Sputtering

Last updated
A commercial AJA Orion sputtering system at Cornell NanoScale Science and Technology Facility Sputtering system.jpg
A commercial AJA Orion sputtering system at Cornell NanoScale Science and Technology Facility
Ion thruster operating on iodine (yellow) using a xenon (blue) hollow cathode. High-energy ions emitted from plasma thrusters sputter material off the surrounding test chamber, causing problems for ground testing of high-power thrusters. Busek's BET-3 Ion Thruster.jpg
Ion thruster operating on iodine (yellow) using a xenon (blue) hollow cathode. High-energy ions emitted from plasma thrusters sputter material off the surrounding test chamber, causing problems for ground testing of high-power thrusters.

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. [2] 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. [3]

Contents

Physics

When energetic ions collide with atoms of a target material, an exchange of momentum takes place between them. [2] [4] [5]

Sputtering from a linear collision cascade. The thick line illustrates the position of the surface, with everything below it being atoms inside of the material, and the thinner lines the ballistic movement paths of the atoms from beginning until they stop in the material. The purple circle is the incoming ion. Red, blue, green and yellow circles illustrate primary, secondary, tertiary and quaternary recoils, respectively. Two of the atoms happen to move out from the sample, i.e. they are sputtered. Linearcollisioncascadesput.png
Sputtering from a linear collision cascade. The thick line illustrates the position of the surface, with everything below it being atoms inside of the material, and the thinner lines the ballistic movement paths of the atoms from beginning until they stop in the material. The purple circle is the incoming ion. Red, blue, green and yellow circles illustrate primary, secondary, tertiary and quaternary recoils, respectively. Two of the atoms happen to move out from the sample, i.e. they are sputtered.

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 surface of the target, and its remaining energy is greater than the target's surface binding energy, an atom will be ejected. This process is known as "sputtering". If the target is thin (on an atomic scale), the collision cascade can reach through to its back side; the atoms ejected in this fashion are said to escape the surface binding energy "in transmission".

The average number of atoms ejected from the target per incident ion is called the "sputter yield". The sputter yield depends on several things: the angle at which ions collide with the surface of the material, how much energy they strike it with, their masses, the masses of the target atoms, and the target's surface binding energy. If the target possesses a crystal structure, the orientation of its axes with respect to the surface is an important factor.

The ions that cause sputtering come from a variety of sources—they can come from plasma, specially constructed ion sources, particle accelerators, outer space (e.g. solar wind), or radioactive materials (e.g. alpha radiation).

A model for describing sputtering in the cascade regime for amorphous flat targets is Thompson's analytical model. [6] An algorithm that simulates sputtering based on a quantum mechanical treatment including electrons stripping at high energy is implemented in the program TRIM. [7]

Another mechanism of physical sputtering is called "heat spike sputtering". This can occur when the solid is dense enough, and the incoming ion heavy enough, that collisions occur very close to each other. In this case, the binary collision approximation is no longer valid, and the collisional process should be understood as a many-body process. The dense collisions induce a heat spike (also called thermal spike), which essentially melts a small portion of the crystal. If that portion is close enough to its surface, large numbers of atoms may be ejected, due to liquid flowing to the surface and/or microexplosions. [8] Heat spike sputtering is most important for heavy ions (e.g. Xe or Au or cluster ions) with energies in the keV–MeV range bombarding dense but soft metals with a low melting point (Ag, Au, Pb, etc.). The heat spike sputtering often increases nonlinearly with energy, and can for small cluster ions lead to dramatic sputtering yields per cluster of the order of 10,000. [9] For animations of such a process see "Re: Displacement Cascade 1" in the external links section.

Physical sputtering has a well-defined minimum energy threshold, equal to or larger than the ion energy at which the maximum energy transfer from the ion to a target atom equals the binding energy of a surface atom. That is to say, it can only happen when an ion is capable of transferring more energy into the target than is required for an atom to break free from its surface.

This threshold is typically somewhere in the range of ten to a hundred eV.

Preferential sputtering can occur at the start when a multicomponent solid target is bombarded and there is no solid state diffusion. If the energy transfer is more efficient to one of the target components, or it is less strongly bound to the solid, it will sputter more efficiently than the other. If in an AB alloy the component A is sputtered preferentially, the surface of the solid will, during prolonged bombardment, become enriched in the B component, thereby increasing the probability that B is sputtered such that the composition of the sputtered material will ultimately return to AB.

