to the second cap electrode, a space charge region and an accumulation region are formed simultaneously at the surface of the wing (see Figure 3 ). Since h+ / holes are very mobile, in fact these two regions do not separate as clearly as shown in Figure 3 . In fact, a mixture of space charge region and accumulation region, which changes from smaller x-values to larger x-values, will be established along the x-direction across the wing. This has two main disadvantages. The resulting force acting on the wing will not be ideally linear. Since the space charge region / accumulation region is not equal or acting equally on different sides of the wing, the difference between the following forces is no longer linear: a) "force AC / DC-" and b) "force AC / DC+", resulting in a worsening of the total harmonic distortion THD in the micro-speaker. This means a decrease in sound quality, which is disadvantageous. Furthermore, the mixture of space charge region and accumulation region will lead to an additional capacitance being introduced in the system, i.e. the capacitance of the non-conducting space charge region. This will be connected in series with the air capacitance, i.e. the capacitance between the driving electrodes, which represents the main capacitance of the drive. The additional capacitance in series with the main capacitance reduces the total capacitance of the system and thus also the possible change in capacitance, which can lead to a reduction in the driving force and thus to a smaller deflection of the wing. At the same time, this leads to a reduction in the volume (sound pressure level, SPL).

[0098] The embodiments described herein avoid these disadvantages.

[0099] In this case, the field effect or space charge region and accumulation region are not only formed in the wing (movable element), but also in the electrodes of the cap layer and / or the bottom layer, which causes additional disadvantages in known systems, but provides additional degrees of freedom in the context of the embodiments, as these disadvantages are overcome.

[0100] If the system, i.e. the wing and the electrodes, is formed from metal, a possible ideal state can be achieved, the partial implementation of the electrodes from metal falling within the framework of the embodiments described herein. In metal, no semiconductor effects such as space charge region and accumulation region and changes between these regions occur. Technically, it is relatively complex to produce electrodes on the cap layer and / or the bottom layer and the wing or to arrange metal on the wing and is less preferred in the production process, in particular in silicon-based MEMS.

[0101] The complexity can mainly manifest itself in: a) in the cap drive, since the wing has to be positioned symmetrically between the cap electrode / bottom electrode, a very precise adjustment of less than ±1 pm between cap / bottom and wing is required, and b) the distance between the cap electrode and the wing is relatively small, for example in the order of 100 nm to 200 nm.

[0102] Using metallic materials is technically more difficult to fulfill both requirements compared to semiconductors. This is mainly due to the wafer bonding method that bonds the wing and the cap / bottom wafer together.

[0103] Since the accumulated layers are closer to the properties of metals in terms of conductivity properties (as they have a very high density of mobile carriers), it was initially expected to generate a semiconductor system in which the accumulated regions are formed mainly independent from changes of the voltage or electric field in the system during operation. This can initially be approximated to a state in which all electrodes are made of metal or the semiconductor is omitted.

[0104] Embodiments of the invention change the known systems from the following aspects, for example, the adjustment of the doping of the semiconductor and the actuation scheme (i.e. the setting of the direction of the electric field) is performed in such a way that the space charge regions and the accumulated regions in the system are positively influenced / controlled or taken into account.

[0105] Depending on the application, the system can be planned and configured or designed in such a way that: 1. the loss regions or loss regions / space charge regions RLZ have a minor influence on the system and all involved semiconductors have only accumulated regions at the surface, at least those for the drive; or 2. the involved semiconductors have only loss regions at the surface and no accumulated regions; or 3. a targeted or advantageous selection of a mixture of space charge regions and accumulated regions is used in the system, wherein, for example, each element, electrode of the movable element, first semiconductor electrode and second semiconductor electrode is controlled to a loss region or an accumulated region, but not actuated as in the known concepts so that, for example, the movable element has both a space charge region and an accumulated region at the same time (see Figure 3 ).

[0106] Embodiments, for example embodiments for micro speakers, provide that the system is configured in such a way that the space charge regions have a minor influence on the system and all involved semiconductors have only accumulated regions at the surface, at least in these regions it is used for driving the movable element.

[0107] This can be implemented in particular in such a way that differently doped semiconductors are connected on different sides of the drive, see Figures 7a to 7d. For example, the movable element can be p-type and the cap electrode / bottom electrode can be n-type. Alternatively or additionally, the actuation can be performed in such a way that only accumulated regions always occur on the semiconductor surface, for example in such a way that a control is performed using mutually reversed AC signals so that a constant voltage (for example positive / + voltage) DC+ is applied to the wing and the semiconductor electrodes 241 and 242 at the cap or bottom obtain mutually reversed AC + / AC -signal. In this case, AC + is the mirror inversion of AC - , so that AC + increases with decreasing AC - and vice versa. If the signal DC+ is considered from the absolute value, it is preferably always greater than AC + and AC - so that accumulation regions are generated at the surfaces of the p-semiconductor (e.g. the wing) as well as the n-semiconductor of the cover electrode / bottom electrode at the same time and the electric field between the movable element / wing and the two drive electrodes points in the same direction.

