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Capacitively Coupled Plasma
A capacitively coupled plasma (CCP) is one of the most common types of industrial plasma sources. It essentially consists of two metal electrodes separated by a small distance, placed in a reactor. The gas pressure in the reactor can be lower than atmosphere or it can be atmospheric. Description A typical CCP system is driven by a single radio-frequency (RF) power supply, typically at 13.56 MHz.UK Wireless Telegraphy (Short Range Devices) (Exemption) Regulations 199/ref> One of two electrodes is connected to the power supply, and the other one is ground (electricity), grounded. As this configuration is similar in principle to a capacitor in an electric circuit, the plasma formed in this configuration is called a capacitively coupled plasma. When an electric field is generated between electrodes, atoms are ionized and release electrons. The electrons in the gas are accelerated by the RF field and can ionize the gas directly or indirectly by collisions, producing second ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasma Source
Plasma ()πλάσμα , Henry George Liddell, Robert Scott, ''A Greek English Lexicon'', on Perseus is one of the . It contains a significant portion of charged particles – s and/or s. The presence of these charged particles is what primarily sets plasma apart from the other fundamental states of matter. It is the most abundant form of [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Open-circuit Voltage
Open-circuit voltage (abbreviated as OCV or VOC) is the difference of electrical potential between two terminals of an electronic device when disconnected from any circuit. There is no external load connected. No external electric current flows between the terminals. Alternatively, the open-circuit voltage may be thought of as the voltage that must be applied to a solar cell or a battery to stop the current. It is sometimes given the symbol Voc. In network analysis this voltage is also known as the Thévenin voltage. The open-circuit voltages of batteries and solar cells are often quoted under particular conditions (state-of-charge, illumination, temperature, etc.). The potential difference mentioned for batteries and cells is usually the open-circuit voltage. The value of the open-circuit voltage of a transducer equals its electromotive force (emf), which is the maximum potential difference it can produce when not providing current. Example Consider the circuit: If ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Plasma Physics Articles
This is a list of plasma physics topics. A * Ablation * Abradable coating * Abraham–Lorentz force * Absorption band * Accretion disk * Active galactic nucleus * Adiabatic invariant * ADITYA (tokamak) * Aeronomy * Afterglow plasma * Airglow * Air plasma, Corona treatment, Atmospheric-pressure plasma treatment * Ayaks, Novel "Magneto-plasmo-chemical engine" * Alcator C-Mod * Alfvén wave * Ambipolar diffusion * Aneutronic fusion * Anisothermal plasma * Anisotropy * Antiproton Decelerator * Appleton-Hartree equation * Arcing horns * Arc lamp * Arc suppression * ASDEX Upgrade, Axially Symmetric Divertor EXperiment * Astron (fusion reactor) * Astronomy * Astrophysical plasma * Astrophysical X-ray source * Atmospheric dynamo * Atmospheric escape * Atmospheric pressure discharge * Atmospheric-pressure plasma * Atom * Atomic emission spectroscopy * Atomic physics * Atomic-terrace low-angle shadowing * Auger electron spectroscopy * Aurora (astronomy) B * Babcock Model * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multipactor Effect
The multipactor effect is a phenomenon in radio-frequency (RF) amplifier vacuum tubes and waveguides, where, under certain conditions, secondary electron emission in resonance with an alternating electric field leads to exponential electron multiplication, possibly damaging and even destroying the RF device. Description The multipactor effect occurs when electrons accelerated by radio-frequency (RF) fields are self-sustained in a vacuum (or near vacuum) via an electron avalanche caused by secondary electron emission. The impact of an electron to a surface can, depending on its energy and angle, release one or more secondary electrons into the vacuum. These electrons can then be accelerated by the RF fields and impact with the same or another surface. Should the impact energies, number of electrons released, and timing of the impacts be such that a sustained multiplication of the number of electrons occurs, the phenomenon can grow exponentially and may lead to operational problems ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasma Etching
Plasma etching is a form of plasma processing used to fabricate integrated circuits. It involves a high-speed stream of glow discharge ( plasma) of an appropriate gas mixture being shot (in pulses) at a sample. The plasma source, known as etch species, can be either charged ( ions) or neutral (atoms and radicals). During the process, the plasma generates volatile etch products at room temperature from the chemical reactions between the elements of the material etched and the reactive species generated by the plasma. Eventually the atoms of the shot element embed themselves at or just below the surface of the target, thus modifying the physical properties of the target. Mechanisms Plasma generation A plasma is a high energetic condition in which a lot of processes can occur. These processes happen because of electrons and atoms. To form the plasma electrons have to be accelerated to gain energy. Highly energetic electrons transfer the energy to atoms by collisions. Three different ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inductively Coupled Plasma
An inductively coupled plasma (ICP) or transformer coupled plasma (TCP) is a type of plasma source in which the energy is supplied by electric currents which are produced by electromagnetic induction, that is, by time-varying magnetic fields. Operation There are three types of ICP geometries: planar (Fig. 3 (a)), cylindrical (Fig. 3 (b)), and half-toroidal (Fig. 3 (c)). In planar geometry, the electrode is a length of flat metal wound like a spiral (or coil). In cylindrical geometry, it is like a helical spring. In half-toroidal geometry, it is toroidal solenoid cut along its main diameter to two equal halves. When a time-varying electric current is passed through the coil, it creates a time-varying magnetic field around it, with flux \Phi=\pi r^2 H=\pi r^2 H_0 \cos \omega t, where ''r'' is the distance to the center of coil (and of the quartz tube). According to the Faraday–Lenz's law of induction, this creates azimuthal electromotive force in the rarefied gas: U=-\f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Etching (microfabrication)
