Application of Cluster Ion Beam Smoothing to SiC and YBCO Surfaces

1999 ◽  
Vol 585 ◽  
Author(s):  
D. Fathy ◽  
O. W. Holland ◽  
R. Liu ◽  
J. Wosik ◽  
W. K Chu
Keyword(s):  
Surface Topography ◽  
Ion Irradiation ◽  
Ion Beam ◽  
High Temperature Superconductors ◽  
Cluster Ions ◽  
Microwave Surface Resistance ◽  
Average Roughness ◽  
Cross Sectional ◽  
Cluster Ion Beams ◽  
Cluster Ion

AbstractOptimization of the surface topography, especially in high-temperature superconductors (HTS) and silicon carbide is crucial for device processing. Surface smoothing in these materials was investigated using Gas Cluster Ion Beams (GCIB) capable of delivering cluster ions of ≥ 2000 Ar atoms with energies of up to 30keV. Examination of the surface topography after cluster-ion irradiation was done using cross-sectional transmission electron microscopy (TEM) and atomic force microscopy (AFM). The results indicate that typical as-deposited YBCO films on MgO substrates have an average roughness of the order of 40 nm, and interpeak distance between 300–600 nm. Application of GCIB to the surface planarization reduces the roughness to only 10 nm. Also power handling and microwave surface resistance of the YBCO film and its relationship to surface smoothness are reported. Similar observations using bulk SiC are discussed.

SPUTTERING WITH GAS CLUSTER-ION BEAMS

1996 ◽  
Vol 03 (01) ◽  
pp. 1017-1021 ◽  
Author(s):  
J. MATSUO ◽  
M. AKIZUKI ◽  
J. NORTHBY ◽  
G.H. TAKAOKA ◽  
I. YAMADA
Keyword(s):  
Ion Irradiation ◽  
Removal Rate ◽  
Ion Beam ◽  
Solid Surfaces ◽  
Silicon Surfaces ◽  
Cluster Ions ◽  
Mass Filter ◽  
Cluster Bombardment ◽  
Cluster Ion Beams ◽  
Cluster Ion

A high-current (~100 nA) cluster-ion-beam equipment with a new mass filter has been developed to study the energetic cluster-bombardment effects on solid surfaces. A dramatic reduction of Cu concentration on silicon surfaces has been achieved by 20-keV Ar cluster (N~3000) ion bombardment. The removal rate of Cu with cluster ions is two orders of magnitude higher than that with monomer ions. A significantly higher sputtering yield is expected for cluster-ion irradiation. An energetic cluster-ion beam is quite suitable for removal of metal.

High-speed Processing with Cluster Ion Beams

2003 ◽  
Vol 792 ◽  
Author(s):  
Toshio Seki ◽  
Jiro Matsuo
Keyword(s):  
High Speed ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Ion Beams ◽  
High Rate ◽  
Cluster Ions ◽  
Cluster Ion Beams ◽  
Cluster Ion ◽  
Sputtering Yield ◽  
Reactive Cluster

ABSTRACTCluster ion beam processes can produce high rate sputtering with low damage in comparison with monomer ion beam processes. Especially, it is expected that extreme high rate sputtering can be obtained using reactive cluster ion beams. High current SF6 cluster ion beams were recently obtained with new modifications in the basic cluster ion beam technique. The cluster size distribution was measured with Time-of-Flight (TOF) method and the mean size of cluster was about 500 molecules. Si substrates were irradiated with SF6 cluster ions at the acceleration energy of 5–45 keV. Sputtering yield with SF6 cluster ions was increased with acceleration energy and was about 2300 atoms/ion at 45 keV. The sputtering yield was about 1000 times higher than that of Ar monomer ions and was also higher than that of Ar cluster ions. It was found that reactive sputtering occurred with SF6 cluster ion irradiation. These results indicate that high-speed fabrication can be realized with reactive cluster ion irradiation at high energy.