Electronic sputtering

The term electronic sputtering can mean either sputtering induced by energetic electrons (for example in a transmission electron microscope), or sputtering due to very high-energy or highly charged heavy ions that lose energy to the solid, mostly by electronic stopping power, where the electronic excitations cause sputtering. [10] Electronic sputtering produces high sputtering yields from insulators, as the electronic excitations that cause sputtering are not immediately quenched, as they would be in a conductor. One example of this is Jupiter's ice-covered moon Europa, where a MeV sulfur ion from Jupiter's magnetosphere can eject up to 10,000 H2O molecules. [11]

Potential sputtering

A commercial sputtering system Sputterer.JPG
A commercial sputtering system

In the case of multiple charged projectile ions a particular form of electronic sputtering can take place that has been termed potential sputtering. [12] [13] In these cases the potential energy stored in multiply charged ions (i.e., the energy necessary to produce an ion of this charge state from its neutral atom) is liberated when the ions recombine during impact on a solid surface (formation of hollow atoms). This sputtering process is characterized by a strong dependence of the observed sputtering yields on the charge state of the impinging ion and can already take place at ion impact energies well below the physical sputtering threshold. Potential sputtering has only been observed for certain target species [14] and requires a minimum potential energy. [15]

Etching and chemical sputtering

Removing atoms by sputtering with an inert gas is called ion milling or ion etching.

Sputtering can also play a role in reactive-ion etching (RIE), a plasma process carried out with chemically active ions and radicals, for which the sputtering yield may be enhanced significantly compared to pure physical sputtering. Reactive ions are frequently used in secondary ion mass spectrometry (SIMS) equipment to enhance the sputter rates. The mechanisms causing the sputtering enhancement are not always well understood, although the case of fluorine etching of Si has been modeled well theoretically. [16]

Sputtering observed to occur below the threshold energy of physical sputtering is also often called chemical sputtering. [2] [5] The mechanisms behind such sputtering are not always well understood, and may be hard to distinguish from chemical etching. At elevated temperatures, chemical sputtering of carbon can be understood to be due to the incoming ions weakening bonds in the sample, which then desorb by thermal activation. [17] The hydrogen-induced sputtering of carbon-based materials observed at low temperatures has been explained by H ions entering between C-C bonds and thus breaking them, a mechanism dubbed swift chemical sputtering. [18]

Applications and phenomena

Sputtering only happens when the kinetic energy of the incoming particles is much higher than conventional thermal energies (≫ 1 eV). When done with direct current (DC sputtering), voltages of 3-5 kV are used. When done with alternating current (RF sputtering), frequencies are around the 14 MHz range.

Sputter cleaning

Surfaces of solids can be cleaned from contaminants by using physical sputtering in a vacuum. Sputter cleaning is often used in surface science, vacuum deposition and ion plating. In 1955 Farnsworth, Schlier, George, and Burger reported using sputter cleaning in an ultra-high-vacuum system to prepare ultra-clean surfaces for low-energy electron-diffraction (LEED) studies. [19] [20] [21] Sputter cleaning became an integral part of the ion plating process. When the surfaces to be cleaned are large, a similar technique, plasma cleaning, can be used. Sputter cleaning has some potential problems such as overheating, gas incorporation in the surface region, bombardment (radiation) damage in the surface region, and the roughening of the surface, particularly if over done. It is important to have a clean plasma in order to not continually recontaminate the surface during sputter cleaning. Redeposition of sputtered material on the substrate can also give problems, especially at high sputtering pressures. Sputtering of the surface of a compound or alloy material can result in the surface composition being changed. Often the species with the least mass or the highest vapor pressure is the one preferentially sputtered from the surface.

Film deposition

Sputter deposition is a method of depositing thin films by sputtering that involves eroding material from a "target" source onto a "substrate", e.g. a silicon wafer, solar cell, optical component, or many other possibilities. [22] Resputtering, in contrast, involves re-emission of the deposited material, e.g. SiO2 during the deposition also by ion bombardment.

