Atom A basic unit
of matter. It is the smallest particle of an element that still has the
characteristics of that element. Every atom has a positively charged central
nucleus, surround by a number of negatively charged electrons.
band gap: the energy separation between the top of the valence band and the bottom of the conduction band.
bias: voltage applied to the electrodes in an electrical device, considering polarity.
a voltage, often done to alter the electrical and optical output of a device
such as a light emitting diode
The voltage at which an insulator or dielectric ruptures, or at which ionization
and conduction take place in a gas or vapor.
Capacitance That property of a system of conductors and dielectrics that permits the storage of electricity when potential difference exists between the conductors. Its value is expressed as the ratio of quantity of electricity to a potential difference. A capacitance value is always positive.
conduction band: the
unfilled energy levels into which electrons can be excited to become conductive
electrons; a band that
when partially occupied by mobile electrons, permits their net movement in a particular direction, producing the flow of
electricity through the solid.
conductor: a material with a high electrical conductivity such as copper or aluminum.
Coaxial Cable A high-band
width cable consisting of two concentric cylindrical conductors with a
common axis that is used for high-speed data communication and video signals.
Charge Exchange The loss of an electron by an atomic particle to an ionized atom. This can occur when neutral interstellar material leaks into the heliosphere and runs into ionized solar wind to create pick-up ions.
Dopant An element
incorporated in trace amounts into single crystal silicon or epitaxial
layers to establish their conductivity type and resistivity
and create n-type or p-type silicon. Dopants are
classifed as either acceptors or donors.
Electric Charge A physical state based on the amount and location of electrons and protons in matter. Matter with more electrons than protons is negatively charged. Matter that attracts free electrons is positively charged.
Electron The negatively charged part of an atom. It orbits the atom's nucleus. Electrons are very light compared to protons and neutrons.
Electron volt (eV) The unit used to describe the total energy carried by a particle. It is the energy gained by an electron (or proton, same size of electric charge) moving through a voltage difference of one volt. A keV (or kilo-electron volt) is equal to one thousand electron volts. An MeV (mega-electron volt) is equal to one million electron volts. A GeV (giga-electron volt) is equal to one billion (109) electron volts
Electromagnets When a piece of iron is placed inside a current carrying coil of wire, the iron becomes magnetized and thus increases the magnetic field intensity.
Element A material
consisting of atoms, all with the same atomic number. Approximately 90
different elements are known to exist in nature and several others have
been created in nuclear reactions.
Faraday cup The direct measurement of ion currents collected by a shielded electrode.
Ion An atom that carries a positive or negative electric charge as a result of having lost or gained one or more electrons.
Ionization The process of adding to or removing from an electrically neutral atom or molecule one or more of its electrons.
Ion Beam Neutralization Aelectric charge of opposite polarity to that of the charged beam is generated near the wafer surface to neutralize the charged beam or buildup of electrostatic charge on the wafer surface.
Ion Implantation The ion beam implanter is used to alter the near surface properties of semiconductor materials.
Ion Source An assembly that expelles Positive ions from a discharge by a negatively biased Extraction electrode.
More on Ion Sources...
Isotope Atoms that have the same number of protons but a different number of neutrons. They are atoms of the same element that have different masses. The isotope number is the number of protons plus the number of neutrons.
Impedance The total opposition that a circuit offers to the flow of alternating current or any other varying current at a particular frequency.
Magnetic field A region of space near a magnetized body or electrical current where magnetic forces can be detected.
Magnetic field lines These lines are a way to show the structure of a magnetic field. A compass needle will always point along a field line. The lines are close together where the magnetic force is strong, and spread out where it is weak.
Magnetism (Electromagnetism) A physical property of an object that shows attraction for iron, as in a magnet. Electromagnetism acts between particles with an electric charge, such as electrons, protons, and ions. It is believed to be associated with moving electricity, and it creates fields of force.
Mass The total amount of matter in a body. Mass remains the same even with changes in gravity.
Mass Flow Control (MFC).
The MFC contains a flow sensor and a closed loop servo that adjusts a simple
solenoid valve for the desired flow sensor reading.
Multiple Charged Ions Ions that have lost two or more electrons.
Plasma A fourth state of matter -- not a solid, liquid or gas. In a plasma, the electrons are pulled free from the atoms and can move independently. The individual atoms are charged, even though the total number of positive and negative charges is equal, maintaining an overall electrical neutrality.
Process Chamber The target end of the beamline that includes the wafer handling system, load locks, and a dose monitoring system.
Semiconductor A material, like silicon, whose properties lie in between that of a conductor and an insulator. By doping with impurities, it can be made slightly conductive (n-type) or slightly insulative (p-type).
Space Charge Neutralization
A mechanism by which the space charge effect is reduced in an ion implanter
is the creation of a beam plasma, comprised of positively charged, negatively
charged, and neutral particles
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