Ultra Shallow Junction Formation by Cluster Ion Implantation

1998 ◽  
Vol 532 ◽  
Author(s):  
Jiro Matsuo ◽  
Takaaki Aoki ◽  
Ken-ichi Goto ◽  
Toshihiro Sugii ◽  
Isao Yamada

ABSTRACTImplantation of B cluster ions into Si using decaborane (B10H14) has been demonstrated. SIMS measurements show that the depth distribution of boron atoms implanted with a monomer ion is exactly matched by that of boron atoms implanted from decaborane ions, if the cluster ion has an order of magnitude larger acceleration energy. According to the Langmuir-Child equation, two orders of magnitude larger space-charge limited ion beam current is possible when decaborane ions are used. Implanted boron atoms from decaborane ions are electrically activated after annealing. Junction depth of the implanted layer with 3 keV decaborane ions is approximately 20nm after annealing at 900°C. Molecular dynamic caluculations show that implantation efficency of boron monomer ions and decaborane ions are the same. However, the number of displaced silicon atoms per implanted boron atom from a decaborane ion impact is 4 times larger than that by boron monomer impact so that a heavily damaged region is created near the impact zone by decaborane ion penetration.

1997 ◽  
Vol 504 ◽  
Author(s):  
T. Seki ◽  
M. Tanomura ◽  
T. Aoki ◽  
J. Matsuo ◽  
I. Yamada

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.


2004 ◽  
Vol 843 ◽  
Author(s):  
Toshio Seki ◽  
Jiro Matsuo

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.


1996 ◽  
Vol 427 ◽  
Author(s):  
I. Yamada ◽  
J. Matsuo

AbstractUnique characteristics of gas cluster ion beam bombardment are discussed in terms of ULSI fabrication processes. Cluster ion beams consisting of a few hundreds to thousands of atoms have been generated from various kinds of gas materials. Multi-collisions during the impact of accelerated cluster ions upon the substrate surfaces produce fundamentally low energy bombarding effects in a range of a few eV to hundreds of eV per atom at very high density. These bombarding characteristics can be applied to shallow ion implantation, high yield sputtering and smoothing, surface cleaning and low temperature thin film formation.


2000 ◽  
Vol 647 ◽  
Author(s):  
Toshio Seki ◽  
Kazumichi Tsumura ◽  
Takaaki Aoki ◽  
Jiro Matsuo ◽  
Gikan H. Takaoka ◽  
...  

AbstractNew surface modification processes have been demonstrated using gas cluster ion irradiations because of their unique interaction between cluster ions and surface atoms. For example, high quality ITO films could be obtained by O2 cluster ion assisted deposition at room temperature. It is necessary to understand the role of cluster ion bombardment during film formation for the further developments of this technology. Variable Temperature Scanning Tunneling Microscope (VT-STM) in Ultra High Vacuum (UHV) allows us to study ion bombardment effects on surfaces and nucleation growth at various temperatures.The irradiation effects between Ar cluster ion and Xe monomer ion were compared. When a Si(111) surface with Ge deposited to a few Å was annealed to 400°C, it was observed that many islands of Ge were formed. The surface with the Ge islands was irradiated by these ions. In the STM image of cluster-irradiated surface, large craters with diameter of about 100 Å were observed, while only small traces with diameter of about 20 Å were observed in monomer-irradiated surface. The number of Ge atoms displaced by one Ar cluster ion impact was much larger than that by one Xe ion impact. This result indicates that Ar cluster ion impacts can enhance the physical modification of Ge islands. When the sample irradiated with Ar cluster was annealed at 600°C, the hole remained, but the outer rim of the crater disappeared and the surface structure was reconstructed at the site of the rim. The depth of damage region in the target became shallower with decrease of the impact energy. These results indicate that low damage and useful surface modification can be realized using the cluster ion beam.


1996 ◽  
Vol 03 (01) ◽  
pp. 1017-1021 ◽  
Author(s):  
J. MATSUO ◽  
M. AKIZUKI ◽  
J. NORTHBY ◽  
G.H. TAKAOKA ◽  
I. YAMADA

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.


1999 ◽  
Vol 585 ◽  
Author(s):  
D. Fathy ◽  
O. W. Holland ◽  
R. Liu ◽  
J. Wosik ◽  
W. K Chu

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.


2007 ◽  
Vol 1020 ◽  
Author(s):  
Isao Yamada ◽  
Noriaki Toyoda

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.


2012 ◽  
Vol 82 ◽  
pp. 1-8
Author(s):  
Noriaki Toyoda ◽  
Isao Yamada

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.


2000 ◽  
Vol 647 ◽  
Author(s):  
Noriaki Toyoda ◽  
Jiro Matsuo ◽  
Takaaki Aoki ◽  
Shunichi Chiba ◽  
Isao Yamada ◽  
...  

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.


Author(s):  
И.В. Николаев ◽  
Н.Г. Коробейщиков ◽  
М.А. Роенко ◽  
П.В. Гейдт ◽  
В.И. Струнин

The possibility of surface modification of thin polycrystalline aluminum nitride films by bombardment with argon cluster ion beam is investigated. The processing was carried out with high- (105 eV/atom) and low-energy (10 eV/atom) cluster ions. Using the spectral function of roughness, a highly efficient smoothing of the surface of nanostructured thin films of aluminum nitride was demonstrated in a wide range of spatial frequencies (ν = 0.02–128 μm-1) and at small etching depth (<100 nm).


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