Sputtered atoms are ejected into the gas phase but are not in their thermodynamic equilibrium state, and tend to deposit on all surfaces in the vacuum chamber. A substrate (such as a wafer) placed in the chamber will be coated with a thin film. Sputtering deposition usually uses an argon plasma because argon, a noble gas, will not react with the target material.

Sputter damage

Sputter damage is usually defined during transparent electrode deposition on optoelectronic devices, which is usually originated from the substrate's bombardment by highly energetic species. The main species involved in the process and the representative energies can be listed as (values taken from [23] ):

As seen in the list above, negative ions (e.g., O− and In− for ITO sputtering) formed at the target surface and accelerated toward the substrate acquire the largest energy, which is determined by the potential between target and plasma potentials. Although the flux of the energetic particles is an important parameter, high-energy negative O− ions are additionally the most abundant species in plasma in case of reactive deposition of oxides. However, energies of other ions/atoms (e.g., Ar+, Ar0, or In0) in the discharge may already be sufficient to dissociate surface bonds or etch soft layers in certain device technologies. In addition, the momentum transfer of high-energy particles from the plasma (Ar, oxygen ions) or sputtered from the target might impinge or even increase the substrate temperature sufficiently to trigger physical (e.g., etching) or thermal degradation of sensitive substrate layers (e.g. thin film metal halide perovskites).

This can affect the functional properties of underlying charge transport and passivation layers and photoactive absorbers or emitters, eroding device performance. For instance, due to sputter damage, there may be inevitable interfacial consequences such as pinning of the Fermi level, caused by damage-related interface gap states, resulting in the formation of Schottky-barrier impeding carrier transport. Sputter damage can also impair the doping efficiency of materials and the lifetime of excess charge carriers in photoactive materials; in some cases, depending on its extent, such damage can even lead to a reduced shunt resistance. [23]

Etching

In the semiconductor industry sputtering is used to etch the target. Sputter etching is chosen in cases where a high degree of etching anisotropy is needed and selectivity is not a concern. One major drawback of this technique is wafer damage and high voltage use.

For analysis

Another application of sputtering is to etch away the target material. One such example occurs in secondary ion mass spectrometry (SIMS), where the target sample is sputtered at a constant rate. As the target is sputtered, the concentration and identity of sputtered atoms are measured using mass spectrometry. In this way the composition of the target material can be determined and even extremely low concentrations (20 μg/kg) of impurities detected. Furthermore, because the sputtering continually etches deeper into the sample, concentration profiles as a function of depth can be measured.

In space

Sputtering is one of the forms of space weathering, a process that changes the physical and chemical properties of airless bodies, such as asteroids and the Moon. On icy moons, especially Europa, sputtering of photolyzed water from the surface leads to net loss of hydrogen and accumulation of oxygen-rich materials that may be important for life. Sputtering is also one of the possible ways that Mars has lost most of its atmosphere and that Mercury continually replenishes its tenuous surface-bounded exosphere.

Optics

Due to its adaptability with a wide range of materials, Sputtering is used to create various types of coatings that enhance the performance of optical components. [24] Anti-reflective coatings are applied to lenses and optical instruments to minimize light reflection and increase light transmission, which improves clarity and reduces glare. [25] Sputtering is also used to deposit reflective coatings on mirrors, ensuring high reflectivity and durability for applications such as telescopes, cameras, and laser systems. [26]

Related Research Articles

<span class="mw-page-title-main">MEMS</span> Very small devices that incorporate moving components

MEMS is the technology of microscopic devices incorporating both electronic and moving parts. MEMS are made up of components between 1 and 100 micrometres in size, and MEMS devices generally range in size from 20 micrometres to a millimetre, although components arranged in arrays can be more than 1000 mm2. They usually consist of a central unit that processes data and several components that interact with the surroundings.

<span class="mw-page-title-main">Ion source</span> Device that creates charged atoms and molecules (ions)

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.

<span class="mw-page-title-main">Pulsed laser deposition</span>

Pulsed laser deposition (PLD) is a physical vapor deposition (PVD) technique where a high-power pulsed laser beam is focused inside a vacuum chamber to strike a target of the material that is to be deposited. This material is vaporized from the target which deposits it as a thin film on a substrate. This process can occur in ultra high vacuum or in the presence of a background gas, such as oxygen which is commonly used when depositing oxides to fully oxygenate the deposited films.

