Changes in Optical Transmittance of Aluminum Nitride thin Films Exposed to Air

1996 ◽  
Vol 449 ◽  
Author(s):  
Yoshifumi Sakuragi ◽  
Yoshihisa Watanabe ◽  
Yoshikazu Nakamura ◽  
Yoshiki Amamoto
Keyword(s):  
Thin Films ◽  
Aluminum Nitride ◽  
Ion Beam ◽  
Optical Transmittance ◽  
Optical Microscope ◽  
Constant Current ◽  
Reaction Products ◽  
Constant Current Density ◽  
Air Exposure ◽  
Nitrogen Ion

ABSTRACTAluminum nitride (AlN) thin films have been synthesized by ion-beam assisted deposition method and the influence of air-exposure on the optical transmittance has been studied. The kinetic energy of nitrogen ion beam was kept at 0.1 or 1.5 keV under the constant current density. Synthesized films have been exposed to controlled air (23 °C and RH; 50%) and optical transmission spectrum from 190 to 2200 nm has been measured by UV-visible spectrometer every week. Surface morphology of the films has been observed with an optical microscope (OM). The optical transmittance has not changed drastically up to one year. Observations by OM show that round features of some microns were produced on the surface after about 25 weeks exposure. These substances seem to be reaction products between AlN and water in air.

Microstructure and Optical Properties of Aluminum Nitride Thin Films

1995 ◽  
Vol 403 ◽  
Author(s):  
Yoshihisa Watanabe ◽  
Yoshikazu Nakamura ◽  
Shigekazu Hirayama ◽  
Yuusaku Naota
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Aluminum Nitride ◽  
Beam Energy ◽  
Ion Beam ◽  
Optical Measurements ◽  
Constant Current ◽  
Constant Current Density ◽  
Polycrystalline Aluminum ◽  
Nitrogen Ion

AbstractPolycrystalline aluminum nitride (AIN) thin films have been synthesized by ion-beam assisted deposition method and the effect of ion beam energy on the film structure and optical properties has been studied. The kinetic energy of nitrogen ion beam was varied from 0.05 to 1.5 keV under the constant current density. Microstructure of films was examined by thin film X ray diffraction (TFXRD) and optical transmission spectrum from 220 to 2200 nm was measured by UV-visible spectrometer. The TFXRD studies show that the (00*02) plane of hexagonal AIN grows preferentially with the ion beam energy of 0.05 keV and the intensity of the (10*0) and (10*1) planes becomes strong with increasing the ion beam energy. The optical measurements reveal that the wavy structures due to the interference effect are observed in the transmission spectra and the wavy pattern decreases with increasing the ion beam energy, resulting in the decrease of refractive index.

Changes in optical transmittance and surface morphology of AlN thin films exposed to atmosphere

1998 ◽  
Vol 13 (10) ◽  
pp. 2956-2961 ◽  
Author(s):  
Yoshihisa Watanabe ◽  
Yoshifumi Sakuragi ◽  
Yoshiki Amamoto ◽  
Yoshikazu Nakamura
Keyword(s):  
Thin Films ◽  
Elevated Temperature ◽  
Surface Morphology ◽  
Ion Beam ◽  
Wavelength Region ◽  
Film Surface ◽  
Optical Transmittance ◽  
Phase Identification ◽  
Reaction Products ◽  
Nitrogen Ion

Aluminum nitride (AlN) thin films have been prepared by the ion-beam assisted deposition (IBAD) method, and the influence of exposure to different atmosphere on optical transmittance and surface morphology has been studied. AlN films have been prepared with the nitrogen ion beam energy of 0.1, 0.2, or 1.5 keV. Synthesized films have been exposed to the following conditions: (i) laboratory air (RT and 40–60% RH), (ii) saturated humidity air (RT and 80–90% RH), and (iii) elevated temperature air (100 °C and 10–20% RH). Optical transmission spectrum in the wavelength region from 190 to 2200 nm has been measured by a UV-visible spectrometer every week. Surface morphology of the films has been observed with an optical microscope (OM), and phase identification has been performed by thin film x-ray diffraction (TFXRD). The optical transmittance has not changed drastically after exposure both to the laboratory air and the saturated humidity air for 60 weeks and after exposure to the elevated temperature air for 48 weeks. Observations by OM showed that round-shaped substances were formed on the film surfaces after exposure to the atmosphere, and the size of the substances on the film surface exposed to saturated humidity air is much larger than those on the surface exposed to other atmosphere. The results of TFXRD revealed that the AlN diffraction peaks have gradually decreased with exposure time, but any new phase due to reaction products has not been detected for the samples exposed to the laboratory air, the saturated humidity air, or the elevated temperature air. From the present results, it is concluded that the IBAD AlN films can be applied in low humidity air without losing high transparency up to 60 weeks, and the films prepared with 1.5 keV ion beam show better durability than the films prepared with 0.1 or 0.2 keV ion beam for exposure to the saturated humidity air.

