The invention provides a planarization method, which can make the local flatness of the product to be processed more uniform. The product has a cavity filled with oxide and includes a first electrode layer, a piezoelectric layer and a second electrode layer superposed on the cavity. The first electrode layer covers the cavity and includes a first inclined face around the first electrode layer, and the piezoelectric layer covers the first electrode layer and is arranged on the first electrode layer. The planarization method includes: depositing a passivation layer on the second electrode layer and etching the passivation layer completely until the thickness of the passivation layer is reduced to the required thickness.

A method for manufacturing a vibration element includes, a base film forming step of forming a first base film at a first substrate surface of a quartz crystal substrate in first and second vibrating arm forming regions, a protective film forming step of forming a first protective film in a bank portion forming region of the first base film, and a dry-etching step of dry-etching the quartz crystal substrate through the first base film and the first protective film.

A method for manufacturing a vibration element includes, a base film forming step of forming a first base film at a first substrate surface of a quartz crystal substrate in first and second vibrating arm forming regions, a protective film forming step of forming a first protective film in a bank portion forming region of the first base film, and a dry-etching step of dry-etching the quartz crystal substrate through the first base film and the first protective film.

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.

A bulk-acoustic resonator module includes: a module substrate; a bulk-acoustic resonator connected to the module substrate by a connection terminal and disposed spaced apart from the module substrate; and a sealing portion sealing the bulk-acoustic resonator. The bulk-acoustic resonator includes a resonating portion disposed opposite to an upper surface of the module substrate. A space is disposed between the resonating portion and the upper surface of the module substrate.

The MEMS actuator is formed by a substrate, which surrounds a cavity; by a deformable structure suspended on the cavity; by an actuation structure formed by a first piezoelectric region of a first piezoelectric material, supported by the deformable structure and configured to cause a deformation of the deformable structure; and by a detection structure formed by a second piezoelectric region of a second piezoelectric material, supported by the deformable structure and configured to detect the deformation of the deformable structure.

A method of manufacture and resulting structure for a single crystal electronic device with an enhanced strain interface region. The method of manufacture can include forming a nucleation layer overlying a substrate and forming a first and second single crystal layer overlying the nucleation layer. These first and second layers can be doped by introducing one or more impurity species to form the strained single crystal layers. The first and second strained layers can be aligned along the same crystallographic direction to form a strained single crystal bi-layer having an enhanced strain interface region. Using this enhanced single crystal bi-layer to form active or passive devices results in improved physical characteristics, such as enhanced photon velocity or improved density charges.

The present invention discloses an SOC PMUT suitable for high-density system integration, an array chip and a manufacturing method thereof. With the SOC PMUT suitable for high-density system integration, vertical stacking and monolithic integration of a SOC PMUT array with CMOS auxiliary circuits is realized by means of direct bonding of active wafers and a vertical multi-channel metal wiring structure; in addition, the extension to the package layer is implemented by means of TSVs, without any bonding mini-pad on the periphery of the array for communication with the CMOS. Thus, the bottleneck of metal interconnections in conventional ultrasonic transducers is overcome, the chip area occupied by metal interconnections in ultrasonic transducers is greatly reduced, the metal wiring length is reduced, thus the resulting adverse effects of an electrical parasitic effect on the performance of the ultrasonic transducer array are reduced.

A crystal oscillator includes an oscillating substrate, a hollow frame, a first electrode, and a second electrode. The oscillating substrate includes a main oscillating region and a thinned region that has a thickness smaller than that of the main oscillating region. The first and second electrodes are disposed on a first surface of the oscillating substrate and a second surface opposite to the first surface, respectively. The hollow frame is disposed on the second surface. The second electrode includes a second electrode portion that has at least one opening in positional correspondence with the thinned region. A method for making the crystal oscillator is also provided herein.

A crystal oscillator includes an oscillating substrate, a hollow frame, a first electrode, and a second electrode. The oscillating substrate includes a main oscillating region and a thinned region that has a thickness smaller than that of the main oscillating region. The first and second electrodes are disposed on a first surface of the oscillating substrate and a second surface opposite to the first surface, respectively. The hollow frame is disposed on the second surface. The second electrode includes a second electrode portion that has at least one opening in positional correspondence with the thinned region. A method for making the crystal oscillator is also provided herein.