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 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, light-emitting diodes, optical coatings, hard coatings on cutting tools, and for both energy generation and storage. It is also being applied to pharmaceuticals, via thin-film drug delivery. A stack of thin films is called a multilayer.

<span class="mw-page-title-main">Coulomb explosion</span> Injection of EM radiation into a solid, resulting in bond breakage

A Coulombic explosion is a condensed-matter physics process in which a molecule or crystal lattice is destroyed by the Coulombic repulsion between its constituent atoms. Coulombic explosions are a prominent technique in laser-based machining, and appear naturally in certain high-energy reactions.

<span class="mw-page-title-main">Ion plating</span> Method of coating solid surfaces with ions

Ion plating (IP) is a physical vapor deposition (PVD) process that is sometimes called ion assisted deposition (IAD) or ion vapor deposition (IVD) and is a modified version of vacuum deposition. Ion plating uses concurrent or periodic bombardment of the substrate, and deposits film by atomic-sized energetic particles called ions. Bombardment prior to deposition is used to sputter clean the substrate surface. During deposition the bombardment is used to modify and control the properties of the depositing film. It is important that the bombardment be continuous between the cleaning and the deposition portions of the process to maintain an atomically clean interface. If this interface is not properly cleaned, then it can result into a weaker coating or poor adhesion.

<span class="mw-page-title-main">Bismuth telluride</span> Chemical compound

Bismuth telluride is a gray powder that is a compound of bismuth and tellurium also known as bismuth(III) telluride. It is a semiconductor, which, when alloyed with antimony or selenium, is an efficient thermoelectric material for refrigeration or portable power generation. Bi2Te3 is a topological insulator, and thus exhibits thickness-dependent physical properties.

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 at a sample. The plasma source, known as etch species, can be either charged (ions) or neutral. 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.

<span class="mw-page-title-main">Stopping power (particle radiation)</span> Retarding force acting on charged particles due to interactions with matter

In nuclear and materials physics, stopping power is the retarding force acting on charged particles, typically alpha and beta particles, due to interaction with matter, resulting in loss of particle kinetic energy. Stopping power is also interpreted as the rate at which a material absorbs the kinetic energy of a charged particle. Its application is important in a wide range of thermodynamic areas such as radiation protection, ion implantation and nuclear medicine.

Electron-beam physical vapor deposition, or EBPVD, is a form of physical vapor deposition in which a target anode is bombarded with an electron beam given off by a charged tungsten filament under high vacuum. The electron beam causes atoms from the target to transform into the gaseous phase. These atoms then precipitate into solid form, coating everything in the vacuum chamber with a thin layer of the anode material.

<span class="mw-page-title-main">Vacuum deposition</span> Method of coating solid surfaces

Vacuum deposition is a group of processes used to deposit layers of material atom-by-atom or molecule-by-molecule on a solid surface. These processes operate at pressures well below atmospheric pressure. The deposited layers can range from a thickness of one atom up to millimeters, forming freestanding structures. Multiple layers of different materials can be used, for example to form optical coatings. The process can be qualified based on the vapor source; physical vapor deposition uses a liquid or solid source and chemical vapor deposition uses a chemical vapor.

Penning ionization is a form of chemi-ionization, an ionization process involving reactions between neutral atoms or molecules. The Penning effect is put to practical use in applications such as gas-discharge neon lamps and fluorescent lamps, where the lamp is filled with a Penning mixture to improve the electrical characteristics of the lamps.

<span class="mw-page-title-main">Plasma-enhanced chemical vapor deposition</span> Method of depositing thin films onto a substrate

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.

