Patent ID: 12219333

DETAILED DESCRIPTION

The following detailed description of certain embodiments presents various descriptions of specific embodiments. However, the innovations described herein can be embodied in a multitude of different ways, for example, as defined and covered by the claims. In this description, reference is made to the drawings were like reference numerals can indicate identical or functionally similar elements. It will be understood that elements illustrated in the figures are not necessarily drawn to scale. Moreover, it will be understood that certain embodiments can include more elements than illustrated in a drawing and/or a subset of the elements illustrated in a drawing. Further, some embodiments can incorporate any suitable combination of features from two or more drawings.

Piezoelectric MEMS Microphone

FIGS.1A-1Bshow a conventional piezoelectric microelectromechanical systems (MEMS) microphone10(hereinafter the “microphone”). The microphone10has a substrate12. The substrate12is optionally made of Silicon and may optionally have additional dielectric, metallic or semiconductor films deposited on it. The microphone10can have one or more piezoelectric sensors14(hereinafter “sensors”) anchored to the substrate12in cantilever form with a gap16between adjacent sensors14. The microphone10converts an acoustic signal to an electrical signal when a sound wave vibrates the sensors14. The sensors14can be made from one or more layers of material. Optionally, the sensors14can be made at least in part of Aluminum Nitride (AlN). In another implementation, the sensors14can optionally be made at least in part of Scandium Aluminum Nitride (ScAlN) or other piezoelectric materials. The sensors14can include an electrode, which can optionally be made of molybdenum (Mo), titanium nitride (TiN), platinum (Pt) or ruthenium (Ru), in some implementations. The gaps16between the sensors14allow the sensors14to freely move, for airflow F to pass therethrough, and balance the pressure between both sides of the sensors14. The gap16can be about 100-500 nm wide. The sensors14are preferably planar (e.g., flat), but are generally not completely flat due to a material internal stress gradient in the sensors14.

FIG.1Cshows another embodiment of a cantilevered piezoelectric sensor14attached to the substrate. The piezoelectric sensor14is a multilayer cantilevered structure with one or more piezoelectric layers11(e.g., two piezoelectric layers) and one or more conductive layers17(e.g., three metal electrode layers). As shown, in one example each piezoelectric layer11can be interposed between two conductive layers17.

FIG.1Dshows another embodiment of a cantilevered piezoelectric sensor14attached to the substrate. The piezoelectric sensor14is a multilayer cantilevered structure with one or more piezoelectric layers11(e.g., one piezoelectric layer), one or more conductive layers17(e.g., two metal electrode layers), and one or more elastic layers13. As shown, in one example a piezoelectric layer11can be interposed between two conductive layers17and the elastic layer13can be a bottom layer of the cantilevered structure.

Acoustic Devices with Increased Sensitivity

With reference toFIGS.2A-13, the inventors have identified that widening the tips of cantilevered sensors in a piezoelectric MEMS microphone relative to the anchored end of the sensors can advantageously improve the output energy of the piezoelectric MEMS microphone, thereby improving the sensitivity of the piezoelectric MEMS microphone or allowing a reduction in the size of the piezoelectric MEMS microphone while providing the same output energy.

FIG.2Ashows a schematic plan view of a cantilevered sensor14A. The sensor14A defines a beam D that has a proximal portion or end A anchored to the substrate S in cantilever form (e.g., so that there is a gap between adjacent sensors14A). The proximal portion or end A is linear. The beam D extends to a distal tip B at a free end (e.g., unsupported end). The distal tip B is linear. As shown inFIG.2A, the distal tip B has a width (in plan view) greater than a width of the proximal portion or end A. The side edges (e.g., opposite side edges) of the beam D extend linearly (e.g., a long a straight line) between the proximal portion or end A and the distal tip B. As shown inFIG.2A, the beam D has a width at a location distal of the proximal portion A (e.g., at line C parallel to the proximal portion A) that is greater than the width at the proximal portion A. The beam D is symmetrical about a centerline of the beam D extending from the proximal portion to the distal tip B. In the illustrated implementation, the beam D has a generally trapezoidal shape (e.g., isosceles trapezoid).

The sensor14A is preferably planar (e.g., flat), but are generally not completely flat due to a material internal stress gradient in the sensor14A. The sensor14A can be made from one or more layers of material. Optionally, the sensor14A can be made at least in part of Aluminum Nitride (AlN). In another implementation, the sensor14A can optionally be made at least in part of Scandium Aluminum Nitride (ScAlN). The sensor14A can include an electrode, which can optionally be made of molybdenum (Mo), titanium nitride (TiN), platinum (Pt) or ruthenium (Ru), in some implementations. The gaps between the sensors14A (as further discussed below) allow the sensors14A to freely move, for airflow F to pass therethrough, and balance the pressure between both sides of the sensors14A. Such gaps between the sensors14A can be about 100-500 nm wide.

