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.

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.

Optical thin film formation by gas-cluster ion beam assisted deposition

1999 ◽  
Author(s):  
H. Katsumata ◽  
J. Matsuo ◽  
T. Nishihara ◽  
T. Tachibana ◽  
K. Yamada ◽  
...  
Keyword(s):  
Thin Film ◽  
Film Formation ◽  
Ion Beam ◽  
Optical Thin Film ◽  
Ion Beam Assisted Deposition ◽  
Cluster Ion ◽  
Thin Film Formation ◽  
Gas Cluster Ion Beam

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.

Surface Smoothing Effects of Materials Used in Underlayer of MTJ with Gas Cluster Ion Beams

MRS Advances ◽  
2016 ◽  
Vol 1 (5) ◽  
pp. 357-362 ◽  
Author(s):  
Noriaki Toyoda
Keyword(s):  
Surface Roughness ◽  
Ion Beam ◽  
Random Access ◽  
Resistive Random Access Memory ◽  
Surface Smoothing ◽  
Smoothing Effects ◽  
Cluster Ion Beams ◽  
Cluster Ion ◽  
Materials Used ◽  
Gas Cluster Ion Beam

ABSTRACTSurface smoothing of Ru used as underlayer of magnetic tunneling junctions (MTJ) in magneto-resistive random access memory (MRAM) was carried out with gas cluster ion beam (GCIB) in order to improve device characteristics. For Ru films, surface smoothing with 5 kV N2-GCIB irradiation was effective, and CoFe films deposited on smoothed Ru surface also showed smooth surface. From the hysteresis loop measurements of MTJ formed on smoothed Ru with N2-GCIB, it showed improvement of inter-layer coupling magnetic field (Hin) with decreasing the surface roughness of underlayer Ru. It is expected that surface roughness of MgO in MTJ was also improved by smoothing of underlayer Ru with N2-GCIB.

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.

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