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.

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.

High rate etching of GaAs and GaP by gas cluster ion beams

2003 ◽  
Vol 792 ◽  
Author(s):  
Masahiro Nagano ◽  
Shingo Houzumi ◽  
Noriaki Toyoda ◽  
Susumu Yamada ◽  
Shirabe Akita ◽  
...  
Keyword(s):  
Cluster Size ◽  
Ion Beam ◽  
Ion Beams ◽  
High Rate ◽  
Cluster Ion Beams ◽  
Cluster Ion ◽  
New Processing ◽  
Gas Cluster Ion Beam ◽  
Ar Gas ◽  
Sputtering Yields

ABSTRACTGas cluster ion beam (GCIB) techniques have recently been proposed as new processing methods. We have been investigating the characteristics of GCIB techniques through sputtering GaAs and GaP by Ar gas cluster ion beams as a function of cluster size and acceleration energy. The Ar cluster size was selected by a magnetic spectrometer, and was obtained from the mass spectra measured by a time of flight mass spectrometer. The average sputtering yields of GaAs and GaP were 0–47 and 0–66 atoms/ion for 5–30 k V, respectively. The sputtering yields of GaAs and GaP were higher than those of an Ar monomer ion.

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.

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.

Cluster Ion Beam Process for Nanofabrication

2007 ◽  
Vol 1020 ◽  
Author(s):  
Isao Yamada ◽  
Noriaki Toyoda
Keyword(s):  
Ion Beam ◽  
Industrial Applications ◽  
Significant Events ◽  
Junction Formation ◽  
Cluster Ion Beams ◽  
Experimental Laboratory ◽  
Cluster Ion ◽  
Linear Effects ◽  
Gas Cluster Ion Beam ◽  
Cluster Beams

AbstractThis paper reviews gas cluster ion beam (GCIB) technology, including the generation of cluster beams, fundamental characteristics of cluster ion to solid surface interactions, emerging industrial applications, and identification of some of the significant events which occurred as the technology has evolved into what it is today. More than 20 years have passed since the author (I.Y) first began to explore feasibility of processing by gas cluster ion beams at the Ion Beam Engineering Experimental Laboratory of Kyoto University. Processes employing ions of gaseous material clusters comprised of a few hundred to many thousand atoms are now being developed into a new field of ion beam technology. Cluster-surface collisions produce important non-linear effects which are being applied to shallow junction formation, to etching and smoothing of semiconductors, metals, and dielectrics, to assisted formation of thin films with nano-scale accuracy, and to other surface modification applications.

High Quality Oxide Film Formation by 02 Cluster Ion Assisted Deposition Technique

1997 ◽  
Vol 504 ◽  
Author(s):  
J. Matsuo ◽  
W. Qin ◽  
M. Akizuki ◽  
T. Yodoshi ◽  
I. Yamada
Keyword(s):  
Kinetic Energy ◽  
Oxide Film ◽  
Film Formation ◽  
Ion Beam ◽  
Ion Beams ◽  
Flat Panel Display ◽  
Low Resistivity ◽  
Cluster Ion Beams ◽  
Cluster Ion ◽  
Oxygen Cluster

ABSTRACTA new oxide film formation technique using gas-cluster ion beams has been developed. 02 cluster ions were used to irradiate during the evaporation of metal atoms, and PbOx and In203 films were grown. At the acceleration voltages above 5 kV, polycrystalline PbOx films preferentially oriented to (111) were obtained. A significant smoothing effect was observed with an acceleration voltage as low as 1 kV. An average surface roughness of 0.9 nm was obtained at 7 kV. Oxygen cluster ion beams are also utilized to grow In203 films, which are widely used as conductive-transparent films in flat panel display. In203 was deposited on glass or silicon substrates with simultaneous irradiation with an oxygen cluster ion beam. Highly transparent (80%) and low resistivity (<4×10−4 Ωcm) films were obtained with 7keV oxygen cluster ion beams. Kinetic energy of above 3keV is necessary to obtain low resistivity films. These results clearly indicate that the kinetic energy of the cluster is effectively used to enhance oxidation on the surface without radiation damage, in spite of the high acceleration voltages.