FIG.2Bshows a schematic plan view of a cantilevered sensor14B. Some of the features of the sensor14B are similar to features of the sensor14A inFIG.2A. Thus, reference identifiers used to designate the various components of the sensor14B are identical to those used for identifying the corresponding components of the sensor14A inFIG.2A. Therefore, the structure and description for the various features of the sensor14A inFIG.2Aare understood to also apply to the corresponding features of the sensor14B inFIG.2B, except as described below.

The sensor14B differs from the sensor14A in that a width of the beam D decreases linearly between the proximal portion A and an intermediate portion, before the width increases linearly to the distal tip B. As shown inFIG.2B, the beam D has a width at a location distal of the proximal portion A (e.g., at line C parallel to the proximal portion A) that is greater than the width at the proximal portion A. The beam D is symmetrical about a centerline of the beam D and the width (in plan view) of the distal tip B is greater than the width of the proximal portion or end A.

FIG.2Cshows a schematic plan view of a cantilevered sensor14C. Some of the features of the sensor14C are similar to features of the sensor14A inFIG.2A. Thus, reference identifiers used to designate the various components of the sensor14C are identical to those used for identifying the corresponding components of the sensor14A inFIG.2A. Therefore, the structure and description for the various features of the sensor14A inFIG.2Aare understood to also apply to the corresponding features of the sensor14C inFIG.2C, except as described below.

The sensor14C differs from the sensor14A in that the proximal portion or end A has a curved shape, while the distal tip B has a linear shape. The width of the beam D increases linearly from the proximal portion or end A to the distal tip B. As shown inFIG.2C, the beam D has a width at a location distal of the proximal portion A (e.g., at line C parallel to the proximal portion A) that is greater than the width at the proximal portion A. The width (in plan view) of the distal tip B is greater than the width (e.g., tracing the curved line) of the proximal portion or end A. The beam D is symmetrical about a centerline of the beam D.

FIG.2Dshows a schematic plan view of a cantilevered sensor14D. Some of the features of the sensor14D are similar to features of the sensor14A inFIG.2A. Thus, reference identifiers used to designate the various components of the sensor14D are identical to those used for identifying the corresponding components of the sensor14A inFIG.2A. Therefore, the structure and description for the various features of the sensor14A inFIG.2Aare understood to also apply to the corresponding features of the sensor14D inFIG.2D, except as described below.

The sensor14D differs from the sensor14A in that the proximal portion or end A has a curved shape, and in that the distal tip B has a curved shape. The width of the beam D increases linearly from the proximal portion or end A to the distal tip B. As shown inFIG.2D, the beam D has a width at a location distal of the proximal portion A (e.g., at line C parallel to the proximal portion A) that is greater than the width at the proximal portion. The width (in plan view, tracing the curved line) of the distal tip B is greater than the width (e.g., tracing the curved line) of the proximal portion or end A. The beam D is symmetrical about a centerline of the beam D.

FIG.2Eshows a schematic plan view of a cantilevered sensor14E. Some of the features of the sensor14E are similar to features of the sensor14A inFIG.2A. Thus, reference identifiers used to designate the various components of the sensor14E are identical to those used for identifying the corresponding components of the sensor14A inFIG.2A. Therefore, the structure and description for the various features of the sensor14A inFIG.2Aare understood to also apply to the corresponding features of the sensor14E inFIG.2E, except as described below.

The sensor14E differs from the sensor14A in that the proximal portion or end A has a curved shape, while the distal tip B has a linear shape. The width of the beam D increases linearly from the proximal portion or end A to the distal tip B. As shown inFIG.2E, the beam D has a width at a location distal of the proximal portion A (e.g., at line C parallel to a virtual line between ends of the proximal portion A) that is greater than the width at the proximal portion A. The width (in plan view) of the distal tip B is greater than the width (e.g., tracing a virtual line between end points of the curved line) of the proximal portion or end A. The beam D is symmetrical about a centerline of the beam D.

FIG.2Fshows a schematic plan view of a cantilevered sensor14F. Some of the features of the sensor14F are similar to features of the sensor14A inFIG.2A. Thus, reference identifiers used to designate the various components of the sensor14F are identical to those used for identifying the corresponding components of the sensor14A inFIG.2A. Therefore, the structure and description for the various features of the sensor14A inFIG.2Aare understood to also apply to the corresponding features of the sensor14F inFIG.2C, except as described below.

