Methods and techniques for fabricating layered structures, such as capacitive micromachined ultrasound transducers, as well as the structures themselves. The layered structure has a membrane that includes a polymer-based layer and a top electrode on the polymer-based layer. The membrane is suspended over a closed cavity and may be actuated by applying a voltage between the top electrode and a bottom electrode that may be positioned along or be a bottom of the closed cavity. The layered structure may be fabricated using a wafer bonding process.

In one embodiment, an RF impedance matching circuit is disclosed. The matching circuit is coupled between a plasma chamber and an RF source providing an RF signal having a frequency. The matching circuit includes a first electronically variable capacitor having a first variable capacitance and a second electronically variable capacitor having a second variable capacitance. A control circuit determines a first parameter related to the plasma chamber, and then determines, based on the first parameter, a first capacitance value for the first electronically variable capacitor and a second capacitance value for the second electronically variable capacitor. The control circuit then generates a control signal to alter the first variable capacitance and the second variable capacitance accordingly, causing the RF power reflected back to the RF source to decrease while the frequency of the RF source is not altered.

In one embodiment, an RF impedance matching circuit is disclosed. The matching circuit is coupled between a plasma chamber and an RF source providing an RF signal having a frequency. The matching circuit includes a first electronically variable capacitor having a first variable capacitance and a second electronically variable capacitor having a second variable capacitance. A control circuit determines a first parameter related to the plasma chamber, and then determines, based on the first parameter, a first capacitance value for the first electronically variable capacitor and a second capacitance value for the second electronically variable capacitor. The control circuit then generates a control signal to alter the first variable capacitance and the second variable capacitance accordingly, causing the RF power reflected back to the RF source to decrease while the frequency of the RF source is not altered.

Methods and techniques for fabricating layered structures using surface micromachining are described. A sacrificial layer is deposited on a substrate assembly that functions as a bottom electrode. The sacrificial layer is patterned into a first shape. A first polymer-based layer is deposited on the sacrificial layer. A top electrode is patterned on the first polymer-based layer above the sacrificial layer. A second polymer-based layer is deposited on the top electrode such that the top electrode is between the first and second polymer-based layers. The sacrificial layer is etched away to form a cavity under the top electrode.

Systems, devices, and methods for adjusting tuning settings of tunable components, such as tunable capacitors, can be configured for calibrating a tunable component. Specifically, the systems, devices and methods can measure a device response for one or more inputs to a tunable component, store a calibration code in a non-volatile memory that characterizes the device response of the tunable component, and adjust a tuning setting of the tunable component based on the calibration code to achieve a desired response of the tunable component.

Systems, devices, and methods for adjusting tuning settings of tunable components, such as tunable capacitors, can be configured for calibrating a tunable component. Specifically, the systems, devices and methods can measure a device response for one or more inputs to a tunable component, store a calibration code in a non-volatile memory that characterizes the device response of the tunable component, and adjust a tuning setting of the tunable component based on the calibration code to achieve a desired response of the tunable component.

An electronic device is provided. The electronic device includes a first conductive layer, a second conductive layer that is formed to be opposite to the first conductive layer. The second conductive layer includes conductors that are electrically separated, and one or more photo-conductive members connected between the conductors. The electronic device further includes an insulating layer that is interposed between the first conductive layer and the second conductive layer, one or more light sources positioned to face the one or more photo-conductive members, and a control circuit. The control circuit outputs a specified light through the light source such that an electric conductivity of the photo-conductive member increases in response to a light, from among the photo-conductive members and some conductors are electrically connected with the photo-conductive member, and a capacitance value between the first conductive layer and the second conductive layer is changed.

An electronic device is provided. The electronic device includes a first conductive layer, a second conductive layer that is formed to be opposite to the first conductive layer. The second conductive layer includes conductors that are electrically separated, and one or more photo-conductive members connected between the conductors. The electronic device further includes an insulating layer that is interposed between the first conductive layer and the second conductive layer, one or more light sources positioned to face the one or more photo-conductive members, and a control circuit. The control circuit outputs a specified light through the light source such that an electric conductivity of the photo-conductive member increases in response to a light, from among the photo-conductive members and some conductors are electrically connected with the photo-conductive member, and a capacitance value between the first conductive layer and the second conductive layer is changed.

A method for manufacturing a multilayer ceramic capacitor includes preparing a green multilayer body including a stack of dielectric sheets printed with inner electrodes, coating the green multilayer body with a conductive paste that is connected to the inner electrodes, and firing the conductive paste and the green multilayer body at the same time, wherein a rate of temperature increase from about 800 C. to about 1,100 C. during the firing is about 15 C. per minute or more.

A method and apparatus for use in a digitally tuning a capacitor in an integrated circuit device is described. A Digitally Tuned Capacitor DTC is described which facilitates digitally controlling capacitance applied between a first and second terminal. In some embodiments, the first terminal comprises an RF+ terminal and the second terminal comprises an RF terminal. In accordance with some embodiments, the DTCs comprise a plurality of sub-circuits ordered in significance from least significant bit (LSB) to most significant bit (MSB) sub-circuits, wherein the plurality of significant bit sub-circuits are coupled together in parallel, and wherein each sub-circuit has a first node coupled to the first RF terminal, and a second node coupled to the second RF terminal. The DTCs further include an input means for receiving a digital control word, wherein the digital control word comprises bits that are similarly ordered in significance from an LSB to an MSB.