Ion Implantation


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ion implantation

[′ī‚än ‚im‚plan′tā·shən]
(engineering)
A process of introducing impurities into the near-surface regions of solids by directing a beam of ions at the solid.

Ion Implantation

 

(also called ion alloying), the implantation of extrinsic atoms in a solid by bombarding its surface with ions. The greater the energy of the ions, the greater will be the average depth to which ions penetrate into the target (ions with energies of ~ 10–100 kilo electron volts penetrate to a depth of 0.01–1.0 micron). On bombardment of single crystals the depth of penetration of particles in certain crystallographic directions increases sharply.

During intensive bombardment ion implantation is affected by cathode sputtering of the target, the diffusion of the implanted ions, and their explusion from the surface. Maximum possible concentration of implanted ions depends on the type of ion and target and on the temperature of the target.

Ion implantation is used most widely to implant impurities in semiconductor single crystals in order to create the required impurity electrical conductivity of the semiconductor. The subsequent annealing is used to eliminate the crystal defects that form and also to ensure that the implanted ions occupy certain positions at points of the crystal lattice. Ion implantation makes possible the introduction of precisely measured quantities of almost any chemical elements into various semiconductor materials. The distribution of implanted ions with respect to depth may be controlled by modifying the energy of the ions and the intensity and direction of the ion beam with respect to the crystallographic axes. Ion implantation makes it possible to create in a semiconductor crystal a p-n transition at shallow depth, which increases, for example, the maximum frequency of transistors.

REFERENCES

Mayer, J., A. Erikssen, and J. Davies. Ionnoe legirovanie poluprovodnikov (kremnii, germanii).Moscow [in press]. (Translated from English.)
Legirovanie poluprovodnikov ionnym vnedreniem. Moscow, 1971. (Translated from English.)

IU. V. MARTYNENKO

Ion implantation

A process that utilizes accelerated ions to penetrate a solid surface. The implanted ions can be used to modify the surface composition, structure, or property of the solid material. This surface modification depends on the ion species, energy, and flux. The penetration depth can be controlled by adjusting the ion energy and the type of ions used. The total number of ions incorporated into the solid is determined by the ion flux and the duration of implantation. This technique allows for the precise placement of ions in a solid at low temperatures. It is used for many applications such as modifying the electrical properties of semiconductors and improving the mechanical or chemical properties of alloys, metals, and dielectrics. See Alloy, Dielectric materials, Metal, Semiconductor

Wide ranges of ion energy and dose are applied. For ion energy ranging from 1 keV to 10 MeV, the ion penetration depth varies from 10 nanometers to 50 micrometers. In general, it is difficult to get deeper penetration since extremely high energy ions are required. As such, ion implantation is a surface modification technique and not suitable for changing the entire bulk property of a solid. Ion dosage also varies depending on the applications. Doses ranging from 1010 to 1018 ions/cm2 are typically applied. For high-dose applications, ion sources providing high ion currents are needed to keep the implantation time reasonable for production purposes.

Ion implantation is used extensively in the semiconductor industry. The fabrication of integrated circuits in silicon often requires many steps of ion implantation with different ion species and energies. The implanted ions serve as dopants in semiconductors, changing their conductivity by more than a factor of 108. See Integrated circuits

Ion implantation is also used to change the surface properties of metals and alloys. It has been applied successfully to improve wear resistance, fatigue life, corrosion protection, and chemical resistance of different materials. Even though the ion projected range is less than 1 μm, surface treatment by ion implantation can extend the lives of metal or ceramic tools by 80 times or more. Ion implantation can form new compounds such as nitrides on the surface, and the implanted ions can be found at much greater depths than the projected range due to diffusion or mechanical mixing. See Ceramics

References in periodicals archive ?
To avoid these effects it is convenient to obtain the amplification factor ([DELTA][I.sub.em]) of PL near the saturated pump power regime as the quotient between the PL intensity of a sample with metal ion implantation ([I.sub.siNCs-MIons]), and one without it ([I.sub.SiNCs]).
Sielanko, Surface modification of Ti-6Al-4V alloy by nitrogen ion implantation. Wear, 2006.
Ion implantation is a methodology for cutting tools processing, using the atoms of nitrogen and their implanting in crystal structure-grate of the tool material, with out of deposition of hard thin layer.
(1995): "Methane Plasma Source Ion Implantation (PSII) for Improvement of Tribological and Corrosion Properties," J.
There are several other doping techniques that can be used, but they don't have the kind of control that ion implantation has."
Although the ion implantation process is straightforward, carrying it out to maximum advantage involves an understanding of solid state physics as well as the classical metallurgical approach of relating surface structure and properties.
The GaAs MESFET's active channel and the N+ region are formed by selective silicon 28 ion implantation directly into 3" in diameter, (100), semi-insulating GaAs substrates.
Silver Ion Implantation. Silver ion implantation was performed using an ion implantation machine equipped with a metal vapor vacuum arc (MEVVA) ion source.
The opening section on shape memory alloys investigates the internal friction of hydrogenated Ti (Ni,Cu) shape memory alloys, the effect of heat treatments on damping characteristics, and the suppression of martensitic phase transformation by ion implantation. Other topics include the addition of silicon and cobalt to Fe-Mn alloys, hydrogen-induces damping peak temperatures in bulk metallic glasses, ceramic polymer composites for musical instruments, and uses of high damping stainless alloy HIDAS.
Lorentz, from Integrated Engineering Software, is a powerful boundary element method tool for the design and analysis of CRT and x-ray tubes, ion implantation, disk sputtering, electron gun design, mass spectrometers, semiconductors, and more.
of Gloucester, Mass., says its "ion implantation" advance probably would belong to the Japanese today if not for the National Institute of Standards and Technology's Advanced Technology Program, which co-funded the underlying research and development.
Using selective ion implantation and pulsed laser annealing, Stabile et al [1, 2] have developed PIN diodes suitable for applications at mm-wave frequencies.