The sensor14F differs from the sensor14A in that the proximal portion or end A has an S-curved shape, while the distal tip B has a linear shape. The width of the beam D increases linearly from the proximal portion or end A to the distal tip B. As shown inFIG.2F, the beam D has a width at a location distal of the proximal portion A (e.g., at line C parallel to a virtual line between end points of the proximal portion A) that is greater than the width at the proximal portion A. The width (in plan view) of the distal tip B is greater than the width (e.g., tracing a virtual line between end points of the curved line) of the proximal portion or end A. The beam D is asymmetrical about a centerline of the beam D.

FIG.3Ashows a schematic plan view of a cantilevered sensor14G. Some of the features of the sensor14G are similar to features of the sensor14A inFIG.2A. Thus, reference identifiers used to designate the various components of the sensor14G are identical to those used for identifying the corresponding components of the sensor14A inFIG.2A. Therefore, the structure and description for the various features of the sensor14A inFIG.2Aare understood to also apply to the corresponding features of the sensor14G inFIG.3A, except as described below.

The sensor14G differs from the sensor14A in that the side edges (e.g., opposite side edges) of the beam D extend along a curved line between the proximal portion or end A and the distal tip B. In the illustrated embodiment, the side edge S of the beam D extends along concave curved lines between the proximal portion A and the distal tip B. In other implementations, the side edges of the beam D can extend along convex curved lines between the proximal portion A and the distal tip B. The width of the beam D increases from the proximal portion or end A to the distal tip B. As shown inFIG.3A, the beam D has a width at a location distal of the proximal portion A (e.g., at line parallel to the proximal portion A) that is greater than the width at the proximal portion A. The width (in plan view) of the distal tip B is greater than the width of the proximal portion or end A. The beam D is symmetrical about a centerline of the beam D.

FIG.3Bshows a schematic plan view of a cantilevered sensor14H. Some of the features of the sensor14H are similar to features of the sensor14A inFIG.2A. Thus, reference identifiers used to designate the various components of the sensor14H are identical to those used for identifying the corresponding components of the sensor14A inFIG.2A. Therefore, the structure and description for the various features of the sensor14A inFIG.2Aare understood to also apply to the corresponding features of the sensor14H inFIG.3B, except as described below.

The sensor14H differs from the sensor14A in that one of the side edges of the beam D extends linearly (e.g., along a straight line, at a non-perpendicular angle relative to a plane defined by the proximal portion or end A) between the proximal portion or end A and the distal tip B, and the other of the side edges (e.g., opposite side edge) of the beam D extends along a curved line (e.g., concave, convex) between the proximal portion or end A and the distal tip B. The width of the beam D increases from the proximal portion or end A to the distal tip B. As shown inFIG.3B, the beam D has a width at a location distal of the proximal portion A (e.g., at line parallel to the proximal portion A) that is greater than the width at the proximal portion A. The width (in plan view) of the distal tip B is greater than the width of the proximal portion or end A. The beam D is asymmetrical about a centerline of the beam D.

FIG.3Cshows a schematic plan view of a cantilevered sensor14I. Some of the features of the sensor14I are similar to features of the sensor14A inFIG.2A. Thus, reference identifiers used to designate the various components of the sensor14I are identical to those used for identifying the corresponding components of the sensor14A inFIG.2A. Therefore, the structure and description for the various features of the sensor14A inFIG.2Aare understood to also apply to the corresponding features of the sensor14I inFIG.3C, except as described below.

The sensor14I differs from the sensor14A in that one of the side edges of the beam D extends linearly (e.g., along a straight line perpendicular to a plane defined by the proximal portion or end A) between the proximal portion or end A and the distal tip B, and the other of the side edges (e.g., opposite side edge) of the beam D extends along a curved line (e.g., concave, convex) between the proximal portion or end A and the distal tip B. The width of the beam D increases from the proximal portion or end A to the distal tip B. As shown inFIG.3C, the beam D has a width at a location distal of the proximal portion A (e.g., at line parallel to the proximal portion A) that is greater than the width at the proximal portion A. The width (in plan view) of the distal tip B is greater than the width of the proximal portion or end A. The beam D is asymmetrical about a centerline of the beam D.

