Argon ion beam

In the field of microelectronics, there is continuing research in developing new materials to be used in semiconductor fabrication. They must be formed as thin films in a controlled, reproducible and uniform manner to be useful in semiconductor manufacturing applications. Depth profiling by AES is used to assess the properties of such films. The samples are sputtered with an argon ion beam and analysis performed using standard sensitivity factors, and it is possible to demonstrate that such films are uniform throughout a depth of, say, 250 nm. 

Ion Beam Deposition The most commonly used vacuum method for the rapid deposition of films (thin or thick) is sputtering (2M. This can be combined with ion beam techniques in a variety of ways (25) including (Figure 18) ion beam sputter deposition (IBSD) eg of oxide films or of hard carbon (26). In reactive systems the reactive gas is added to the argon ion beam. The properties of the deposited materials are modified substantially by varying the gas composition (Figure 19). 

Becker D, Bryant-Friedrich A, Trzasko C-A, Sevilla MD (2003) Electron spin resonance study of DNA irradiated with an argon-ion beam evidence for formation of sugar phosphate backbone radicals. Radiat Res 160 174-185... 

This method uses a laser for evaporating the boron compounds from a target (e.g., BN target). To regulate the flux of BN to the substrate the laser can be pulsed. Additionally, a nitrogen/argon ion-beam is generated and directed onto the substrate s surface. Various layers have been deposited, and the BN transition from substrate to the h-BN interlayer and finally to the nano-cBN has been studied in detail [203],... 

In a continuing study of ion-beam irradiation of hydrated DNA, both oxygen and argon ion-beams were used to investigate the radical yields and composition of the stabilized radical cohort in hydrated DNA at 77 K. For the argon ion-beam irradiated experiments, computer analysis of the DNA composite ESR spectra allowed quantification of the yields of G, T , C(N3)H and a mix of neutral (presumed) sugar radicals Qualitatively it is evident that XS ... 

Table 2. Yields of radicals in argon ion-beam irradiated and 7-irradiated hydrated DNA. ...

The relatively low overall yields of radicals were attributed to the high recombination rate of closely spaced base ion radicals in the densely ionized track core. The proximity of these radicals coupled with Coulomb attractions facilitates fast core ion radical-ion radical recombination. However, neutral sugar radicals in the core are not affected by Coulomb attractions, thus they do not recombine as readily. Therefore, most of the neutral sugar radicals stabilized at 77 K are presumed to form in the core. On the other hand, most of the base radicals that are stabilized at 77 K are assumed to form in the isolated, low LET-like spurs formed by delta-rays. The similarity in the behavior of the base radicals in argon ion-beam irradiated samples and in y irradiated samples lends support to this picture.In this model C(N3)H is in equilibrium with C and is found to act as an ion-radical. 

Fig. 2. Schematic of track of an Argon ion-beam in DNA. A high-energy density core is generated by deposition of ca. 50% of the energy of the ion in a relatively small volume. At 77 K, neutral sugar radicals are stabilized largely in the core. A much larger region of space formed by delta rays from the core is characterized by low LET-like spurs. Ion base radicals are stabilized in the spurs, with one-electron-reduced cytosine actually existing as a protonated species.

In argon ion-beam irradiated hydrated a sugar radical... 

Becker D, Bryant-Friedrich A, Trzasko C, Sevilla MD. (2003) Electton spin resonance study of DNA irradiated with an argon-ion beam Evidence for formation of sugar phosphate backbone radicals. Radiat Res 160 174-185. Becker D, Razskazovskii Y, Callaghan MU, Sevilla MD. (1996) Electton spin resonance of DNA irradiated with a heavy-ion beam ( O ) Evidence for damage to the deoxyribose phosphate backbone. Radiat Res 146 361-368. 

Golub MA. Concerning apparent similarity of structures of fluoropolymer surfaces exposed to an argon plasma or argon ion beam. Langmuir 1996 12 3360-3361. 

In industrial ion-beam sputter deposition, an argon ion beam, usually from a broad beam Kaufman-type ion source operating in dc or a high frequency mode... 

Table VIII presents the change in peak intensities minus background for alloy A exposed to saliva after a a hr argon ion beam etch.

Table VIII. Percent Change in SIMS Spectrum for Saliva Exposed Alloy A after Argon Ion Beam Etch...

High-quality films of TCOs have been fabricated by ion beam sputtering from oxide targets [173, 201] at deposition temperatures less than 100 °C. Fan [201] has used an argon-ion beam source with a typical value of current of 50 mA. 

Ion beam Substrate covered with polymer exposed to low energy argon ion beam. [23, 36]... 

S. Inokoshi, H. Hosoda, C. Harnirattisai, Y. Shimada, Interfacial structure between dentin and seven dentin bonding system revealed using argon ion beam etching. Open Dent, 18, 8-16,1993. 

The formation of ArN, observed mass spectrometrically in mixtures of Ar with N2 [16 to 18], probably occurs via (Nj) +Ar->ArN + N [16, 17]. ArN ions form in collisions of nitrogen with photoionized argon in the center-of-mass energy range of 8.2 to 41.2 eV. ArN is probably formed via a nearly coUinear arrangement Ar ---N-N [19]. In secondary ion mass spectra of solid N2 with a 4-keV argon ion beam, weak peaks were assigned to ArN and ArN, and a very weak peak to Ar(N2)J [1]. 

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