• Journal of the Korean earth science society
• /
• v.25 no.1
• /
• pp.48-51
• /
• 2004

The light element candidates such as S, O, Si, and K are discussed for the reasonable compositions in the earth's core since the available data show density difference from pure iron core. These candidates are favored by the some evidences such as depletion in the crust and mantle, and lower eutectic temperature of Fe-FeS melt for sulfur. FeO phase for oxygen, lighter mass than sulfur and solubility in metallic phases for silicon, and partitioning in Fe-FeS melt for potassium. However, other problems such as short experimental data, initial compositions of these elements, and oxidation state during the formation of the earth should be solved simultaneously to confirm these light elements.

• Proceedings of the KIEE Conference
• /
• 1987.07a
• /
• pp.436-438
• /
• 1987

The thermal oxidation recipe has been optimized for very thin (12 nm) capacitor oxide for Mega bit DRAM. The time dependent dielectric breakdown characteristics show that the breakdown voltage and time to breakdown are very high and uniform, indication that our oxide is defect free and suitable for DRAM capacitor dielectric. To our knowledge this is the best oxide quality obtained up tp now around 10 nm.

• Proceedings of the KIEE Conference
• /
• 1987.07a
• /
• pp.416-419
• /
• 1987

The miniaturization of Bird's Beak generated at the field oxidation has been studied by adding polysilicon layer between the silicon nitride and pad oxide stack, which is the basic structure of Conventional LOCOS. The size and shape of Bird's Beak were intensively observed by SEM, and also the electrical characteristics of Bird's Beak-reduced LOCOS structure were compared with those of Conventional LOCOS. The length of Bird's Beak was reached up to $0.20-0.28{\mu}m$, while about to $0.50-0.53{\mu}m$ in conventional LOCOS, resulting in 60% reduction.

• Journal of the Korean institute of surface engineering
• /
• v.29 no.5
• /
• pp.407-414
• /
• 1996

We have investigated the effects of H atoms on thin film growth processes and surface reactions. In the oxidation of Si, Si surfaces are passivated against the $O_2$ adsorption by terminating dangling bonds with H atoms. Moreover, the existence of Si-H bonds on Si(100) surfaces enhances the structural relaxation of Si-O-Si bonds due to a charge transfer from Si-Si back bonds. In the heteroepitaxial growth of a Si/Ge/Si(100) system, H atoms suppress the segregation of Ge atoms into Si overlayers since the exchange of Ge atoms with Si atoms bound with H must be accompanied with breaking of Si-H bonds. However, 3-dimensional island growth is also promoted by atomic H irradiation, which is considered to result from the suppression of surface migration of adsorbed reaction species and from the lowering of step energies by the H termination of dangling bonds.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.10a
• /
• pp.330-333
• /
• 2005

The fabrication of mold fur nano imprint lithography (NIL) is experimentally reported using the scanning probe lithography (SPL) technique, instead of the conventional I-beam lithography technique. The nanometer scale patterning structure is fabricated by the localized generation of oxide patterning on the silicon (100) wafer surface with a thin oxide layer, The fabrication method is based on the contact mode of scanning probe microscope (SPM) in air, The precision cleaning process is also performed to reach the low roughness value of $R_{rms}=0.084 nm$, which is important to increase the reproducibility of patterning. The height and width of the oxide dot are generated to be 15.667 nm and 209.5 nm, respectively, by applying 17 V during 350 ms.

• Journal of Conservation Science
• /
• v.38 no.4
• /
• pp.327-333
• /
• 2022

Sri Lanka has four types of mural painting styles; Classic, Late Classic, Kandyan, and Southern styles, but there is little research on scientific analysis for mural paintings. In this study, we analyze white, yellow, and red clay pigments which were collected from ancient producing sites. Analyzing pigment samples shows that samples are containing aluminum oxide(Al₂O₃) and silicon dioxide(SiO₂) which are connected to the soil. And a degree of iron oxidation determines yellow or red colors. To understand the characteristics of clay pigment samples, we go over previous pigment analyses of mural paintings in Sri Lanka. Kaolin is identified after the 17^th century, yellow and red ochre are applied in early periods, Classic and Late Classic styles. The change in raw materials of pigments occurred in the 17^th century.