<span class="mw-page-title-main">Sputter deposition</span> Method of thin film application

Sputter deposition is a physical vapor deposition (PVD) method of thin film deposition by the phenomenon of sputtering. This involves ejecting material from a "target" that is a source onto a "substrate" such as a silicon wafer. Resputtering is re-emission of the deposited material during the deposition process by ion or atom bombardment. Sputtered atoms ejected from the target have a wide energy distribution, typically up to tens of eV. The sputtered ions can ballistically fly from the target in straight lines and impact energetically on the substrates or vacuum chamber. Alternatively, at higher gas pressures, the ions collide with the gas atoms that act as a moderator and move diffusively, reaching the substrates or vacuum chamber wall and condensing after undergoing a random walk. The entire range from high-energy ballistic impact to low-energy thermalized motion is accessible by changing the background gas pressure. The sputtering gas is often an inert gas such as argon. For efficient momentum transfer, the atomic weight of the sputtering gas should be close to the atomic weight of the target, so for sputtering light elements neon is preferable, while for heavy elements krypton or xenon are used. Reactive gases can also be used to sputter compounds. The compound can be formed on the target surface, in-flight or on the substrate depending on the process parameters. The availability of many parameters that control sputter deposition make it a complex process, but also allow experts a large degree of control over the growth and microstructure of the film.

High-power impulse magnetron sputtering is a method for physical vapor deposition of thin films which is based on magnetron sputter deposition. HIPIMS utilises extremely high power densities of the order of kW⋅cm−2 in short pulses (impulses) of tens of microseconds at low duty cycle of < 10%. Distinguishing features of HIPIMS are a high degree of ionisation of the sputtered metal and a high rate of molecular gas dissociation which result in high density of deposited films. The ionization and dissociation degree increase according to the peak cathode power. The limit is determined by the transition of the discharge from glow to arc phase. The peak power and the duty cycle are selected so as to maintain an average cathode power similar to conventional sputtering (1–10 W⋅cm−2).

<span class="mw-page-title-main">Hollow atom</span> Type of atom

Hollow atoms are short-lived multiply excited neutral atoms which carry a large part of their Z electrons in high-n levels while inner shells remain (transiently) empty. The hollow atoms are exotic atomic species whose all, or most, electrons lie in excited states, while the innermost shells are empty. These atomic species were first observed during the interaction of highly charged ions with surfaces. population inversion arises for typically 100 femtoseconds during the interaction of a slow highly charged ion (HCI) with a solid surface.
Despite this limited lifetime, the formation and decay of a hollow atom can be conveniently studied from ejected electrons and soft X-rays, and the trajectories, energy loss and final charge state distribution of surface-scattered projectiles. For impact on insulator surfaces the potential energy contained by hollow atom may also cause the release of target atoms and -ions via potential sputtering and the formation of nanostructures on a surface.

<span class="mw-page-title-main">Collision cascade</span> Series of collisions between nearby atoms, initiated by a single energetic atom

In condensed-matter physics, a collision cascade is a set of nearby adjacent energetic collisions of atoms induced by an energetic particle in a solid or liquid.

Stopping and Range of Ions in Matter (SRIM) is a group of computer programs which calculate interactions between ions and matter; the core of SRIM is a program called Transport of Ions in Matter (TRIM). SRIM is popular in the ion implantation research and technology community, and also used widely in other branches of radiation material science.

<span class="mw-page-title-main">Binary collision approximation</span> Heuristic used in simulations of ions passing through solids

In condensed-matter physics, the binary collision approximation (BCA) is a heuristic used to more efficiently simulate the penetration depth and defect production by energetic ions in solids. In the method, the ion is approximated to travel through a material by experiencing a sequence of independent binary collisions with sample atoms (nuclei). Between the collisions, the ion is assumed to travel in a straight path, experiencing electronic stopping power, but losing no energy in collisions with nuclei.

Ion milling is a specialized physical etching technique that is a crucial step in the preparation of material analysis techniques. After a specimen goes through ion milling, the surface becomes much smoother and more defined, which allows scientists to study the material much easier. The ion mill generates high-energy particles to remove material off the surface of a specimen, similar to how sand and dust particles wear away at rocks in a canyon to create a smooth surface. Relative to other techniques, ion milling creates much less surface damage, which makes it perfect for surface-sensitive analytical techniques. This article discusses the principle, equipment, applications, and significance of ion milling.

