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Ion Beam Deposition
Ion beam deposition (IBD) is a process of applying materials to a target through the application of an ion beam. Ion beam deposition setup with mass separator An ion beam deposition apparatus typically consists of an ion source, ion optics, and the deposition target. Optionally a mass analyzer can be incorporated. In the ion source source materials in the form of a gas, an evaporated solid, or a solution (liquid) are ionized. For atomic IBD, electron ionization, field ionization (Penning ion source) or cathodic arc sources are employed. Cathodic arc sources are used particularly for carbon ion deposition. Molecular ion beam deposition employs electrospray ionization or MALDI sources. The ions are then accelerated, focused or deflected using high voltages or magnetic fields. Optional deceleration at the substrate can be employed to define the deposition energy. This energy usually ranges from a few eV up to a few keV. At low energy molecular ion beams are deposited intact (ion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ion Beam
An ion beam is a beam of ions, a type of charged particle beam. Ion beams have many uses in electronics manufacturing (principally ion implantation) and other industries. There are many ion beam sources, some derived from the mercury vapor thrusters developed by NASA in the 1960s. The most widely used ion beams are of singly-charged ions. Units Ion current density is typically measured in mA/cm2, and ion energy in electronvolts (eV). The use of eV is convenient for converting between voltage and energy, especially when dealing with singly charged ion beams. Broad-beam ion sources Most commercial applications use two popular types of ion source, gridded and gridless, which differ in current and power characteristics and the ability to control ion trajectories. In both cases electrons are needed to generate an ion beam. The most common types of electron emitter are hot filament and hollow cathode. Gridded ion source In a gridded ion source, DC or RF discharge are u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ion Implanter Schematic
An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convention. The net charge of an ion is not zero because its total number of electrons is unequal to its total number of protons. A cation is a positively charged ion with fewer electrons than protons (e.g. K+ (potassium ion)) while an anion is a negatively charged ion with more electrons than protons (e.g. Cl− (chloride ion) and OH− (hydroxide ion)). Opposite electric charges are pulled towards one another by electrostatic force, so cations and anions attract each other and readily form ionic compounds. Ions consisting of only a single atom are termed ''monatomic ions'', ''atomic ions'' or ''simple ions'', while ions consisting of two or more atoms are termed polyatomic ions or ''molecular ions''. If only a + or − is present, it indicates ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ion Source
An ion source is a device that creates atomic and molecular ions. Ion sources are used to form ions for mass spectrometers, optical emission spectrometers, particle accelerators, ion implanters and ion engines. Electron ionization Electron ionization is widely used in mass spectrometry, particularly for organic molecules. The gas phase reaction producing electron ionization is :M + e^- -> M^ + 2e^- where M is the atom or molecule being ionized, e^- is the electron, and M^ is the resulting ion. The electrons may be created by an arc discharge between a cathode and an anode. An electron beam ion source (EBIS) is used in atomic physics to produce highly charged ions by bombarding atoms with a powerful electron beam. Its principle of operation is shared by the electron beam ion trap. Electron capture ionization Electron capture ionization (ECI) is the ionization of a gas phase atom or molecule by attachment of an electron to create an ion of the form A−•. The r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electron Ionization
Electron ionization (EI, formerly known as electron impact ionization and electron bombardment ionization) is an ionization method in which energetic electrons interact with solid or gas phase atoms or molecules to produce ions. EI was one of the first ionization techniques developed for mass spectrometry. However, this method is still a popular ionization technique. This technique is considered a hard (high fragmentation) ionization method, since it uses highly energetic electrons to produce ions. This leads to extensive fragmentation, which can be helpful for structure determination of unknown compounds. EI is the most useful for organic compounds which have a Molecular mass, molecular weight below 600 amu. Also, several other thermally stable and Volatility (chemistry), volatile compounds in solid, liquid and gas states can be detected with the use of this technique when coupled with various separation methods. History Electron ionization was first described in 1918 by Can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cathodic Arc
{{Short description, Type of physical vapor deposition technique Cathodic arc deposition or Arc-PVD is a physical vapor deposition technique in which an electric arc is used to vaporize material from a cathode target. The vaporized material then condenses on a substrate, forming a thin film. The technique can be used to deposit metallic, ceramic, and composite films. History Industrial use of modern cathodic arc deposition technology originated in Soviet Union around 1960–1970. By the late 1970s, Soviet government released the use of this technology to the West. Among many designs in USSR at that time the design by L. P. Sablev et al., was allowed to be used outside the USSR. Process The arc evaporation process begins with the striking of a high current, low voltage arc on the surface of a cathode (known as the target) that gives rise to a small (usually a few micrometres wide), highly energetic emitting area known as a cathode spot. The localised temperature at the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon
Carbon () is a chemical element; it has chemical symbol, symbol C and atomic number 6. It is nonmetallic and tetravalence, tetravalent—meaning that its atoms are able to form up to four covalent bonds due to its valence shell exhibiting 4 electrons. It belongs to group 14 of the periodic table. Carbon makes up about 0.025 percent of Earth's crust. Three Isotopes of carbon, isotopes occur naturally, carbon-12, C and carbon-13, C being stable, while carbon-14, C is a radionuclide, decaying with a half-life of 5,700 years. Carbon is one of the timeline of chemical element discoveries#Pre-modern and early modern discoveries, few elements known since antiquity. Carbon is the 15th abundance of elements in Earth's crust, most abundant element in the Earth's crust, and the abundance of the chemical elements, fourth most abundant element in the universe by mass after hydrogen, helium, and oxygen. Carbon's abundance, its unique diversity of organic compounds, and its unusual abi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrospray Ionization