Gas Cluster Ion Beam Technology for Nano-Fabrication

2012 ◽  
Vol 82 ◽  
pp. 1-8
Author(s):  
Noriaki Toyoda ◽  
Isao Yamada
Keyword(s):  
Ion Beam ◽  
Surface Region ◽  
Local Area ◽  
Industrial Applications ◽  
Ion Beams ◽  
Low Energy ◽  
Cluster Ions ◽  
Nano Fabrication ◽  
Cluster Ion ◽  
Gas Cluster Ion Beam

A gas cluster is an aggregate of a few to several thousands of gaseous atoms or molecules, and it can be accelerated to a desired energy after ionization. Since the kinetic energy of an atom in a cluster is equal to the total energy divided by the cluster size, a quite-low-energy ion beam can be realized. Although it is difficult to obtain low-energy monomer ion beams due to the space charge effect, equivalently low-energy ion beams can be realized by using cluster ion beams at relatively high acceleration voltages. Not only the low-energy feature but also the dense energy depositions at a local area are important characteristics of the irradiation by gas cluster ions. All of the impinging energy of a gas cluster ion is deposited at the surface region, and this dense energy deposition is the origin of enhanced sputtering yields, crater formation, shockwave generation, and other non-linear effects. GCIBs are being used for industrial applications where a nano-fabrication process is required. Surface smoothing, shallow doping, low-damage etching, trimming, and thin-film formations are promising applications of GCIBs. In this paper, fundamental irradiation effects of GCIB are discussed from the viewpoint of low-energy irradiation, sputtering, and dense energy depositions. Also, various applications of GCIB for nano-fabrications are explained.

Gas Cluster Ion Beam Processing of GaSb and InSb Surfaces

2003 ◽  
Vol 792 ◽  
Author(s):  
K. Krishnaswami ◽  
S.R. Vangala ◽  
B. Krejca ◽  
L.P. Allen ◽  
C. Santeufemio ◽  
...  
Keyword(s):  
Oxide Layer ◽  
Molecular Beam ◽  
Ion Beam ◽  
Total Charge ◽  
Surface Smoothing ◽  
Average Roughness ◽  
Molecular Beam Epitaxial ◽  
Cluster Ion ◽  
Gas Cluster Ion Beam ◽  
A Charge

ABSTRACTGas Cluster Ion Beam (GCIB) processing has recently emerged as a novel surface smoothing technique to improve the finish of chemical-mechanical polished (CMP) GaSb (100) and InSb (111) wafers. This technique is capable of improving the smoothness CMP surfaces and simultaneously producing a thin desorbable oxide layer for molecular beam epitaxial growth. By implementing recipes with specific gas mixtures, cluster energy sequences, and doses, an engineered oxide can be produced. Using GaSb wafers with a high quality CMP finish, we have demonstrated surface smoothing of GaSb by reducing the average roughness from 2.8Å to 1.7Å using a dual energy CF4/O2-GCIB process with a total charge fluence of 4×1015ions/cm2. For the first time, a GCIB grown oxide layer that is comprised of mostly gallium oxides which desorbed at 530°C in our molecular beam epitaxy system is reported, after which GaSb/AlGaSb epilayers have been successfully grown. Using InSb, we successfully demonstrated substrate smoothing by reducing the average roughness from 2.5Å to 1.6Å using a triple energy O2-GCIB process with a charge fluence 9×1015ions/cm2. In order to further demonstrate the ability of GCIB to smooth InSb surfaces, sharp ∼900nm high tips have been formed on a poorly mechanically polished InSb (111)A wafer and subsequently reduced to a height of ∼100nm, an improvement by a factor of eight, using a triple energy SF6/O2-GCIB process with a total charge fluence of 6×1016ions/cm3.

Sign in / Sign up

Export Citation Format

Share Document