FIG.3Dshows a schematic plan view of a cantilevered sensor14J. Some of the features of the sensor14J are similar to features of the sensor14A inFIG.2A. Thus, reference identifiers used to designate the various components of the sensor14J are identical to those used for identifying the corresponding components of the sensor14A inFIG.2A. Therefore, the structure and description for the various features of the sensor14A inFIG.2Aare understood to also apply to the corresponding features of the sensor14J inFIG.3D, except as described below.

The sensor14J differs from the sensor14A in that the side edges (e.g., opposite side edges) of the beam D extend along a curved line between the proximal portion or end A and the distal tip B. In the illustrated embodiment, the side edges of the beam D extend along concave curved lines between the proximal portion A and the distal tip B. In other implementations, the side edges of the beam D can extend along convex curved lines between the proximal portion A and the distal tip B. The width of the beam D decreases in a curved manner to an intermediate portion and increases in a curved manner from the intermediate portion to the distal tip B. As shown inFIG.3D, the beam D has a width at a location distal of the proximal portion A (e.g., at line parallel to the proximal portion A) that is greater than the width at the proximal portion A. The width (in plan view) of the distal tip B is greater than the width of the proximal portion or end A. The beam D is symmetrical about a centerline of the beam D.

FIG.3Eshows a schematic plan view of a cantilevered sensor14K. Some of the features of the sensor14K are similar to features of the sensor14A inFIG.2A. Thus, reference identifiers used to designate the various components of the sensor14K are identical to those used for identifying the corresponding components of the sensor14A inFIG.2A. Therefore, the structure and description for the various features of the sensor14A inFIG.2Aare understood to also apply to the corresponding features of the sensor14K inFIG.3E, except as described below.

The sensor14K differs from the sensor14A in that one of the side edges of the beam D extends linearly (e.g., along a straight line, at a non-perpendicular angle relative to a plane defined by the proximal portion or end A) between the proximal portion or end A and the distal tip B, and the other of the side edges (e.g., opposite side edge) of the beam D extends along a curved line between the proximal portion or end A and the distal tip B. In the illustrated embodiment, the side edge of the beam D extends along concave curved line between the proximal portion A and the distal tip B. In other implementations, the side edge of the beam D can extend along convex curved line between the proximal portion A and the distal tip B. The width of the beam D decreases between the proximal portion or end A and an intermediate portion and then increases from the intermediate portion to the distal tip B. As shown inFIG.3E, the beam D has a width at a location distal of the proximal portion A (e.g., at line parallel to the proximal portion A) that is greater than the width at the proximal portion A. The width (in plan view) of the distal tip B is greater than the width of the proximal portion or end A. The beam D is asymmetrical about a centerline of the beam D.

FIG.3Fshows a schematic plan view of a cantilevered sensor14L. Some of the features of the sensor14L are similar to features of the sensor14A inFIG.2A. Thus, reference identifiers used to designate the various components of the sensor14L are identical to those used for identifying the corresponding components of the sensor14A inFIG.2A. Therefore, the structure and description for the various features of the sensor14A inFIG.2Aare understood to also apply to the corresponding features of the sensor14L inFIG.3F, except as described below.

The sensor14L differs from the sensor14A in that one of the side edges of the beam D extends linearly (e.g., along a straight line perpendicular relative to a plane defined by the proximal portion or end A) between the proximal portion or end A and the distal tip B, and the other of the side edges (e.g., opposite side edge) of the beam D extends along a curved line between the proximal portion or end A and the distal tip B. In the illustrated embodiment, the side edge of the beam D extends along concave curved line between the proximal portion A and the distal tip B. In other implementations, the side edge of the beam D can extend along convex curved line between the proximal portion A and the distal tip B. The width of the beam D decreases between the proximal portion or end A and an intermediate portion and then increases from the intermediate portion to the distal tip B. As shown inFIG.3F, the beam D has a width at a location distal of the proximal portion A (e.g., at line parallel to the proximal portion A) that is greater than the width at the proximal portion A. The width (in plan view) of the distal tip B is greater than the width of the proximal portion or end A. The beam D is asymmetrical about a centerline of the beam D.

With reference to the sensors14G to14L inFIGS.3A-3F, though the distal tip B is shown as being linear (e.g., extending along a straight line), in other implementations the distal tip B can instead be curved (e.g., define a concave or convex edge).