• Journal of the Microelectronics and Packaging Society
• /
• v.19 no.1
• /
• pp.55-60
• /
• 2012

In order to develop electroless-plated Nickel Phosphate (Ni-P) as a contact material for high efficient low-cost silicon solar cells, we evaluated the effect of ambient thermal annealing on the degradation behavior of interfacial adhesion energy between electroless-plated Ni-P and silicon solar cell wafers by applying 4-point bending test method. Measured interfacial adhesion energies decreased from 14.83 to 10.83 J/$m^2$ after annealing at 300 and $600^{\circ}C$, respectively. The X-ray photoelectron spectroscopy analysis suggested that the bonding interface was degraded by environmental residual oxygen, in which the oxidation inhibit the stable formation of Ni silicide phase between electroless-plated Ni-P and silicon interface.

• The Journal of Natural Sciences
• /
• v.8 no.2
• /
• pp.137-146
• /
• 1996

To increase the oxidation-resistance of graphite substrate, we have tried to form SiC film on its surface by Sol-Gel method. TEOS(Tetraethyl orthosilicate) and phenol resin have been used as silicon(Si) and carbon(C) sources, respectively. In order to know the effect of the TEOS Sol concentration on the forming of SiC film, we have taken 5 different $H_2O$/TEOS mol ratios of 2, 4, 6, 8 and 10. And the coating states of SiC on the graphite substrate have been analyzed with X-ray diffractometer and scanning electron microscope (SEM), and we have obtained about 5${\mu}m$, 12${\mu}m$, 7${\mu}m$, 7${\mu}m$ and 2 ${\mu}m$ as the thickness of SiC coating layers, respectively. For also knowing the oxidation resistance the SiC coated graphites at $1600^{\circ}C$ were heated again at $1000^{\circ}C$ under air atmosphere for 1 hr, and as a result we have received the weight losses of 26.17%, 20.97%, 17.28%, 21.73% and 28.13%, respectively.

• Journal of Sensor Science and Technology
• /
• v.4 no.3
• /
• pp.51-59
• /
• 1995

Stress-balanced flat 150 nm-$Si_{3}N_{4}$/300 nm-$SiO_{2}$/150 nm-$Si_{3}N_{4}$ dielectric membrane on silicon substrate has been fabricated. Analyses of stress-deflection and stress-temperature, and visual inspection for the strain diagnostic test patterns were performed in order to characterize stress properties of the membrane. The $SiO_{2}$ layers sandwiched between two $Si_{3}N_{4}$ layers were deposited by three different techniques(PECVD, LPCVD, and APCVD) for the purpose of investigating the dependence of stress on the deposition methods. Some extent of tensile stress in the membrane was always observed regardless of the deposition methods, however it could be balanced against silicon substrate by post-wet oxidation in $1,150^{\circ}C$. Stress-temperature characteristics of the membranes showed that APCVD-LTO was better as mid-$SiO_{2}$ layer than PECVD - or LPCVD - $SiO_{2}$ when there was no oxidation process.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.308-309
• /
• 2016

Reducing surface recombination is a critical factor for high efficiency silicon solar cells. The passivation process is for reducing dangling bonds which are carrier. Tunnel oxide layer is one of main issues to achieve a good passivation between silicon wafer and emitter layer. Many research use wet-chemical oxidation or thermally grown which the highest conversion efficiencies have been reported so far. In this study, we deposit ultra-thin tunnel oxide layer by PECVD (Plasma Enhanced Chemical Vapor Deposition) using $N_2O$ plasma. Both side deposit tunnel oxide layer in different RF-power and phosphorus doped a-Si:H layer. After deposit, samples are annealed at $850^{\circ}C$ for 1 hour in $N_2$ gas atmosphere. After annealing, samples are measured lifetime and implied Voc (iVoc) by QSSPC (Quasi-Steady-State Photo Conductance). After measure, samples are annealed at $400^{\circ}C$ for 30 minute in $Ar/H_2$ gas atmosphere and then measure again lifetime and implied VOC. The lifetime is increase after all process also implied VOC. The highest results are lifetime $762{\mu}s$, implied Voc 733 mV at RF-power 200 W. The results of C-V measurement shows that Dit is increase when RF-power increase. Using this optimized tunnel oxide layer is attributed to increase iVoc. As a consequence, the cell efficiency is increased such as tunnel mechanism based solar cell application.