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Volume 38, Issue 11
Displaying 1-11 of 11 articles from this issue
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Osamu FUKUMASA1995 Volume 38 Issue 11 Pages 903-910
Published: November 20, 1995
Released on J-STAGE: September 29, 2009
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Hiroshi AMEMIYA1995 Volume 38 Issue 11 Pages 911-917
Published: November 20, 1995
Released on J-STAGE: September 29, 2009
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Takamichi HIRATA, Rikizo HATAKEYAMA, Tetsu MIENO, Noriyoshi SATO1995 Volume 38 Issue 11 Pages 918-923
Published: November 20, 1995
Released on J-STAGE: January 28, 2010
JOURNAL FREE ACCESSAn ultrafine-particle plasma consisting of electrons, positive potassium ions, and large negative fullerence ions is produced by introducing “Buckminsterfullerence” particles into a low-temperature (≅0.2 eV) alkali plasma column confined by a stong axial magnetic field. The large Larmor radius of the fullerene modifies the radial and axial structure in the plasma. Mass spectra obtained yield negative ion components C60 and C70 with a density ratio of C70 to C60 = 0.08 0.1. With an increase in the fullerence ion fraction, the electron shielding decreases, yielding clear effects on plasma collective phenomena such as plasma-wave propagations and instabilities. This plasma source is expected to be useful for producing new fullerene-based materials.View full abstractDownload PDF (2602K) -
Haruo SHINDO, Yoshio SAWA, Yasuhiro HORIIKE1995 Volume 38 Issue 11 Pages 924-928
Published: November 20, 1995
Released on J-STAGE: September 29, 2009
JOURNAL FREE ACCESSFor a feasibility study of plasma etching employing bipolar, Si etching by negative ions was studied in SF6 plasma. Negative ions were confirmed to be present by Langmuir probe measurements of ion currents, in which the current ratio of ions of both polarities became approximately unity in a bownstream region at pressures above 90 mTorr. In this downstream region, Si etching was observed not only at negative DC bias but also at positive bias, indicating that negative ion etching occurred. Based on the above results, n+poly-Si patterned with lines and spaces was etched in the downstream region under the condition of 100 kHz RF bias which allowed the alternate irradiations of positive and negative ions. It was found that the amount of side etch was reduced under the condition of negative ion irradiation.View full abstractDownload PDF (738K) -
Kanenaga FUJII, Yuji HORINO, Nobuteru TSUBOUCHI, Akiyoshi CHAYAHARA, A ...1995 Volume 38 Issue 11 Pages 929-934
Published: November 20, 1995
Released on J-STAGE: September 29, 2009
JOURNAL FREE ACCESSWe have developed a novel dual-ion-beam direct deposition apparatus. The machine consists of a positive ion beam line, a negative ion beam line and an ultrahigh-vacuum deposition chamber. The machine can generate mass-analyzed very-low-energy ion beams with positive and negative charges at the same time. It is possible to deposit both types of ions not only simultaneously but also alternately. The apparatus is called the TAOTRON and its nickname is PANDA (Positive And Negative ion Deposition Apparatus). Ion energy range is from 10 eV to 20 keV. Typical ion beam current is ≥10 μA depending on ion species. The base pressure of the deposition is on the order of 10-8 Pa and the pressure during deposition is on the order of 10-6 Pa. The machine has the potential to fabricate a wide range of ultrapure metals, semiconductors, insulators and other interesting materials such as c-BN, diamondlike carbon and SiC. It is also useful for the study of fundamental processes of ion beam deposition and/or ion-solid surface interactions.View full abstractDownload PDF (1070K) -
Hiroshi MORISAKI, Shinji NOZAKI1995 Volume 38 Issue 11 Pages 935-942
Published: November 20, 1995
Released on J-STAGE: September 29, 2009
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Yasuhiro SUGAWARA, Masahiro OHTA, Hitoshi UEYAMA, Seizo MORITA1995 Volume 38 Issue 11 Pages 943-948
Published: November 20, 1995
Released on J-STAGE: September 29, 2009
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Kenichi KAWAGUCHI, Tadataka MORISHITA1995 Volume 38 Issue 11 Pages 949-954