Irradiation Effect of Nitrogen Ion Beam on Carbon Nitride Thin Films

2003 ◽  
Vol 792 ◽  
Author(s):  
Shinichiro Aizawa ◽  
Yuka Nasu ◽  
Masami Aono ◽  
Nobuaki Kitazawa ◽  
Yoshihisa Watanabe
Keyword(s):  
Thin Films ◽  
Carbon Nitride ◽  
Ion Beam ◽  
Chemical Vapor ◽  
Columnar Structure ◽  
Irradiation Effect ◽  
Carbon Filament ◽  
Cross Sectional ◽  
Nitrogen Ions ◽  
Nitrogen Ion

ABSTRACTIrradiation effect of low-energy nitrogen ion beam on amorphous carbon nitride (a-CNx) thin films has been investigated. The a-CNx films were prepared on silicon single crystal substrates by hot carbon-filament chemical vapor deposition (HFCVD). After deposition, the CNx films were irradiated by a nitrogen ion beam with energy from 0.1 to 2.0 keV. Irradiation effect on the film microstructure and composition was studied by SEM and XPS, focusing on the effect of nitrogen ion beam energy. Surface and cross sectional observations by SEM reveal that the as-deposited films show a densely distributed columnar structure and the films change to be a sparsely distributed cone-like structure after irradiation. It is also found that 2.0 keV ions skeltonize the films more clearly than 0.1 kev ions. Depth profiles of nitrogen in the films observed by XPS show that nitrogen absorption into films is more prominent after irradiation by 0.1 keV nitrogen ions than 2.0 keV ions.

Effect of Water on the IR Properties of Mg2+ Intercalated Electrochromic Nb2O5 Thin Films

2006 ◽  
Vol 972 ◽  
Author(s):  
Gargi Agarwal ◽  
G B Reddy
Keyword(s):  
Thin Films ◽  
Aqueous Solution ◽  
Water Content ◽  
Current Density ◽  
Sol Gel ◽  
Constant Current ◽  
Cyclic Stability ◽  
Constant Current Density ◽  
Effect Of Water ◽  
Ftir Studies

AbstractSol-gel derived Nb2O5 thin films were intercalated with Mg2+,using the non-aqueous solution of Mg(ClO4)2 in propylene carbonate (pc) as the electrolyte. 2% and 4% ( volume %) water was added to the electrolyte to study the effect of water on the electrochromic properties of Nb2O5. This paper presents the changes in optical and structural properties of the intercalated films with and without water in the electrolyte. The ratio (x) of the Mg2+ and Nb atoms has been controlled by optimizing the intercalation duration under a constant current density. The fall in transmittance on intercalation (for x= 0.8) increased by 15% with 4% water in the electrolyte, compared to the film intercalated without water. FTIR studies show that water is incorporated in the films on intercalation and small quantities of Mg(OH)2 and Nb-OH are formed along with Mg-O-Nb bonds. The presence of water in electrolyte decreases water content in the films and enhances the formation of Mg(OH)2, Mg-O-Nb and Nb-OH bonds. The recovery of Mg2+ on deintercalation is slightly reduced in presence of water in the electrolyte. The cyclic stability of the films intercalated without water is more than that of the films intercalated in presence of water.

