Described herein is a method of bonding a piezoelectric substrate to a support substrate to form a composite substrate. The piezoelectric substrate has one surface which is positively polarized, and a second surface which is negatively polarized. The method described herein includes the steps of bonding the positively polarized surface of the piezoelectric substrate to one surface of the support substrate by a direct bonding method.

Described herein is a method of bonding a piezoelectric substrate to a support substrate to form a composite substrate. The piezoelectric substrate has one surface which is positively polarized, and a second surface which is negatively polarized. The method described herein includes the steps of bonding the positively polarized surface of the piezoelectric substrate to one surface of the support substrate by a direct bonding method.

A composite substrate 10 includes a semiconductor substrate 12 and an insulating support substrate 14 that are laminated together. The support substrate 14 includes first and second substrates 14a and 14b made of the same material and bonded together with a strength that allows the first and second substrates 14a and 14b to be separated from each other with a blade. The semiconductor substrate 12 is laminated on a surface of the first substrate 14a opposite a surface thereof bonded to the second substrate 14b.

A composite substrate 10 includes a semiconductor substrate 12 and an insulating support substrate 14 that are laminated together. The support substrate 14 includes first and second substrates 14a and 14b made of the same material and bonded together with a strength that allows the first and second substrates 14a and 14b to be separated from each other with a blade. The semiconductor substrate 12 is laminated on a surface of the first substrate 14a opposite a surface thereof bonded to the second substrate 14b.

A surface acoustic wave (SAW) device includes a first interdigital transducer (IDT) and a second IDT each including interdigital electrodes disposed on a first surface of a substrate of piezoelectric material. The SAW device includes a diamond bridge enclosing an air cavity over a wave propagation region on the first surface of the substrate. The diamond bridge has a reduced height and provides improved thermal conductivity to avoid a reduction in performance and/or life span caused by heat generated in the SAW device. A process of fabricating a SAW device includes forming the first IDT and the second IDT in a metal layer on a first surface of a substrate comprising a piezoelectric material, the first IDT and the second IDT disposed in a wave propagation region of the first surface of the substrate, and forming a diamond bridge disposed above the wave propagation region.

Guided Surface Acoustic Wave (SAW) devices with improved quartz orientations are disclosed. A guided SAW device includes a quartz carrier substrate, a piezoelectric layer on a surface of the quartz carrier substrate, and at least one interdigitated transducer on a surface of the piezoelectric layer opposite the quartz carrier substrate. The quartz carrier substrate includes an orientation that provides improved performance parameters for the SAW device, including electromechanical coupling factor, resonator quality factor, temperature coefficient of frequency, and delta temperature coefficient of frequency.

Guided Surface Acoustic Wave (SAW) devices with improved quartz orientations are disclosed. A guided SAW device includes a quartz carrier substrate, a piezoelectric layer on a surface of the quartz carrier substrate, and at least one interdigitated transducer on a surface of the piezoelectric layer opposite the quartz carrier substrate. The quartz carrier substrate includes an orientation that provides improved performance parameters for the SAW device, including electromechanical coupling factor, resonator quality factor, temperature coefficient of frequency, and delta temperature coefficient of frequency.

Aspects of this disclosure relate to an acoustic wave device with transverse mode suppression. The acoustic wave device can include a piezoelectric layer, an interdigital transducer electrode, a temperature compensation layer, and a mass loading strip. The mass loading strip can overlap edge portions of fingers of the interdigital transducer electrode. The mass loading strip can have a sidewall that is tapered inwardly from a bottom side of the mass loading strip to a top side of the mass loading strip. The top side can be shorter than the bottom side.

Aspects of this disclosure relate to an acoustic wave device with transverse mode suppression. The acoustic wave device can include a piezoelectric layer, an interdigital transducer electrode, a temperature compensation layer, and a mass loading strip. The mass loading strip can overlap edge portions of fingers of the interdigital transducer electrode. The mass loading strip can have a sidewall that is tapered inwardly from a bottom side of the mass loading strip to a top side of the mass loading strip. The top side can be shorter than the bottom side.

The present invention relates to a heterostructure, in particular, a piezoelectric structure, comprising a cover layer, in particular, a layer of piezoelectric material, the material of the cover layer having a first coefficient of thermal expansion, assembled to a support substrate, the support substrate having a second coefficient of thermal expansion substantially different from the first coefficient of thermal expansion, at an interface wherein the cover layer comprises at least a recess extending from the interface into the cover layer, and its method of fabrication.