Published: November 20, 1995
Released on J-STAGE: September 29, 2009
JOURNAL FREE ACCESSWe have developed a mass-separated low-energy oxygen ion (O+) beam as an oxygen source for molecular beam epitaxy growth of oxide thin films in ultrahigh vacuum. As an application of this technique to oxide superconductors, Sr-Cu-O infinite-layer (IL) films were grown by alternate atomic-layer deposition of Sr and Cu. Sr- and Cu-terminated IL films exhibit different reconstruction patterns in reflection high-energy electron diffraction (RHEED), suggesting that the film growth proceeds by repetition of these two reconstructions at surfaces. The films have high crystallinity, which is demonstrated by Kikuchi lines in RHEED patterns and by X-ray diffraction rocking curves with a full width at half-maximum of 0.016°. Mass spectral analysis of residual gas during the growth showed that the films grow under an extremely low background partial pressure of molecular oxygen (<3×10-9 Pa).View full abstractDownload PDF (996K) -
Tetsuo FUKADA, Makiko HASEGAWA, Takeshi MORI, Yoshihiko TOYODA, Noboru ...1995 Volume 38 Issue 11 Pages 955-961
Published: November 20, 1995
Released on J-STAGE: September 29, 2009
JOURNAL FREE ACCESSCu has become the subject of major interest as a promising interconnection material because it has lower resistivity than Al. However, Cu is oxidized more easily than Al. In this study, we have investigated the dependence of the Cu oxidation on heat treatment temperature, and five materials, Ti, TiN, Cr, TiW, and TiWN, were examined as candidates for an oxidation-barrier metal on the Cu films.
The Cu film was oxidized at temperatures higher than 170°C in air. Among the five materials, the Cr and TiWN films acted as good barrier metals to prevent the xygen diffusion. However, hillocks were observed at Cr surface after sputtering deposition process, and the surface morphology was degraded after heat treatment. Consequently, TiWN is considered to be the best barrier metal.
We used the TiWN films to fabricate a fine TiWN/Cu/TiWN multilayer interconnection. We then confirmed that the TiWN film acted as a barrier metal to prevent Cu oxidation during the resist ashing process, and that ECR plasma-CVD was a useful method of depositing passivation SiO2 film on the interconnection without oxidizing the Cu surface.View full abstractDownload PDF (1384K) -
Youji KAWASAKI, Taketo TAKAHASHI, Takashi MURAKAMI, Yasuji MATSUI1995 Volume 38 Issue 11 Pages 962-970
Published: November 20, 1995
Released on J-STAGE: September 29, 2009
JOURNAL FREE ACCESSFabrication of shallow junctions is required for devices with smaller dimensions. However, it is difficult to form a shallow p+n junction by boron implantation and furnace annealing. Two important phenomena, of boron ion channeling and redistribution during annealing, must be suppressed.
In this paper, the effect of nitrogen pre-ion implantation on suppressing channeling and boron diffusion is described. Electrical characteristics of a p+n junction formed ny this technique are also investigated. Finally, we show that this technique has been successfully applied to the formation of a junction of depth 0.1 μm required for PMOSFET with 0.25 μm gate length.View full abstractDownload PDF (1534K) -
Takahiro YUMURA, Shigemitsu NAKANISHI, Kenji UMEZAWA1995 Volume 38 Issue 11 Pages 971-977
Published: November 20, 1995
Released on J-STAGE: September 29, 2009
JOURNAL FREE ACCESSSurface structures of Li/Cu (110) at 300 K were investigated by means of impact collision ion scattering spectroscopy (ICISS) and low-energy electron diffraction (LEED). A series of LEED patterns, (1×2), (1×1), (4×1), (5×1), and (n×1) where n < 8, were observed with an increase of Li coverage. The (1×2) structure is assigned to a missingrow-type restructuring of the Cu substrate atom induced by Li adsorption. The sequential structures of (4×1), (5×1) and so on were considered to belong to the same category, for which the structural model consists of Li atoms partially substituting for topmost Cu atoms and Li adatoms located in fourfold hollow sites on remaining Cu atoms.View full abstractDownload PDF (1420K)
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