• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.10
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• pp.778-783
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• 1998

Film characteristics of thin ONO dielectric layers for MONOS(metal-oxide-nitride-oxide-semiconductor) EEPROM was investigated by TEM, AES and AFM. Seocnd derivative spectra of Auger Si LVV overlapping peak provide useful information fot chemical state analysis of superthin film. The ONO film with dimension of tunnel oxide 23$\AA$, nitride 33$\AA$, and blocking oxide 40$\AA$ was fabricated. During deposition of the LPCVD nitride film on tunnel oxide, this thin oxide was nitrized. When the blocking oxide was deposited on the nitride film, the oxygen not only oxidized the nitride surface, but diffused through the nitride. The results of ONO film analysis exhibits that it is made up of $SiO_2$ (blocking oxide)/O-rich SiON(interface)/N-rich SiON(nitride)/ O-rich SiON(tunnel oxide)

• Journal of the Korean institute of surface engineering
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• v.53 no.1
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• pp.36-42
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• 2020

In this study, two novel methods to measure the surface hardness of anodic oxide films on aluminum alloys are reported. The first method is to impregnate oil-based ink into pores in the anodic oxide film and then to clean the ink on the surface using ethanol, resulting in an impregnation of inks only inside of the pores in anodic oxide film. The second method is to coat the anodic oxide film surface with thin Au layer less than 0.1 ?. Both the ink-impregnating method and Au-coating method provided clear indentation marks on the anodic oxide film surface when it was indented using a pyramidal-diamond penetrator. Thus, Vickers hardness of anodic oxide films on aluminium alloy could be measured successfully and precisely from the anodic film surface. In addition, advantages and disadvantages of the ink-impregnating method and Au-coating method for the measurement of surface hardness of anodic oxide films are discussed.

• Journal of the Korean Vacuum Society
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• v.1 no.1
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• pp.190-197
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• 1992

In this study we have investigated physical and electrical properties of high temperature oxide (HTO) thin film using dichlorosilane (DCS) gas. This film had low etch rate and excellent step coverage, and its characteristics of Si-O bond were similar to those of thermal oxide. I-V curves also showed similar electrical properties to those of thermally grown oxide (SiO2) while time dependent dielectric breakdown (TDDB) results revealed 1/4 value of thermal oxide. However, defect density was measured to be much lower value than that of thermal oxide.

• Corrosion Science and Technology
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• v.14 no.3
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• pp.140-146
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• 2015

The commercialization of aluminum had been delayed than other metals because of its high oxygen affinity. Anodizing is a process in which oxide film is formed on the surface of a valve metal in an electrolyte solution by anodic oxidation reaction. Aluminum has thin oxide film on surface but the oxide film is inhomogeneous having a thickness only in the range of several nanometers. Anodizing process increases the thickness of the oxide film significantly. In this study, porous type oxide film was produced on the surface of aluminum in sulfuric acid as a function of electrolyte temperature, and the optimum condition were determined for anodizing film to exhibit excellent cavitation resistance in seawater environment. The result revealed that the oxide film formed at $10^{\circ}C$ represented the highest cavitation resistance, while the oxide film formed at $15^{\circ}C$ showed the lowest resistance to cavitation in spite of its high hardness.

• Electrical & Electronic Materials
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• v.7 no.2
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• pp.145-151
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• 1994

The multi-dielectric layer SiOz/Si3N4/SiO2(ONO) is used to scale down the memory device. In this paper, the change of composition in ONO layer due to the process condition and the conduction mechanism are observed. The composition of the oxide film grown through the oxidation of nitride film is analyzed using auger electron spectroscopy(AES). AES results show that oxygen concentration increases at the interface between oxide and nitride layers as the thickness -of the top oxide layer increases. Results of I-V measurement show that the insulating properties improve as the thickness of the top oxide layer increases. But when the thickness of the nitride layer decreases below 63.angs, insulating peoperties of film 28.angs. of top oxide and film 35.angs. turn over showing that insulating property of film 28.angs. of top oxide is better than that of film 35.angs. of top oxide. This phenomenon of turn over is thought as the result of generation of surface state due to oxygen flow into nitride during oxidation process. As the thickness of the top oxide and nitride increases, the electrical breakdown field increases, but when the thickness of top oxide reaches 35.angs, the same phenomenon of turn over occurs. Optimum film thickness for scaled multi-layer dielectric of memory device SONOS is estimated to be 63.angs. of nitride layer and 28.angs. of top oxide layer. In this case, maximum electrical breakdown field and leakage current are 18.5[MV/cm] and $8{\times}{10^-12}$[A], respectively.