[0108] It is also possible to implement it the other way round, for example, the movable element is n-type and the cover electrode / bottom electrode is p-type. Then, actuation can take place in such a way that the wing obtains a constant negative / -voltage DC-. The cover electrode / bottom electrode is supplied with AC + and AC - signals, wherein their relationship remains unchanged, mirror-inverted. DC- is preferably always negative in the absolute sense (considered with respect to AC + / AC - ), but greater than AC + and AC - in the absolute sense, so that accumulation regions are obtained at the surfaces of the n-type semiconductor of the wing as well as the t-type semiconductor of the cover electrode / bottom electrode at the same time, which means that the electric field between the movable element / wing and the two electrodes 241, 242 points in the same direction.

[0109] Embodiments of the application can be implemented with any electrostatic actuator / sensor, for example a μ-speaker and / or a comb drive. For example, the electrodes 241 and 242 are n-type and the wing is p-type, as shown in Figure 10 and Fig. 7a. Alternatively, the electrodes 241 and 242 can be p-type and the movable element can be n-type, for example as shown in Figure 10 or Fig. 7b.

[0110] In the above examples, it is also possible to select the control such that a space charge region is formed on the surface of all three elements or electrodes, for example as shown in Figs. 7c to 7d. Figs. 7c and 7d show schematic side sectional views of a MEMS according to embodiments, wherein the electrodes 241 and 242 are doped equally on the one hand, but differently to the doping of the semiconductor electrode of the movable element 12, so that in the case of a correct actuation of the semiconductor electrode, all elements form a space charge region 42 or 48.

[0111] In the context of the embodiments described herein, implementations are also possible in which all three electrodes are either n-type semiconductors or p-type semiconductors, see Figs. 8a to 8b and 9a to 9b. In this case, the accumulation region is formed on only one side, either the wing side or the electrode side of the movable element. However, the symmetry with respect to the positive / negative x-direction is maintained.

[0112] Embodiments are also possible in which, for example, the wing and one of the two electrodes 241 / 242 are operated in accumulation mode, while the other one of the electrodes 241, 242 is operated to form a space charge region. In this case, the electrodes 241 and 242 have different kinds of doping with respect to n-type / p-type, wherein the wing can be n-type (e.g. as shown in Fig. 11a) or can be p-type (as shown in Fig. 11b). Figs. 11a to 11b show schematic side cross-sectional views of a MEMS in which the electrodes for driving the movable element form different variations. However, due to the DC actuation, an accumulation region 44 is formed within the movable element, wherein a space charge region can also be provided, and a transition between the accumulation region and the space charge region is avoided (as shown in Fig. 11a) or is formed (as shown in Fig. 11b). Figure 3

[0113] Alternatively, the electrodes 241, 242 can have different kinds of n / p-type doping, and the wing can be p-type.

[0114] The embodiments described herein can likewise be applied to another kind of MEMS, such as a classic comb drive, see Figure 10 , in particular in the case where the combs or electrode receivers comprise or consist of a semiconductor material. In this case, the stator can be regarded as the wing, and the left and right combs are regarded as the electrodes 241, 242.

[0115] The embodiments relate to generating only an accumulation region or only a space charge region on the semiconductor elements of the system. This can occur in the case where the hardware or the MEMS is implemented accordingly with respect to the semiconductor doping type. The elements forming the two sides of the drive can have different doping types, if the wing is p-type, then the cover electrode / bottom electrode is preferably n-type. Alternatively, if the wing is n-type, then the cover electrode / bottom electrode is preferably p-type.

[0116] The embodiments also relate to the actuation, i.e. the software aspect. The actuation is preferably carried out in such a way that a constant DC potential is applied to the wing, and an AC + and AC - signal is applied to the cover electrode / bottom electrode, which is implemented inversely with respect to one another.

[0117] ​Although some aspects have been described in connection with a device, it goes without saying that these aspects also describe the corresponding method, wherein, unless otherwise indicated, the blocks or steps of a device also correspond to a block or a step of a method. Similarly, aspects described in connection with a method also go without saying to describe a corresponding device, wherein, unless otherwise indicated, a block or a step of a method also corresponds to a corresponding block or detail or feature of a device.