Improvement of surface roughness by ultra-thin film deposition with oxygen cluster ion beam assist deposition

2002 ◽  
Vol 749 ◽  
Author(s):  
Noriaki Toyoda ◽  
Isao Yamada
Keyword(s):  
Surface Roughness ◽  
Morphological Evolution ◽  
Ion Beam ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Average Roughness ◽  
Original Surface ◽  
Cluster Ion Beams ◽  
Cluster Ion ◽  
Gas Cluster Ion Beam

ABSTRACTTa2O5 films were deposited on a rough surface (average roughness 1.3nm, peak-to-valley 14nm) and surface roughness evolutions and improvements by O2 gas cluster ion beam (O2-GCIB) assisted deposition was studied. The average roughness dramatically decreased from 1.3nm to 0.5nm after deposition of Ta2O5 films 20nm in thickness with 7 keV of O2 cluster ion beams. As there was no etching or sputtering of Ta2O5 film by 7keV O2-GCIB irradiations, O2-GCIB assist deposition realized significant improvement of surface roughness by additional deposition of Ta2O5 film whose thickness was close to the peak-to-valley of original surface. It is expected that morphological evolution of the film by GCIB assist deposition becomes completely different from conventional ion assist deposition due to energetic cluster ion impacts.

Secondary Ion Mass Spectrometry with Gas Cluster Ion Beams

2000 ◽  
Vol 647 ◽  
Author(s):  
Noriaki Toyoda ◽  
Jiro Matsuo ◽  
Takaaki Aoki ◽  
Shunichi Chiba ◽  
Isao Yamada ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Secondary Ion Mass Spectrometry ◽  
Ion Beam ◽  
Md Simulations ◽  
Ion Beams ◽  
Cluster Ions ◽  
Ion Mass Spectrometry ◽  
Cluster Ion Beams ◽  
Cluster Ion ◽  
Secondary Ion

AbstractSecondary Ion Mass Spectrometry (SIMS) with Gas Cluster Ion Beams (GCIB) was studied with experiments and molecular dynamics (MD) simulations to achieve a high-resolution depth profiling. For this purpose, it is important to prevent both ion-mixing and the surface roughening due to energetic ions. As the Ar cluster ion beam shows surface smoothing effects and high secondary-ion yield in the low-energy regime, the cluster ion beam would be suitable for the primary ion beam of SIMS. From MD simulations of Ar cluster ion impact on a Si substrate, the ion-mixing is heavier than for Ar monomer ions at the same energy per atom, because the energy density at the impact point by clusters is extremely high. However, the sputtering yields with Ar cluster ions are one or two orders of magnitude higher than that with Ar monomer ions at the same energy per atom. Comparing at the ion energy where the ion-mixing depths are the same by both cluster and monomer ion impacts, cluster ions show almost ten times higher sputtering yield than Ar monomer ions. Preliminary experiment was done with a conventional SIMS detector and a mass resolution of several nm was achieved with Ar cluster ions as a primary ion beam.

Size Dependence of Bombardment Characteristics Produced by Cluster Ion Beams

1997 ◽  
Vol 504 ◽  
Author(s):  
T. Seki ◽  
M. Tanomura ◽  
T. Aoki ◽  
J. Matsuo ◽  
I. Yamada
Keyword(s):  
Ion Beam ◽  
Local Area ◽  
Carbon Cluster ◽  
High Rate ◽  
Cluster Ions ◽  
Scanning Tunneling ◽  
Cluster Ion Beams ◽  
Cluster Ion ◽  
Ion Impact ◽  
The Impact

ABSTRACTCluster ion beam processes provide new surface modification techniques, such as surface smoothing, high rate sputtering and very shallow implantation, because of the unique interactions between cluster and surface atoms. To understand interactions with cluster and surface, Scanning Tunneling Microscope (STM) observations have been done for single impact traces.Highly Oriented Pyrolitic Graphite (HOPG) surfaces were bombarded by carbon cluster ions (Va≤300kV), and large ridges and craters have been observed as a result of single cluster ion impact. The impact site diameters are proportional to the cluster size up to 10 atoms, and increase drastically for cluster sizes above 10. This indicates that non-linear multiple collisions occur only when a local area is bombarded by more than 10 atoms at the same time.