FIG.4shows a schematic top view of a piezoelectric MEMS microphone10A with a substrate12A. The cantilevered sensor14A (e.g., described above with respect toFIG.2A) is attached via an anchor S to the substrate12A, and a cantilevered sensor14M attached via an anchor S to the substrate12A and arranged opposite to the cantilevered sensor14A. The cantilevered sensor14M is similar to the cantilevered sensor14G (e.g., described above with respect toFIG.3A), except that the distal tip surface includes a curved (e.g., concave) surface. Gaps16A (e.g., etched in the substrate12A) between the cantilevered sensors14A,14M and the substrate12A and/or between the distal tips of the cantilevered sensors14A,14M can advantageously be sized to increase the −3 dB roll off to inhibit (e.g., reduce) a risk of damage to the MEMS microphone from vocal plosives, which occur at low frequencies.

FIG.5Ashows a schematic perspective view of a cantilevered sensor15A that extends between a proximal portion or end A that can be anchored to a substrate (e.g., of a piezoelectric MEMS microphone) and a distal tip or end B. The width of the proximal portion A is greater than the width of the distal tip B. The cantilevered sensor15A has a length of 400 μm, the proximal portion A has a width of 300 μm and the distal tip B has a width of 100 μm.FIG.5Bshows a schematic perspective view of a cantilevered sensor15B that extends between a proximal portion or end A that can be anchored to a substrate (e.g., of a piezoelectric MEMS microphone) and a distal tip or end B. The width of the proximal portion A is equal to the width of the distal tip B. The cantilevered sensor15B has a length of 400 μm, and the proximal portion A and distal tip B both have a width of 300 μm.FIG.5Cshows a schematic perspective view of a cantilevered sensor15C that extends between a proximal portion or end A that can be anchored to a substrate (e.g., of a piezoelectric MEMS microphone) and a distal tip or end B. The width of the proximal portion A is smaller than the width of the distal tip B. The cantilevered sensor15C has a length of 400 μm, the proximal portion A has a width of 300 μm and the distal tip B has a width of 500 μm. The cantilevered sensors15A,15B,15C include two piezoelectric layers of Aluminum Nitride (AlN), each 300 nm thick and three layers of ruthenium (Ru) as electrodes, each 30 nm thick.

FIG.6is a graph of output voltage (in mV) versus width (in μm) for the distal tip B, for cantilevered sensors extending between a proximal portion A that is anchored (e.g., on a substrate) and the distal tip B (e.g., at a free or unsupported end of the cantilevered sensor), including cantilevered sensors15A-15C. As shown in the graph, output voltage for the cantilevered sensor advantageously increases as the width of the distal tip B of the cantilevered sensor increases (e.g., relative to the width of the proximal portion or end A that is anchored to the substrate).

FIG.7is a graph of bandwidth (in Hz) versus width (in μm) for the distal tip B, for cantilevered sensors extending between a proximal portion A that is anchored (e.g., on a substrate) and the distal tip B (e.g., at a free or unsupported end of the cantilevered sensor), including cantilevered sensors15A-15C. As shown in the graph, bandwidth for the cantilevered sensor decreases as the width of the distal tip B of the cantilevered sensor increases (e.g., relative to proximal portion A that is anchored to the substrate). The cantilevered sensors15A-15C can advantageously be designed to meet a bandwidth requirement while achieving increased output energy by increasing the width of the distal tip of the cantilevered sensor relative to its proximal portion A or anchored end.

FIG.8Ashows a schematic perspective view of a cantilevered sensor15D that extends between a proximal portion or end A that can be anchored to a substrate (e.g., of a piezoelectric MEMS microphone) and a distal tip or end B. The width of the proximal portion A is smaller than the width of the distal tip B.FIG.8Bshows a schematic perspective view of a cantilevered sensor15E that extends between a proximal portion or end A that can be anchored to a substrate (e.g., of a piezoelectric MEMS microphone) and a distal tip or end B. The width of the proximal portion A is greater than the width of the distal tip B. The cantilevered sensors15D and15E have the same device area.

FIG.9is a graph of output energy (in Joules) versus device area (in m2) for the distal tip B, for cantilevered sensors extending between a proximal portion A anchored (e.g., on a substrate) and the distal tip B (e.g., at a free or unsupported end of the cantilevered sensor), including cantilevered sensors15D-15E. As shown in the graph, the output energy for the cantilevered sensor advantageously is greater (e.g., more than ten times higher) where the distal tip is wide (e.g., has a greater width relative to proximal portion A that is anchored), as compared with a cantilevered sensor where the distal tip is narrow (e.g., smaller width relative to proximal portion A that is anchored), where the cantilevered sensors have the same device area.