Effect of Microstructure on Microhardness of AlN Thin Films

2001 ◽  
Vol 695 ◽  
Author(s):  
Shuichi Miyabe ◽  
Masami Aono ◽  
Nobuaki Kitazawa ◽  
Yoshihisa Watanabe
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Beam Energy ◽  
Ion Beam ◽  
Columnar Structure ◽  
Granular Structure ◽  
Nano Indentation ◽  
Ion Beam Assisted Deposition ◽  
Film Microstructure ◽  
Nitrogen Ion

ABSTRACTAluminum nitride (AlN) thin films with columnar and granular structures were prepared by ion-beam assisted deposition method by changing nitrogen ion beam energy, and the effects of the film microstructure and film thickness on their microhardness were studied by using a nano-indentation system with the maximum force of 3 mN. For the columnar structure film of 600 nm in thickness, the microhardness is found to be approximately 24 GPa when the normalized penetration depth to the film thickness is about 0.1. For the granular structure film of 700 nm in thickness, the microhardness is found to be approximately 14 GPa. These results reveal that the microhardness of the AlN films strongly depends on the film microstructure, which can be controlled by regulating the nitrogen ion beam energy.

Nitrogen‐ion irradiation during the deposition of C1−xNx thin films by ion beam sputtering technique

1996 ◽  
Vol 14 (3) ◽  
pp. 777-780 ◽  
Author(s):  
Satoshi Kobayashi ◽  
Keiko Miyazaki ◽  
Shinji Nozaki ◽  
Hiroshi Morisaki ◽  
Shigeo Fukui ◽  
...  
Keyword(s):  
Thin Films ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Ion Beam Sputtering ◽  
Beam Sputtering ◽  
Nitrogen Ion

Preparation of molybdenum nitride thin films by N+ ion implantation

1992 ◽  
Vol 7 (2) ◽  
pp. 374-378 ◽  
Author(s):  
J-G. Choi ◽  
D. Choi ◽  
L.T. Thompson
Keyword(s):  
Thin Films ◽  
Ion Beam ◽  
Substrate Surface ◽  
Molybdenum Nitride ◽  
X Ray Diffraction ◽  
Ion Energy ◽  
Ion Channeling ◽  
Ion Energies ◽  
Nitrogen Ions ◽  
Nitrogen Ion

A series of molybdenum nitride films were synthesized by implanting energetic nitrogen ions into molybdenum thin films. The resulting films were characterized using x-ray diffraction to determine the effects of nitrogen ion dose (4 × 1016−4 × 1017 N+/cm2), accelerating voltage (50–200 kV), and target temperature (∼298–773 K) on their structural properties. The order of structural transformation with increased incorporation of nitrogen ions into the Mo film can be summarized as follows: Mo → γ−Mo2N → δ−MoN. Nitrogen incorporation was increased by either increasing the dose or decreasing the ion energy. At elevated target temperatures the metastable B1–MoN phase was also produced. In most cases the Mo nitride crystallites formed with the planes of highest atomic density parallel to the substrate surface. At high ion energies preferential orientation developed so that the more open crystallographic directions aligned with the ion beam direction. We tentatively attributed this behavior to ion channeling effects.

Preparation of Aluminum Nitride and Oxynitride Thin Films by Ion-Assisted Deposition

1987 ◽  
Vol 93 ◽  
Author(s):  
J. D. Targove ◽  
L J. Lingg ◽  
J. P. Lehan ◽  
C. K. Hwangbo ◽  
H. A. Macleod ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Electron Beam ◽  
Aluminum Nitride ◽  
Oxygen Diffusion ◽  
Vacuum Chamber ◽  
Rutherford Backscattering Spectrometry ◽  
Ion Fluxes ◽  
Aluminum Oxynitride ◽  
Nitrogen Ion

ABSTRACTAluminum nitride thin films have been deposited by ion-assisted deposition. Aluminum was electron-beam evaporated onto substrates with simultaneous nitrogen ion bombardment. Rutherford backscattering spectrometry showed that nitrogen-to-aluminum ratios of one or greater could be achieved with sufficient nitrogen ion fluxes. This excess nitrogen apparently degrades the optical properties of the films in the visible. Annealing at 500°C improves the optical properties drastically at the expense of a slight oxygen diffusion into the films. Finally, aluminum oxynitride films were deposited by adding an oxygen backfill to the vacuum chamber during deposition. These films had very similar optical properties to the annealed nitride films.

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