Surface Smoothing of Polycrystalline Si Waveguides With Gas-Cluster Ion Beams

1999 ◽  
Vol 597 ◽  
Author(s):  
N. Toyoda ◽  
K. K. Lee ◽  
H-C. Luan ◽  
D. R. Lim ◽  
A. M. Agarwal ◽  
...  
Keyword(s):  
Rough Surface ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Three Dimensional ◽  
Optical Loss ◽  
Surface Smoothing ◽  
Multilayered Structures ◽  
Average Roughness ◽  
Scattering Loss ◽  
Cluster Ion

AbstractPolycrystalline Si (poly-Si) waveguides offer design flexibility and multilayered structures in Si-integrated photonic devices. However, as-deposited poly-Si surfaces are rough compared with single-crystalline Si, and a rough surface causes significant waveguide scattering loss at the surface. In this study, surface smoothing of poly-Si waveguides with a gas-cluster ion beam (GCIB) was demonstrated as a new smoothing technique. As the GCIB process is a directional ion-beam process, in principle it can be applied not only to plane surfaces but also to three-dimensional or non-flat structures, such as waveguide ridges.The initial average roughness of as-deposited poly-Si films (625°C, 1 μm thick) ranged from 15 nm to 22 nm, and the grain sizes were distributed from 0.2 to 0.4μm. This rough surface was dramatically smoothed to a roughness of 1.5 nm by Ar cluster ion irradiation. From the relation between the sputtered depth and the surface roughness, the sputtered depth must be greater than the height difference of the roughness (peak-to-valley) to obtain smooth surfaces. Optical transmission losses at λ =1.54 μm were measured using cutback measurement from samples before and after the smoothing by GCIB. After surface smoothing with GCIB, the optical loss decreased from 85 dB/cm to 54 dB/cm.

High-speed Processing with Reactive Cluster Ion Beams

2004 ◽  
Vol 843 ◽  
Author(s):  
Toshio Seki ◽  
Jiro Matsuo
Keyword(s):  
High Speed ◽  
Ion Beam ◽  
Beam Current ◽  
Ion Beams ◽  
High Rate ◽  
Cluster Ions ◽  
Cluster Ion Beams ◽  
Cluster Ion ◽  
Sputtering Yield ◽  
Reactive Cluster

ABSTRACTCluster ion beam processes can produce high rate sputtering with low damage in comparison with monomer ion beam processes. Especially, it is expected that extreme high rate sputtering can be obtained using reactive cluster ion beams. Reactive cluster ion beams, such as SF6, CF4, CHF3, and CH2F2, were generated and their cluster size distributions were measured using Time-of-Flight (TOF) method. Si substrates were irradiated with the reactive cluster ions at the acceleration energy of 5–65 keV. Each sputtering yield was increased with acceleration energy and was about 1000 times higher than that of Ar monomer ions. The sputtering yield of SF6 cluster ions was about 4600 atoms/ion at 65 keV. With this beam, 12 inches wafers can be etched 0.5 μm per minute at 1 mA of beam current. The TOF measurement showed that the size of SF6 cluster was about 550 molecules and the number of fluorine atoms in a SF6 cluster was about 3300. If the sputtered product was SiF, the yield has to be less than 3300 atoms/ion. These results indicate that the reactive cluster ions etch targets not only chemically, but also physically. This high-speed processing with reactive cluster ion beam can be applied to fabricate nano-devices.