Electrospray ionization (ESI) is a technique used in mass spectrometry to produce ions using an electrospray in which a high voltage is applied to a liquid to create an aerosol. It is especially useful in producing ions from macromolecules because it overcomes the propensity of these molecules to fragment when ionized. ESI is different from other ionization processes (e.g. matrix-assisted laser desorption/ionization, MALDI) since it may produce multiple-charged ions, effectively extending the mass range of the analyser to accommodate the kDa-MDa orders of magnitude observed in proteins and their associated polypeptide fragments. Mass spectrometry using ESI is called electrospray ionization mass spectrometry (ESI-MS) or, less commonly, electrospray mass spectrometry (ES-MS). ESI is a so-called 'soft ionization' technique, since there is very little fragmentation. This can be advantageous in the sense that the molecular ion (or more accurately a pseudo molecular ion) is almost alw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MALDI
In mass spectrometry, matrix-assisted laser desorption/ionization (MALDI) is an ionization technique that uses a laser energy-absorbing matrix to create ions from large molecules with minimal fragmentation. It has been applied to the analysis of biomolecules (biopolymers such as DNA, proteins, peptides and carbohydrates) and various organic molecules (such as polymers, dendrimers and other macromolecules), which tend to be fragile and fragment when ionized by more conventional ionization methods. It is similar in character to electrospray ionization (ESI) in that both techniques are relatively soft (low fragmentation) ways of obtaining ions of large molecules in the gas phase, though MALDI typically produces far fewer multi-charged ions . MALDI methodology is a three-step process. First, the sample is mixed with a suitable matrix material and applied to a metal plate. Second, a pulsed laser irradiates the sample, triggering ablation and desorption of the sample and matrix materi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electronvolt
In physics, an electronvolt (symbol eV), also written electron-volt and electron volt, is the measure of an amount of kinetic energy gained by a single electron accelerating through an Voltage, electric potential difference of one volt in vacuum. When used as a Units of energy, unit of energy, the numerical value of 1 eV in joules (symbol J) is equal to the numerical value of the Electric charge, charge of an electron in coulombs (symbol C). Under the 2019 revision of the SI, this sets 1 eV equal to the exact value Historically, the electronvolt was devised as a standard unit of measure through its usefulness in Particle accelerator#Electrostatic particle accelerators, electrostatic particle accelerator sciences, because a particle with electric charge ''q'' gains an energy after passing through a voltage of ''V''. Definition and use An electronvolt is the amount of energy gained or lost by a single electron when it moves through an Voltage, electric potential differenc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ion Implantation
Ion implantation is a low-temperature process by which ions of one element are accelerated into a solid target, thereby changing the target's physical, chemical, or electrical properties. Ion implantation is used in semiconductor device fabrication and in metal finishing, as well as in materials science research. The ions can alter the elemental composition of the target (if the ions differ in composition from the target) if they stop and remain in the target. Ion implantation also causes chemical and physical changes when the ions impinge on the target at high energy. The crystal structure of the target can be damaged or even destroyed by the energetic collision cascades, and ions of sufficiently high energy (tens of MeV) can cause nuclear transmutation. General principle Ion implantation equipment typically consists of an ion source, where ions of the desired element are produced, an accelerator, where the ions are electrostatically accelerated to a high energy or usin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mass Spectrometer
Mass spectrometry (MS) is an analytical technique that is used to measure the mass-to-charge ratio of ions. The results are presented as a '' mass spectrum'', a plot of intensity as a function of the mass-to-charge ratio. Mass spectrometry is used in many different fields and is applied to pure samples as well as complex mixtures. A mass spectrum is a type of plot of the ion signal as a function of the mass-to-charge ratio. These spectra are used to determine the elemental or isotopic signature of a sample, the masses of particles and of molecules, and to elucidate the chemical identity or structure of molecules and other chemical compounds. In a typical MS procedure, a sample, which may be solid, liquid, or gaseous, is ionized, for example by bombarding it with a beam of electrons. This may cause some of the sample's molecules to break up into positively charged fragments or simply become positively charged without fragmenting. These ions (fragments) are then separated accor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stoichiometry
Stoichiometry () is the relationships between the masses of reactants and Product (chemistry), products before, during, and following chemical reactions. Stoichiometry is based on the law of conservation of mass; the total mass of reactants must equal the total mass of products, so the relationship between reactants and products must form a ratio of positive integers. This means that if the amounts of the separate reactants are known, then the amount of the product can be calculated. Conversely, if one reactant has a known quantity and the quantity of the products can be empirically determined, then the amount of the other reactants can also be calculated. This is illustrated in the image here, where the unbalanced equation is: : : However, the current equation is imbalanced. The reactants have 4 hydrogen and 2 oxygen atoms, while the product has 2 hydrogen and 3 oxygen. To balance the hydrogen, a coefficient of 2 is added to the product H2O, and to fix the imbalance of oxygen, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