FIG.10is a graph of bandwidth (in kHz) versus device area (in m2) for the distal tip B, for cantilevered sensors extending between a proximal portion A that is anchored (e.g., on a substrate) and the distal tip B (e.g., at a free or unsupported end of the cantilevered sensor), including cantilevered sensors15D-15E. As shown in the graph, bandwidth for the cantilevered sensor is lower when the distal tip is wide (e.g., has a greater width), as compared with a cantilevered sensor where the distal tip is narrow (e.g., smaller width), where the cantilevered sensors have the same device area.

FIG.11shows one configuration (e.g., area-efficient configuration) of a piezoelectric MEMS microphone10B with cantilevered sensors14A (e.g., described above in connection withFIG.2A) having anchored ends A on a substrate12B. One or more pairs (e.g., three pairs) of the cantilevered sensors14A can be arranged opposite each other (e.g., so that the distal tip or free unsupported end of the sensors14A face each other). Gaps16B (e.g., etched trenches in the substrate12B) between the cantilevered sensors14A and the substrate12B or between the distal tips of the sensors14A allow the sensors14A to freely move and for airflow to pass therethrough. Though the arrangement inFIG.11includes the cantilevered sensors14A, one of skill in the art will recognize that the arrangement can instead include any of the other cantilevered sensor designs disclosed here (e.g., cantilevered sensors14B to14M). Advantageously, the configuration inFIG.11can increase output energy for the piezoelectric MEMS microphone.

FIG.12shows another configuration (e.g., area-efficient configuration) of a piezoelectric MEMS microphone10C with cantilevered sensors14A (e.g., described above in connection withFIG.2A) having anchored ends A on a substrate12C. The cantilevered sensors14A can be arranged in one or more (e.g., two) rows, where adjacent cantilevered sensors14A can alternate in orientation along the row (e.g., anchored end A of one sensor14A generally aligned with a distal tip of an adjacent sensor14A). Gaps16C (e.g., etched trenches in the substrate12C) between the cantilevered sensors14A and the substrate12C allow the sensors14A to freely move and for airflow to pass therethrough. Though the arrangement inFIG.12includes the cantilevered sensors14A, one of skill in the art will recognize that the arrangement can instead include any of the other cantilevered sensor designs disclosed here (e.g., cantilevered sensors14B to14M). Advantageously, the configuration inFIG.12can increase output energy for the piezoelectric MEMS microphone.

FIG.13shows another configuration (e.g., area-efficient configuration) of a piezoelectric MEMS microphone10D with cantilevered sensors14A (e.g., described above in connection withFIG.2A) having anchored ends A on a substrate12D. The cantilevered sensors14A can be arranged in a circular manner, where the anchored ends A of the cantilevered sensors14A generally define a first circular shape, and the distal tips of the cantilevered sensors14A generally define a second circular shape that is larger than the first circular shape. Gaps16D (e.g., etched trenches in the substrate12D) between the cantilevered sensors14A and the substrate12D allow the sensors14A to freely move and for airflow to pass therethrough. Though the arrangement inFIG.13includes the cantilevered sensors14A, one of skill in the art will recognize that the arrangement can instead include any of the other cantilevered sensor designs disclosed here (e.g., cantilevered sensors14B to14M). Advantageously, the configuration inFIG.13can increase output energy for the piezoelectric MEMS microphone.

One or more (e.g., a plurality of) cantilevered sensors disclosed herein (e.g., sensors14A-14M) can be incorporated into a piezoelectric MEMS microphone, for example arranged in area-efficient configurations, such as those illustrated inFIGS.4and11-13. For example,FIG.14shows a two-port microphone module150that has a piezoelectric MEMS microphone package (the “PMM package”)160coupled to (e.g., mounted on) a printed circuit board154and enclosed by a microphone enclosure152, a cavity153defined between the microphone enclosure152and the PMM package160. The PMM package160has a package substrate162on which a piezoelectric MEMS microphone170and one or more application specific integrated circuit (ASIC) modules180are mounted. The ASIC module(s)180are electrically connected to the piezoelectric MEMS microphone170and the package substrate162. The piezoelectric MEMS microphone170includes a substrate172attached to the package substrate162and one or more (e.g., multiple) cantilevered sensors174attached to the substrate172so as to define a front cavity175between the package substrate162and the cantilevered sensors174. The cantilevered sensor(s)174can have any configuration disclosed herein (e.g., for the cantilevered sensors14A-14M), and can be arranged in area-efficient configurations (e.g., as illustrated inFIGS.4and11-13). The PMM package160includes a package cap185that encloses the piezoelectric MEMS microphone170and ASIC module(s)180and is disposed over the package substrate162, where a rear cavity187is defined between the package cap185and the piezoelectric MEMS microphone170.