References

  1. ↑ Lobbia, R.B.; Polk, J.E.; Hofer, R.R.; Chaplin, V.H; Jorns, B. (2019-08-19). "Accelerating 23,000 hours of ground test backsputtered carbon on a magnetically shielded Hall thruster". AIAA Propulsion and Energy 2019 Forum. doi:10.2514/6.2019-3898. ISBN   978-1-62410-590-6.
  2. 1 2 3 R. Behrisch, ed. (1981). Sputtering by Particle bombardment. Springer, Berlin. ISBN   978-3-540-10521-3.
  3. ↑ "What is DC Sputtering?". 26 November 2016.
  4. ↑ P. Sigmund, Nucl. Instrum. Methods Phys. Res. B (1987). "Mechanisms and theory of physical sputtering by particle impact". Nuclear Instruments and Methods in Physics Research Section B. 27 (1): 1–20. Bibcode:1987NIMPB..27....1S. doi:10.1016/0168-583X(87)90004-8.
  5. 1 2 Behrisch, Rainer; Eckstein, Wolfgang, eds. (2007). Sputtering by Particle bombardment: Experiments and Computer Calculations from Threshold to Mev Energies. Springer, Berlin.
  6. ↑ M.W. Thompson (1962). "Energy spectrum of ejected atoms during the high- energy sputtering of gold". Phil. Mag. 18 (152): 377. Bibcode:1968PMag...18..377T. doi:10.1080/14786436808227358.
  7. ↑ J. F. Ziegler, J. P, Biersack, U. Littmark (1984). The Stopping and Range of Ions in Solids," vol. 1 of series Stopping and Ranges of Ions in Matter. Pergamon Press, New York. ISBN   978-0-08-021603-4.{{cite book}}: CS1 maint: multiple names: authors list (link)
  8. ↑ Mai Ghaly & R. S. Averback (1994). "Effect of viscous flow on ion damage near solid surfaces". Physical Review Letters. 72 (3): 364–367. Bibcode:1994PhRvL..72..364G. doi:10.1103/PhysRevLett.72.364. PMID   10056412.
  9. ↑ S. Bouneau; A. Brunelle; S. Della-Negra; J. Depauw; D. Jacquet; Y. L. Beyec; M. Pautrat; M. Fallavier; J. C. Poizat & H. H. Andersen (2002). "Very large gold and silver sputtering yields induced by keV to MeV energy Aun clusters (n=1–13)". Phys. Rev. B. 65 (14): 144106. Bibcode:2002PhRvB..65n4106B. doi:10.1103/PhysRevB.65.144106. S2CID   120941773.
  10. ↑ T. Schenkel; Briere, M.; Schmidt-Böcking, H.; Bethge, K.; Schneider, D.; et al. (1997). "Electronic Sputtering of Thin Conductors by Neutralization of Slow Highly Charged Ions". Physical Review Letters. 78 (12): 2481. Bibcode:1997PhRvL..78.2481S. doi:10.1103/PhysRevLett.78.2481. S2CID   56361399.
  11. ↑ Johnson, R. E.; Carlson, R. W.; Cooper, J. F.; Paranicas, C.; Moore, M. H.; Wong, M. C. (2004). Fran Bagenal; Timothy E. Dowling; William B. McKinnon (eds.). Radiation effects on the surfaces of the Galilean satellites. In: Jupiter. The planet, satellites and magnetosphere. Vol. 1. Cambridge, UK: Cambridge University Press. pp. 485–512. Bibcode:2004jpsm.book..485J. ISBN   0-521-81808-7.
  12. ↑ T. Neidhart; Pichler, F.; Aumayr, F.; Winter, HP.; Schmid, M.; Varga, P.; et al. (1995). "Potential sputtering of lithium fluoride by slow multicharged ions". Physical Review Letters. 74 (26): 5280–5283. Bibcode:1995PhRvL..74.5280N. doi:10.1103/PhysRevLett.74.5280. PMID   10058728. S2CID   33930734.
  13. ↑ M. Sporn; Libiseller, G.; Neidhart, T.; Schmid, M.; Aumayr, F.; Winter, HP.; Varga, P.; Grether, M.; Niemann, D.; Stolterfoht, N.; et al. (1997). "Potential Sputtering of Clean SiO2 by Slow Highly Charged Ions". Physical Review Letters. 79 (5): 945. Bibcode:1997PhRvL..79..945S. doi:10.1103/PhysRevLett.79.945. S2CID   59576101.