[0118] Depending on certain implementation requirements of the inventive methods, embodiments of the application can be implemented in hardware or in software. The implementation can be realized using a digital storage medium, a digital processing medium, or in a propagated data signal with further program code, which is equipped to a computer program product for performing one of the methods when the program code is executed on a computer, where the computer may be a programmable computer system, other programmable computer system or other programmable machine. Therefore, the digital storage medium may be computer-readable. The computer-readable medium may, for example, be a floppy disk, a DVD, a Blu-Ray, a CD, a ROM, a PROM, an EPROM, an EEPROM or a FLASH memory, a memory stick or a similar medium. Further, the computer program product may, for example, be a floppy disk, a DVD, a Blu-Ray, a CD, a ROM, a PROM, an EPROM, an EEPROM or a FLASH memory, a memory stick or a similar medium, on which the computer program code can be stored. The computer program product may, for example, be a floppy disk, a DVD, a Blu-Ray, a CD, a ROM, a PROM, an EPROM, an EEPROM or a FLASH memory, a memory stick or a similar medium, on which the computer program code can be stored.

[0119] Generally, embodiments of the present application can be implemented as a computer program product with a program code, the program code being operative for performing one of the methods when the computer program product runs on a computer. The program code may, for example, be stored on a machine readable carrier.

[0120] Other embodiments comprise the computer program for performing one of the methods described herein, stored on a machine readable carrier. In other words, an embodiment of the inventive method is, therefore, a computer program having a program code for performing one of the methods described herein, when the computer program runs on a computer.

[0121] In other words, an embodiment of the inventive method is, therefore, a computer program having a program code for performing one of the methods described herein, when the computer program runs on a computer. A further embodiment of the inventive methods is, therefore, a data carrier (or a digital storage medium, or a computer-readable medium) comprising, recorded thereon, the computer program for performing one of the methods described herein.

[0122] A further embodiment of the inventive method is, therefore, a data stream or a sequence of signals representing the computer program for performing one of the methods described herein. The data stream or the sequence of signals may, for example, be configured to be transferred via a data communication link, for example via the Internet.

[0123] A further embodiment comprises a processing means, for example a computer, or a programmable logic device, configured or programmed to perform one of the methods described herein.

[0124] Another embodiment comprises a computer having installed thereon the computer program for performing one of the methods described herein.

[0125] In some embodiments, a programmable logic device (e.g., a field programmable gate array (FPGA)) can be used to perform some or all of the functionalities of the methods described herein. In some embodiments, a field programmable gate array can interact with a microprocessor to perform any of the methods described herein. Generally, in some embodiments, the methods are performed by any hardware device. It can be general purpose hardware (such as a computer processor (CPU)) or hardware specific to the methods (e.g., an ASIC).

[0126] The above-described embodiments are merely representative of the principles of the present application. It will be appreciated that modifications and variations of the arrangements and details described herein will be apparent to others skilled in the art. Accordingly, the application is intended to embrace all such modifications and alterations in the details which come within the scope of the following claims.

Claims

1. A MEMS, comprising: a movable element (12); and a drive arrangement (18) comprising a first doped semiconductor electrode (22) of the movable element (12) and a second doped semiconductor electrode (241) arranged opposite the first doped semiconductor electrode (22) and configured to generate an electrostatic force between the first doped semiconductor electrode (22) and the second doped semiconductor electrode (241) while generating a first carrier variation zone in the first doped semiconductor electrode (22) and a second carrier variation zone in the second doped semiconductor electrode (241) for deflecting the movable element (12).

2. The MEMS according to claim 1, further comprising a third doped semiconductor electrode (242) arranged opposite the first doped semiconductor electrode (22) together with the second doped semiconductor electrode, wherein the semiconductor electrodes are configured to alternately generate an electrostatic force between the first doped semiconductor electrode and the second doped semiconductor electrode (241) on the one hand and between the first doped semiconductor electrode and the third doped semiconductor electrode (242) on the other hand while generating the first carrier variation zone in the first doped semiconductor electrode (22), the second carrier variation zone in the second doped semiconductor electrode (241), and a third carrier variation zone in the third doped semiconductor electrode (242) for deflecting the movable element (12); wherein the second carrier variation zone and the third carrier variation zone are of the same kind.

3. The MEMS according to claim 2, wherein the second carrier variation zone and the third carrier variation zone are accumulation zones (44, 52); or wherein the second carrier variation zone and the third carrier variation zone are space charge zones (42, 48).

4. The MEMS according to claim 2, wherein the first carrier variation zone, the second carrier variation zone, and the third carrier variation zone are equal along a longitudinal extension direction (y) or a transverse extension direction (x) of the movable element (12).

5. The MEMS according to claim 2, wherein the first carrier variation zone, the second carrier variation zone, and the third carrier variation zone are of the same kind.

6. The MEMS according to claim 1, comprising an actuation arrangement (54) configured to actuate the drive arrangement (18), wherein the actuation arrangement (54) is configured to apply a direct, DC, voltage to the first doped semiconductor electrode (22) and a first alternating voltage to the second doped semiconductor electrode (241); and a second alternating voltage to a third doped semiconductor electrode (242).