Sound enters the microphone module150along a first path through a first sound inlet O1in the microphone enclosure152, printed circuit board154and package substrate162and into the front cavity175. Sound also enters the microphone module150along a second path through a second sound inlet O2in the microphone enclosure152, into the cavity153, and through a port O3in the package cap185and into the rear cavity187. Advantageously, the cantilevered sensors174in the two-port microphone module150exhibit greater compliance and sensitivity (e.g., exhibit larger deflection for same level of sound pressure), reduce low frequency roll-off, and inhibit high degradation because avoid back volume.

FIG.15shows different polar responses that can be achieved based on different designs of the microphone module150(e.g., based on the design of the enclosure, such as acoustic resistance along the travel path, rear capsule volume and rear sound port dimensions, to achieve desired directionality for frequencies of interest).

The cantilevered sensors described herein (e.g., cantilevered sensors14A-14M shown inFIGS.2A-4) for piezoelectric MEMS microphones advantageously provide increased performance (e.g., increased output energy) for the same device area as conventional cantilevered sensors. Alternatively, the cantilevered sensors described herein (e.g., cantilevered sensors14A-14M shown inFIGS.2A-4) for piezoelectric MEMS microphones advantageously provide the same performance (e.g., output energy) as conventional cantilevered sensors in a smaller device area, allowing for the reduction in size of the piezoelectric MEMS microphone.

FIG.16is a schematic diagram of an audio subsystem300. The audio subsystem300can include one or more microphones10A,10B,10C,10D,170. In one implementation, at least one of the microphone(s)10A,10B,10C,10D,170is a piezoelectric MEMS microphone. The microphone(s)10A,10B,10C,10D,170can communicate with an audio codec301, which can control the operation of the microphone(s)10A,10B,10C,10D,170. The audio codec301can also communicate with a speaker302and control the operation of the speaker302.

FIG.17Ais a schematic diagram of an electronic device200that includes the audio subsystem300. The electronic device200can optionally have one or more of a processor210, a memory220, a user interface230, a battery240(e.g., direct current (DC) battery) and a power management module250. Other additional components, such a display and keyboard can optionally be connected to the processor210. The battery240can provide power to the electronic device200.

It should be noted that, for simplicity, only certain components of the electronic device200are illustrated herein. The control signals provided by the processor210control the various components within the electronic device200.

The processor210communicates with the user interface230to facilitate processing of various user input and output (I/O), such as voice and data. As shown inFIG.17A, the processor210communicates with the memory220to facilitate operation of the electronic device200.

The memory220can be used for a wide variety of purposes, such as storing data and/or instructions to facilitate the operation of the electronic device200and/or to provide storage of user information.

The power management system or module250provides a number of power management functions of the electronic device200. In certain implementations, the power management system250includes a PA supply control circuit that controls the supply voltages of power amplifiers. For example, the power management system250can change the supply voltage(s) provided to one or more power amplifiers to improve efficiency.

As shown inFIG.17A, the power management system250receives a battery voltage from the battery240. The battery240can be any suitable battery for use in the electronic device200, including, for example, a lithium-ion battery.

FIG.17Bis a schematic diagram of a wireless electronic device200′ The wireless electronic device200′ is similar to the electronic device200inFIG.17A. Thus, reference numerals used to designate the various components of the wireless electronic device200′ are identical to those used for identifying the corresponding components of the electronic device200inFIG.17A. Therefore, the structure and description above for the various features of the electronic device200inFIG.17Aare understood to also apply to the corresponding features of the wireless electronic device200′ inFIG.17B, except as described below.

The wireless electronic device200′ differs from the electronic device200in that it also includes a transceiver260that communicates (e.g., two-way communication) with the processor210. Signals, data and/or information received (e.g., wirelessly) by the transceiver260(e.g., from a remote electronic device, such a smartphone, tablet computer, etc.) is communicated to the processor210, and signals, data and/or information provided by the processor is communicated (e.g., wirelessly) by the transceiver260(e.g., to a remote electronic device). Further, the function of the transceiver260can be integrated into separate transmitter and receiver components.

The wireless electronic device200′ can be used to communicate using a wide variety of communications technologies, including, but not limited to, 2G, 3G, 4G (including LTE, LTE-Advanced, and LTE-Advanced Pro), 5G NR, WLAN (for instance, Wi-Fi), WPAN (for instance, Bluetooth and ZigBee), WMAN (for instance, WiMax), and/or GPS technologies.

