The present disclosure relates to semiconductor structures and, more particularly, to a back-gate controlled varactor and methods of use and manufacture. The varactor includes: a plurality of transistors arranged in parallel; a voltage controlled node coupled to back-gates of the plurality of transistors; and a biasing voltage node coupled to the source and drain of the plurality of transistors.

In one embodiment, a variable capacitance apparatus is disclosed. The variable capacitance apparatus includes a support structure and a plurality of capacitor units. The support structure has a platform, a plurality of walls extending upward from the platform, and a plurality of channels formed between adjacent ones of the walls. Each of the capacitor units has a capacitor and first and second capacitor leads. The plurality of capacitor units are mounted to the support structure so that the plurality of capacitors are positioned within the plurality of channels. Adjacent ones of the plurality of capacitors are separated from one another by one of the plurality of walls to prevent arcing therebetween.

In one embodiment, a variable capacitance apparatus is disclosed. The variable capacitance apparatus includes a support structure and a plurality of capacitor units. The support structure has a platform, a plurality of walls extending upward from the platform, and a plurality of channels formed between adjacent ones of the walls. Each of the capacitor units has a capacitor and first and second capacitor leads. The plurality of capacitor units are mounted to the support structure so that the plurality of capacitors are positioned within the plurality of channels. Adjacent ones of the plurality of capacitors are separated from one another by one of the plurality of walls to prevent arcing therebetween.

An electrochemical reactor includes an ion ON/OFF surface switch operating as an ionic conductor, which includes a pair of electrodes, an electrolyte aqueous solution present between the pair of electrodes, a water-repellent porous fluororesin membrane disposed such that at least one surface thereof is in contact with the electrolyte aqueous solution and including a plurality of pores communicating with each other and a pressing equipment configured to pressurize the electrolyte aqueous solution. As such, electrolysis, a secondary battery and a capacitor, which uses the water-repellent porous fluororesin membrane as an ion ON/OFF surface switch, can be provided.

An electrochemical reactor includes an ion ON/OFF surface switch operating as an ionic conductor, which includes a pair of electrodes, an electrolyte aqueous solution present between the pair of electrodes, a water-repellent porous fluororesin membrane disposed such that at least one surface thereof is in contact with the electrolyte aqueous solution and including a plurality of pores communicating with each other and a pressing equipment configured to pressurize the electrolyte aqueous solution. As such, electrolysis, a secondary battery and a capacitor, which uses the water-repellent porous fluororesin membrane as an ion ON/OFF surface switch, can be provided.

The present provides a variable capacitance element enabling a further reduction in capacitance variation among variable capacitance elements, and provides a packaged circuit including the variable capacitance element. A variable capacitance element is configured to include an element body unit, a compensation unit, a first external terminal for signals, a second external terminal for signals, external terminals for control, and external terminals for capacitance compensation. The compensation unit has second variable-capacitance capacitor units C9 to C 11, each including a second dielectric layer formed of a ferroelectric material, and is connected to the element body unit, and has a capacitance varying according to a control voltage signal.

The present provides a variable capacitance element enabling a further reduction in capacitance variation among variable capacitance elements, and provides a packaged circuit including the variable capacitance element. A variable capacitance element is configured to include an element body unit, a compensation unit, a first external terminal for signals, a second external terminal for signals, external terminals for control, and external terminals for capacitance compensation. The compensation unit has second variable-capacitance capacitor units C9 to C 11, each including a second dielectric layer formed of a ferroelectric material, and is connected to the element body unit, and has a capacitance varying according to a control voltage signal.

In one embodiment, a semiconductor processing tool includes a plasma chamber and an impedance matching circuit. The matching circuit includes a first electronically variable capacitor having a first variable capacitance, a second electronically variable capacitor having a second variable capacitance, and a control circuit. The control circuit is configured to determine a variable impedance of the plasma chamber, determine a first capacitance value for the first electronically variable capacitor and a second capacitance value for the second electronically variable capacitor, and generate a control signal to alter at least one of the first variable capacitance and the second variable capacitance to the first capacitance value and the second capacitance value, respectively. An elapsed time between determining the variable impedance of the plasma chamber to when RF power reflected back to the RF source decreases is less than about 150 sec.

In one embodiment, a semiconductor processing tool includes a plasma chamber and an impedance matching circuit. The matching circuit includes a first electronically variable capacitor having a first variable capacitance, a second electronically variable capacitor having a second variable capacitance, and a control circuit. The control circuit is configured to determine a variable impedance of the plasma chamber, determine a first capacitance value for the first electronically variable capacitor and a second capacitance value for the second electronically variable capacitor, and generate a control signal to alter at least one of the first variable capacitance and the second variable capacitance to the first capacitance value and the second capacitance value, respectively. An elapsed time between determining the variable impedance of the plasma chamber to when RF power reflected back to the RF source decreases is less than about 150 sec.

Devices and methods for improving voltage handling and/or bi-directionality of stacks of elements when connected between terminals are described. Such devices and method include use of symmetrical compensation capacitances, symmetrical series capacitors, or symmetrical sizing of the elements of the stack.