• Corrosion Science and Technology
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• v.9 no.1
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• pp.20-28
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• 2010

According to the bipolar model, ion selectivity of some species in the passive film is important factor to control the passivation. An increase of cation selectivity of outer layer of the passive film can stabilize the film and improves the corrosion resistance. Therefore, the formation and roles of ionic species in the passive film should be elucidated. In this work, two types of solution (hydrochloric or sulfuric acid) were used to test high N and Mo-bearing stainless steels. The objective of this work was to investigate the formation of oxyanions in the passive film and the roles of oxyanions in passivation of stainless steel. Nitrogen exists as atomic nitrogen, nitric oxide, nitro-oxyanions (${NO_x}^-$), and N-H species, not nitride in the passive film. Because of its high mobility, the enriched atomic nitrogen can act as a reservoir. The formation of N-H species buffers the film pH and facilitates the formation of oxyanions in the film. ${NO_x}^-$ species improve the cation selectivity of the film, increasing the oxide content and film density. ${NO_x}^-$ acts similar to a strong inhibitor both in the passive film and at active sites. This facilitates the formation of chromium oxide. Also, ${NO_x}^-$ can make more molybdate and nitric oxide by reacting with Mo. The role of Mo addition on the passivation characteristics of stainless steel may differ with the test environment. Mo exists as metallic molybdenum, molybdenum oxide, and molybdate and the latter facilitates the oxide formation. When nitrogen and molybdenum coexist in stainless steel, corrosion resistance in chloride solutions is drastically increased. This synergistic effect of N and Mo in a chloride solution is mainly due to the formation of nitro-oxyanions and molybdate ion. Oxyanions can be formed by a 'solid state reaction' in the passive film, resulting in the formation of more molybdate and nitric oxide. These oxyanions improve the cation selectivity of the outer layer and form more oxide and increase the amount of chromium oxide and the ratio of $Cr_2O_3/Cr(OH)_3$ and make the film stable and dense.

• Journal of the Korean institute of surface engineering
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• v.55 no.2
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• pp.63-69
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• 2022

Preparing various types of thin films of oxide semiconductors is a promising approach to fabricate efficient photoanodes and photocathodes for hydrogen production via photoelectrochemical (PEC) water splitting. In this work, we investigate the feasibility of an efficient photocathode for PEC water reduction of a p-type oxide semiconductor cupric oxide (CuO) thin film prepared via a facile method combined with sputtering Cu metallic film on fluorine-doped thin oxide (FTO) coated glass substrate and subsequent thermal oxidation of the sputtered Cu metallic film in dry air. Characterization of the structural, optical, and PEC properties of the CuO thin film prepared at various Cu sputtering powers reveals that we can obtain an optimum CuO thin film as an efficient PEC photocathode at a Cu sputtering power of 60 W. The photocurrent density and the optimal photocurrent conversion efficiency for the optimum CuO thin film photocathode are found to be -0.3 mA/cm² and 0.09% at 0.35 V vs. RHE, respectively. These results provide a promising route to fabricating earth-abundant copper-oxide-based photoelectrode for sunlight-driven hydrogen generation using a facile method.

• Journal of Electrochemical Science and Technology
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• v.4 no.4
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• pp.163-170
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• 2013

Tantalum anodic oxide film was prepared in citric acid solution of various concentrations and the prepared Ta anodic oxide film was characterized by various electrochemical techniques and X-ray photoelectron spectroscopy (XPS). The prepared Ta anodic oxide film showed typical n-type semiconducting properties and the dielectric properties were strongly dependent on the citric acid concentration. The variation of electrochemical and electronic properties was explained in terms of electrolyte anion incorporation into the anodic oxide film, which was supported by XPS measurements.

• Corrosion Science and Technology
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• v.21 no.4
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• pp.282-289
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• 2022

Aluminum 1000 series alloy, a pure aluminum with excellent workability and weldability, is mainly used in the ship field. Aluminum alloy can combine with oxygen in the atmosphere and form a natural oxide film with high corrosion resistance. However, its corrosion resistance and durability are decreased when it is exposed to a harsh environment for a long period of time. For solving this problem, a porous oxide film can be formed on the surface using an anodizing treatment method, a typical surface technique among various methods. In this study, aluminum 1050 alloy was anodized for 2 minutes, 6 minutes, and 10 minutes. The structure and shape of the oxide film were then analyzed to determine the corrosion resistance according to the thickness of the oxide film that changed depending on working condition using 15 wt% NaCl. After it was immersed in NaCl solution for 1, 5, and 10 days, corrosion damage was observed. Results confirmed that the thickness of the oxide film increased as the anodization time became longer. The depth of surface damage due to corrosion became deeper when the film was immersed in the 15 wt% NaCl solution for a longer period of time.

• Journal of the Korean Ceramic Society
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• v.13 no.2
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• pp.8-16
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• 1976

The conductive transparent film is prepared by spraying thin salt solution. In stannic chloride solution as a base solution, various dopants such as Al, Co, Cu and Ni were dissolved respectively as a chloride state and then the films were made by spraying solutions on hot glass plates. The properties of them were compared with those of the stannic salt single component film. The films doped with copper oxide and nickle oxide were improved by decreasing their sheet resistivity and temperature coefficient of resistivity. In comparison with the sheet resistivity and temperature coefficient of resistivity of stannic oxide single component film, being 2.5 K ohm/$\textrm{cm}^2$ and -1650ppm/$^{\circ}C$ respectively, its values of the film containing 15 mol % of copper oxide and formed at 40$0^{\circ}C$ were 2.5K ohm/$\textrm{cm}^2$ and -920ppm/$^{\circ}C$ respectively. The film containing 15 mol % of nickel oxide and formed at 50$0^{\circ}C$ has shown its sheet resistivity and temperature coefficient 0.7 K ohm/$\textrm{cm}^2$ and -940ppm/$^{\circ}C$ respectively.