The transceiver260generates RF signals for transmission and processes incoming RF signals received from antennas. It will be understood that various functionalities associated with the transmission and receiving of RF signals can be achieved by one or more components that are collectively represented inFIG.17Bas the transceiver260. In one example, separate components (for instance, separate circuits or dies) can be provided for handling certain types of RF signals.

The processor210provides the transceiver260with digital representations of transmit signals, which the transceiver260processes to generate RF signals for transmission. The processor210also processes digital representations of received signals provided by the transceiver260.

While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the disclosure. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions and changes in the systems and methods described herein may be made without departing from the spirit of the disclosure. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the disclosure. Accordingly, the scope of the present inventions is defined only by reference to the appended claims.

Features, materials, characteristics, or groups described in conjunction with a particular aspect, embodiment, or example are to be understood to be applicable to any other aspect, embodiment or example described in this section or elsewhere in this specification unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The protection is not restricted to the details of any foregoing embodiments. The protection extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Furthermore, certain features that are described in this disclosure in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations, one or more features from a claimed combination can, in some cases, be excised from the combination, and the combination may be claimed as a subcombination or variation of a subcombination.

Moreover, while operations may be depicted in the drawings or described in the specification in a particular order, such operations need not be performed in the particular order shown or in sequential order, or that all operations be performed, to achieve desirable results. Other operations that are not depicted or described can be incorporated in the example methods and processes. For example, one or more additional operations can be performed before, after, simultaneously, or between any of the described operations. Further, the operations may be rearranged or reordered in other implementations. Those skilled in the art will appreciate that in some embodiments, the actual steps taken in the processes illustrated and/or disclosed may differ from those shown in the figures. Depending on the embodiment, certain of the steps described above may be removed, others may be added. Furthermore, the features and attributes of the specific embodiments disclosed above may be combined in different ways to form additional embodiments, all of which fall within the scope of the present disclosure. Also, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described components and systems can generally be integrated together in a single product or packaged into multiple products.

For purposes of this disclosure, certain aspects, advantages, and novel features are described herein. Not necessarily all such advantages may be achieved in accordance with any particular embodiment. Thus, for example, those skilled in the art will recognize that the disclosure may be embodied or carried out in a manner that achieves one advantage or a group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein.

Conditional language, such as “can,” “could,” “might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements, and/or steps. Thus, such conditional language is not generally intended to imply that features, elements, and/or steps are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without user input or prompting, whether these features, elements, and/or steps are included or are to be performed in any particular embodiment.

Conjunctive language such as the phrase “at least one of X, Y, and Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to convey that an item, term, etc. may be either X, Y, or Z. Thus, such conjunctive language is not generally intended to imply that certain embodiments require the presence of at least one of X, at least one of Y, and at least one of Z.

Language of degree used herein, such as the terms “approximately,” “about,” “generally,” and “substantially” as used herein represent a value, amount, or characteristic close to the stated value, amount, or characteristic that still performs a desired function or achieves a desired result. For example, the terms “approximately”, “about”, “generally,” and “substantially” may refer to an amount that is within less than 10% of, within less than 5% of, within less than 1% of, within less than 0.1% of, and within less than 0.01% of the stated amount. As another example, in certain embodiments, the terms “generally parallel” and “substantially parallel” refer to a value, amount, or characteristic that departs from exactly parallel by less than or equal to 15 degrees, 10 degrees, 5 degrees, 3 degrees, 1 degree, or 0.1 degree.

The scope of the present disclosure is not intended to be limited by the specific disclosures of preferred embodiments in this section or elsewhere in this specification, and may be defined by claims as presented in this section or elsewhere in this specification or as presented in the future. The language of the claims is to be interpreted broadly based on the language employed in the claims and not limited to the examples described in the present specification or during the prosecution of the application, which examples are to be construed as non-exclusive.

Of course, the foregoing description is that of certain features, aspects and advantages of the present invention, to which various changes and modifications can be made without departing from the spirit and scope of the present invention. Moreover, the devices described herein need not feature all of the objects, advantages, features and aspects discussed above. Thus, for example, those of skill in the art will recognize that the invention can be embodied or carried out in a manner that achieves or optimizes one advantage or a group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein. In addition, while a number of variations of the invention have been shown and described in detail, other modifications and methods of use, which are within the scope of this invention, will be readily apparent to those of skill in the art based upon this disclosure. It is contemplated that various combinations or subcombinations of these specific features and aspects of embodiments may be made and still fall within the scope of the invention. Accordingly, it should be understood that various features and aspects of the disclosed embodiments can be combined with or substituted for one another in order to form varying modes of the discussed devices.