  14. ↑ F. Aumayr & H. P. Winter (2004). "Potential sputtering". Philosophical Transactions of the Royal Society A . 362 (1814): 77–102. Bibcode:2004RSPTA.362...77A. doi:10.1098/rsta.2003.1300. PMID   15306277. S2CID   21891721.
  15. ↑ G. Hayderer; Schmid, M.; Varga, P.; Winter, H; Aumayr, F.; Wirtz, L.; Lemell, C.; Burgdörfer, J.; Hägg, L.; Reinhold, C.; et al. (1999). "Threshold for Potential Sputtering of LiF" (PDF). Physical Review Letters. 83 (19): 3948. Bibcode:1999PhRvL..83.3948H. doi:10.1103/PhysRevLett.83.3948.
  16. ↑ T. A. Schoolcraft and B. J. Garrison, Journal of the American Chemical Society (1991). "Initial stages of etching of the silicon Si110 2x1 surface by 3.0-eV normal incident fluorine atoms: a molecular dynamics study". Journal of the American Chemical Society. 113 (22): 8221. doi:10.1021/ja00022a005.
  17. ↑ J. Küppers (1995). "The hydrogen surface chemistry of carbon as a plasma facing material". Surface Science Reports. 22 (7–8): 249–321. Bibcode:1995SurSR..22..249K. doi:10.1016/0167-5729(96)80002-1.
  18. ↑ E. Salonen; Nordlund, K.; Keinonen, J.; Wu, C.; et al. (2001). "Swift chemical sputtering of amorphous hydrogenated carbon". Physical Review B. 63 (19): 195415. Bibcode:2001PhRvB..63s5415S. doi:10.1103/PhysRevB.63.195415. S2CID   67829382.
  19. ↑ Farnsworth, H. E.; Schlier, R. E.; George, T. H.; Burger, R. M. (1955). "Ion Bombardment-Cleaning of Germanium and Titanium as Determined by Low-Energy Electron Diffraction". Journal of Applied Physics. 26 (2). AIP Publishing: 252–253. Bibcode:1955JAP....26..252F. doi:10.1063/1.1721972. ISSN   0021-8979.
  20. ↑ Farnsworth, H. E.; Schlier, R. E.; George, T. H.; Burger, R. M. (1958). "Application of the Ion Bombardment Cleaning Method to Titanium, Germanium, Silicon, and Nickel as Determined by Low-Energy Electron Diffraction". Journal of Applied Physics. 29 (8). AIP Publishing: 1150–1161. Bibcode:1958JAP....29.1150F. doi:10.1063/1.1723393. ISSN   0021-8979.
  21. ↑ G.S. Anderson and Roger M. Moseson, “Method and Apparatus for Cleaning by Ionic Bombardment,” U.S. Patent #3,233,137 (filed Aug. 28, 1961) (Feb.1, 1966)
  22. ↑ "Sputtering Targets | Thin Films". Admat Inc. Retrieved 2018-08-28.
  23. 1 2 Aydin, Erkan; Altinkaya, Cesur; Smirnov, Yury; Yaqin, Muhammad A.; Zanoni, Kassio P. S.; Paliwal, Abhyuday; Firdaus, Yuliar; Allen, Thomas G.; Anthopoulos, Thomas D.; Bolink, Henk J.; Morales-Masis, Monica (2021-11-03). "Sputtered transparent electrodes for optoelectronic devices: Induced damage and mitigation strategies". Matter. 4 (11): 3549–3584. doi: 10.1016/j.matt.2021.09.021 . hdl: 10754/673293 . ISSN   2590-2393. S2CID   243469180.
  24. ↑ Green, Julissa. "Exploring the Advantages and Disadvantages of Sputtering". Stanford Advanced Materials. Retrieved July 1, 2024.
  25. ↑ Raut, Hemant; Ganesh, V. (2011). "Anti-reflective coatings: A critical, in-depth review". Energy & Environmental Science. 4 (10): 3779-3804. doi:10.1039/C1EE01297E.
  26. ↑ Plats, Kelley (Oct 12, 2023). "The power of anti-reflective coatings on ig4 and ig6 substrates". NACL. Retrieved July 1, 2024.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.