A method for fabricating a semiconductor device involves providing a transistor device, forming one or more electrical connections to the transistor device, forming one or more dielectric layers over at least a portion of the electrical connections, applying an interface material over at least a portion of the one or more dielectric layers, removing at least a portion of the interface material to form a trench, and covering at least a portion of the interface material and the trench with a substrate layer to form a cavity.

A method for fabricating a semiconductor device involves providing a semiconductor substrate, forming an oxide layer in the semiconductor substrate, forming a transistor device over the oxide layer, removing at least part of a backside of the semiconductor substrate, applying a sacrificial material below the oxide layer, covering the sacrificial material with an interface material, and removing at least a portion of the sacrificial material to form a cavity at least partially covered by the interface layer.

A longitudinally coupled resonator-type surface acoustic wave filter includes a low acoustic velocity film and a piezoelectric film stacked over a high acoustic velocity component in which a bulk wave propagates at an acoustic velocity higher than an acoustic velocity of an elastic wave that propagates in the piezoelectric film. IDT electrodes are provided on one surface of the piezoelectric film. The longitudinally coupled resonator-type surface acoustic wave filter uses a SH wave. At least one of the IDT electrodes has a duty factor that is adjusted over an entire length of the one of the IDT electrodes in the direction of elastic wave propagation to suppress a Rayleigh wave spurious response.

A guided surface acoustic wave (SAW) device includes a substrate, a piezoelectric layer on the substrate, and a transducer on the piezoelectric layer. The substrate is silicon, and has a crystalline orientation defined by a first Euler angle (), a second Euler angle (), and a third Euler angle (). The first Euler angle (), the second Euler angle (), and the third Euler angle () are chosen such that a velocity of wave propagation within the substrate is less than 5,400 m/s.

An elastic wave device includes a support substrate made of silicon, a piezoelectric film disposed directly or indirectly on the support substrate, and an interdigital transducer electrode disposed on one surface of the piezoelectric film. A higher-order mode acoustic velocity of propagation through the piezoelectric film is equal or substantially equal to an acoustic velocity V.sub.si=(V.sub.1).sup.1/2 of propagation through silicon or higher than the acoustic velocity V.sub.si, where V.sub.si is specified by V.sub.1 among solutions V.sub.1, V.sub.2, and V.sub.3 with respect to x derived from Ax.sup.3+Bx.sup.2+Cx+D=0.

A guided acoustic wave device includes a substrate, a lithium tantalate layer on the substrate, and a transducer on the lithium tantalate film. The lithium tantalate has a crystalline orientation defined by (YXl), where is between 10 and 37. The inventors discovered that limiting the crystalline orientation of the lithium tantalate in this manner provides significant increases in the electromechanical coupling coefficient of the acoustic wave device, thereby increasing bandwidth and improving performance.

A semiconductor device includes a transistor device implemented over an oxide layer, an interface layer applied below at least a portion of the oxide layer, the interface layer having a trench formed therein, and a substrate layer covering at least a portion of the interface layer and the trench to form a cavity.

A method for fabricating a semiconductor device involves providing a semiconductor substrate, forming an oxide layer in the semiconductor substrate, forming a transistor device over the oxide layer, removing at least part of a backside of the semiconductor substrate, applying a sacrificial material below the oxide layer, covering the sacrificial material with an interface material, and removing at least a portion of the sacrificial material to form a cavity at least partially covered by the interface layer.

A method for fabricating a semiconductor device involves providing a transistor device, forming one or more electrical connections to the transistor device, forming one or more dielectric layers over at least a portion of the electrical connections, applying an interface material over at least a portion of the one or more dielectric layers, removing at least a portion of the interface material to form a trench, and covering at least a portion of the interface material and the trench with a substrate layer to form a cavity.

A surface acoustic wave (SAW) device according to the present invention includes: a substrate; an intermediate layer formed on an upper surface of the substrate; a piezoelectric layer formed on an upper surface of the intermediate layer; and an inter-digital transducer (IDT) electrode formed on an upper surface of the piezoelectric layer to generate a SAW, wherein an upper portion of the substrate is deformed by a predetermined thickness by ion implantation to form an ion trap layer and the intermediate layer is formed on an upper surface of the ion trap layer.