Lateral Sputtering by Gas Cluster Ion Beams and its Applications to Atomic Level Surface Modification

1995 ◽  
Vol 396 ◽  
Author(s):  
Isao Yamada ◽  
Jiro Matsuo
Keyword(s):  
Ion Beam ◽  
High Vacuum ◽  
Surface Cleaning ◽  
Ion Beams ◽  
Dynamics Simulation ◽  
Average Roughness ◽  
Cluster Ion Beams ◽  
Cluster Ion ◽  
Gas Cluster Ion Beam ◽  
Ion Size

AbstractGas cluster ion beam equipment (max. voltage 30kV) for sputtering has been developed. Cluster ion beams from gaseous materials such as Ar, O2, N2 and compound materials such as SF6, N2O, CO2 can be generated by expanding them through a Laval nozzle into a high-vacuum region. With this equipment sputtering process fundamentals have been studied. One of the unique characteristics of gas cluster ion bombardment is lateral sputtering. This is shown experimentally by measuring the angular distribution of sputtered atoms and is predicted by molecular dynamics simulation. Dependencies of sputtering yield (10-1000 times higher than for the monomer ion case) on cluster ion size and on ion beam energy for different substrate surfaces have been obtained. Examples of surface smoothing (typically less than 1 nm average roughness) on metals, semiconductors and insulators and of surface cleaning are presented.

Smoothing Thin Films with Gas-Cluster Ion Beams

2000 ◽  
Vol 614 ◽  
Author(s):  
D.B. Fenner ◽  
J. Hautala ◽  
L.P. Allen ◽  
J.A. Greer ◽  
W.J. Skinner ◽  
...  
Keyword(s):  
Thin Film ◽  
Ion Beam ◽  
Spin Valve ◽  
High Spatial Frequency ◽  
Atomic Scale ◽  
Force Microscopy ◽  
Tantalum Films ◽  
Cluster Ion Beams ◽  
Cluster Ion ◽  
Gas Cluster Ion Beam

ABSTRACTThin-film magnetic sensor and memory devices in future generations may benefit from a processing tool for final-step etching and smoothing of surfaces to nearly an atomic scale. Gas-cluster ion-beam (GCIB) systems make possible improved surface sputtering and processing for many types of materials. We propose application of GCIB processing as a key smoothing step in thin-film magnetic-materials technology, especially spin-valve GMR. Results of argon GCIB etching and smoothing of surfaces of alumina, silicon, permalloy and tantalum films are reported. No accumulating roughness or damage is observed. The distinct scratches and tracks seen in atomic-force microscopy of CMP-processed surfaces, are removed almost entirely by subsequent GCIB processing. The technique primarily reduces high spatial-frequency roughness and renders the topographic surface elevations more nearly gaussian (randomly distributed).

Etching and Surface Smoothing with Gas-Cluster Ion Beams

1999 ◽  
Vol 585 ◽  
Author(s):  
D. B. Fenner ◽  
R. P. Torti ◽  
L. P. Allen ◽  
N. Toyoda ◽  
A. R. Kirkpatrick ◽  
...  
Keyword(s):  
Surface Science ◽  
Ion Beam ◽  
Surface Processing ◽  
Figures Of Merit ◽  
Cluster Ion Beams ◽  
Cluster Ion ◽  
Gas Clusters ◽  
Gas Cluster Ion Beam ◽  
Microelectronic Materials ◽  
Very High

AbstractSurface processing of microelectronic materials by bombardment with nanoparticles of condensed gases (i.e., clusters) in the form of an ion beam, makes possible etching and smoothing of those surfaces to very high figures of merit. As this is not possible with any conventional ion method, gas-cluster ion-beam systems have great potential in manufacturing. The formation of gas clusters and their collision with surfaces provides an interesting arena for novel physics and surface science. This paper outlines a physical model for the clusters and surface interactions, and provides examples of surface processing. In particular, the reduction of surface roughness while etching by cluster-ion bombardment is illustrated for various materials utilized in microelectronics.

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