7. The MEMS according to claim 6, wherein the first alternating voltage and the second alternating voltage are opposite. ​ 8. The MEMS according to claim 6, wherein a maximum absolute amplitude of the first alternating voltage and / or the second alternating voltage is smaller than an absolute amplitude of the direct, DC, voltage.

9. The MEMS according to claim 2, wherein at least two elements of the group of the first doped semiconductor electrode (22), the second doped semiconductor electrode (241) and the third doped semiconductor electrode (242) have a different doping type.

10. The MEMS according to claim 9, wherein the first doped semiconductor electrode (22) has a different doping type with respect to the second doped semiconductor electrode and / or the third doped semiconductor electrode (242).

11. The MEMS according to claim 2, wherein the first doped semiconductor electrode (22), the second doped semiconductor electrode (241) and the third doped semiconductor electrode (242) have the same doping type.

12. The MEMS according to claim 11, wherein the first carrier change region is of a different kind than the second carrier change region and the third carrier change region.

13. The MEMS according to claim 11, wherein the MEMS has an actuation device (54) configured to actuate the drive device (18); wherein the semiconductor electrode is n-doped and the actuation device (54) is configured to apply a negative direct, DC, voltage to the first doped semiconductor electrode (22); or wherein the semiconductor electrode is p-doped and the actuation device (54) is configured to apply a positive direct, DC, voltage to the first doped semiconductor electrode (22).

14. The MEMS according to claim 1, comprising a plurality of movable elements (12) arranged next to each other along a movement direction (x) of the movable elements (12).

15. The MEMS according to claim 1, wherein the movable element (12) is movably arranged in a plane with respect to a plane parallel to a substrate plane of the MEMS (x / y).

16. The MEMS according to claim 1, wherein the movable element (12) is arranged in a cavity of a substrate of the MEMS.

17. The MEMS according to claim 1, wherein the first doped semiconductor electrode (22) is arranged in a first MEMS layer and the second doped semiconductor electrode (241) and the third doped semiconductor electrode are arranged in a second MEMS layer.

18. The MEMS according to claim 17, the MEMS being part of a MEMS loudspeaker.

19. The MEMS according to claim 1, wherein the first doped semiconductor electrode (22) is arranged between the second doped semiconductor electrode (241) and the third doped semiconductor electrode (242).

20. The MEMS according to claim 19, the MEMS being part of a MEMS comb drive.

21. The MEMS according to claim 1, further comprising a third doped semiconductor electrode (242) arranged opposite to the first doped semiconductor electrode (22) together with the second doped semiconductor electrode, wherein the semiconductor electrodes are configured to alternately generate electrostatic forces between the first doped semiconductor electrode and the second doped semiconductor electrode (241) and between the first doped semiconductor electrode and the third doped semiconductor electrode (242) while generating the first carrier variation zone in the first doped semiconductor electrode (22), the second carrier variation zone in the second doped semiconductor electrode (241), and a third carrier variation zone in the third doped semiconductor electrode (242) for deflecting the movable element (12); wherein the second carrier variation zone and the third carrier variation zone are of the same kind; wherein the first doped semiconductor electrode (22), the second doped semiconductor electrode (241), and the third doped semiconductor electrode (242) have the same doping type; wherein the MEMS has an actuation device (54) configured to actuate the drive device (18); and wherein the semiconductor electrodes are n-doped and the actuation device (54) is configured to apply a negative direct current, DC, voltage to the first doped semiconductor electrode (22); or wherein the semiconductor electrodes are p-doped and the actuation device (54) is configured to apply a positive direct current, DC, voltage to the first doped semiconductor electrode (22).

22. A MEMS, comprising: a movable element (12); and a drive device (18) comprising a first electrode (22) of the movable element (12) and a second electrode (241) formed as a doped semiconductor electrode arranged opposite to the first electrode (22) and configured to generate an electrostatic force between the first electrode (22) and the second electrode (241) while generating a first carrier variation zone in the second electrode (241) and for deflecting the movable element (12).

23. The MEMS according to claim 22, further comprising: a third electrode (242) formed as a doped semiconductor electrode arranged opposite to the first electrode (22) together with the second electrode and configured to generate a second carrier variation zone in the third electrode; 24. The MEMS according to claim 23, wherein the first, second, and third electrodes are of the same doping type. wherein said MEMS is configured to generate electrostatic forces alternately between said first electrode (22) and said second electrode (241) and between said first electrode (22) and said third electrode (242), while generating said first carrier change region in said second electrode (241) and said second carrier change region in said third electrode (242), for deflecting said movable element (12); wherein said first carrier change region and said second carrier change region are different.

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