Etching is used in microfabrication to chemically remove layers from the surface of a wafer during manufacturing. Etching is a critically important process module, and every wafer undergoes many etching steps before it is complete. For many etch steps, part of the wafer is protected from the etchant by a "masking" material which resists etching. In some cases, the masking material is a photoresist which has been patterned using photolithography. Other situations require a more durable mask, such as silicon nitride. Orientation-Dependent Etching * KOH pellets dissolved in water (self-heating) * Etch Rate > >> ** KOH has a slower etching orientation for the planes ** You cannot use this KOH photoresist as a etching mask, because the oxide attacks too slowly, so this resist will not survive * Photoresist can be used a etching mask, and the best photoresist for etching is nitride * For example, the etch rate of Si in KOH Depends on Crystallographic Plane * At low temperat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasma-enhanced Chemical Vapor Deposition
Plasma-enhanced chemical vapor deposition (PECVD) is a chemical vapor deposition process used to deposit thin films from a gas state (vapor) to a solid state on a substrate. Chemical reactions are involved in the process, which occur after creation of a plasma of the reacting gases. The plasma is generally created by radio frequency (RF) (alternating current (AC)) frequency or direct current (DC) discharge between two electrodes, the space between which is filled with the reacting gases. Discharges for processes A plasma is any gas in which a significant percentage of the atoms or molecules are ionized. Fractional ionization in plasmas used for deposition and related materials processing varies from about 10−4 in typical capacitive discharges to as high as 5–10% in high-density inductive plasmas. Processing plasmas are typically operated at pressures of a few millitorrs to a few torr, although arc discharges and inductive plasmas can be ignited at atmospheric pressure. P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sputtering
In physics, sputtering is a phenomenon in which microscopic particles of a solid material are ejected from its surface, after the material is itself bombarded by energetic particles of a plasma or gas. It occurs naturally in outer space, and can be an unwelcome source of wear in precision components. However, the fact that it can be made to act on extremely fine layers of material is utilised in science and industry—there, it is used to perform precise etching, carry out analytical techniques, and deposit thin film layers in the manufacture of optical coatings, semiconductor devices and nanotechnology products. It is a physical vapor deposition technique. Physics When energetic ions collide with atoms of a target material, an exchange of momentum takes place between them. These ions, known as "incident ions", set off collision cascades in the target. Such cascades can take many paths; some recoil back toward the surface of the target. If a collision cascade reaches the surf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thin Film Deposition
A thin film is a layer of material ranging from fractions of a nanometer (monolayer) to several micrometers in thickness. The controlled synthesis of materials as thin films (a process referred to as deposition) is a fundamental step in many applications. A familiar example is the household mirror, which typically has a thin metal coating on the back of a sheet of glass to form a reflective interface. The process of silvering was once commonly used to produce mirrors, while more recently the metal layer is deposited using techniques such as sputtering. Advances in thin film deposition techniques during the 20th century have enabled a wide range of technological breakthroughs in areas such as magnetic recording media, electronic semiconductor devices, integrated passive devices, LEDs, optical coatings (such as antireflective coatings), hard coatings on cutting tools, and for both energy generation (e.g. thin-film solar cells) and storage ( thin-film batteries). It is also b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reactive-ion Etching
Reactive-ion etching (RIE) is an etching technology used in microfabrication. RIE is a type of dry etching which has different characteristics than wet etching. RIE uses chemically reactive plasma to remove material deposited on wafers. The plasma is generated under low pressure (vacuum) by an electromagnetic field. High-energy ions from the plasma attack the wafer surface and react with it. Equipment A typical (parallel plate) RIE system consists of a cylindrical vacuum chamber, with a wafer platter situated in the bottom portion of the chamber. The wafer platter is electrically isolated from the rest of the chamber. Gas enters through small inlets in the top of the chamber, and exits to the vacuum pump system through the bottom. The types and amount of gas used vary depending upon the etch process; for instance, sulfur hexafluoride is commonly used for etching silicon. Gas pressure is typically maintained in a range between a few millitorr and a few hundred millitorr by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microfabrication
Microfabrication is the process of fabricating miniature structures of micrometre scales and smaller. Historically, the earliest microfabrication processes were used for integrated circuit fabrication, also known as "semiconductor manufacturing" or "semiconductor device fabrication". In the last two decades microelectromechanical systems (MEMS), microsystems (European usage), micromachines (Japanese terminology) and their subfields, microfluidics/lab-on-a-chip, optical MEMS (also called MOEMS), RF MEMS, PowerMEMS, BioMEMS and their extension into nanoscale (for example NEMS, for nano electro mechanical systems) have re-used, adapted or extended microfabrication methods. Flat-panel displays and solar cells are also using similar techniques. Miniaturization of various devices presents challenges in many areas of science and engineering: physics, chemistry, materials science, computer science, ultra-precision engineering, fabrication processes, and equipment design. It is also gi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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