• Korean Journal of Crystallography
• /
• v.3 no.2
• /
• pp.98-110
• /
• 1992

B-SiC thin films were fabricated on Si(100) substrate under 1 atom by fVD. The effects of deposition conditions on the growth and the properties especially crystallinity and prefer ential alignment of these thin films were investigated. SiH4 and CH4 were used as source gases and H2 as Carrier gas. Th9 growth Of B-SiC thin films with changing parameters such as the growth temperature, the ratio of source gases (SiH4/CH4 ) and the total amount of source gases. The grown thin films were characterized by using SEM, a -step, XRD, Raman Spectro- scopy and TEM. Chemical conversion process improved the quality of thin films due to the formation of SiC buffer layer. The crystallinity of SiC thin films was improved when the growth temperature was higher than l150t and the amount of CH4 exceeded that of SiH4. The better crystallinity, the better alignment to the crystalline direction of substates. TEM analyses of the good quality thin films showed that the grain size was bigger at the surface than at the interface and the defect density is not depend on the ratio of the source gases.

• Proceedings of the KIEE Conference
• /
• 2003.07c
• /
• pp.1490-1492
• /
• 2003

A new type of piezoelectric transformer using radial vibration of disk, poled with the same direction is proposed. The piezoelectric ceramics was composed to PZT-PMN-PSN. The surface ratio of driving electrode and generating electrode of the piezoelectric transformer ranges from 1.4:1 to 3:1. As a experimental result, both resonance frequency and step-up voltage ratio increased with increasing load resistance. The step-up voltage ratio was reached more than 60 times under no load resistance. The maximum efficiency of 97.7% at load resistance of 2k${\Omega}$ was obtained.

• Journal of the Korean Ceramic Society
• /
• v.38 no.12
• /
• pp.1150-1154
• /
• 2001

Silicon oxynitride (SiON) thick films using the core layer of silica optical waveguide have been deposited on Si wafer by PECVD at low temperature (32$0^{\circ}C$) were obtained by decomposition of appropriate mixture of (SiH$_4$+$N_2$O+$N_2$) gaseous mixtures under RF power and SiH$_4$/($N_2$O+$N_2$) ratio deposition condition. Prism coupler measurements show that the refractive indices of SiON layers range from 1.4663 to 1.5496. A high SiH$_4$/($N_2$O+$N_2$) of 0.33 and deposition power of 150 W leads to deposition rates of up to 8.67 ${\mu}{\textrm}{m}$/h. With decreasing SiH$_4$/($N_2$O+$N_2$) ratio, the SiON layer become smooth from 41$\AA$ to 6$\AA$.

• 한국초전도학회:학술대회논문집
• /
• v.13
• /
• pp.72-72
• /
• 2003

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.21 no.9
• /
• pp.848-852
• /
• 2008

Characteristics of microcrystalline-silicon thin-films deposited by plasma-enhanced chemical-vapor deposition (PECVD) method were studied. There were optimum values of RF power density and $H_2$ dilution ratio $(H_2/(SiH_4+H_2))$; maximum grain size of about 35 nm was obtained at substrate temperature of 250 $^{\circ}C$ with RF power density of 1.1 W/$cm^2$ and $H_2$ dilution ratio of 0.91. Larger grain was obtained with higher substrate temperature up to 350 $^{\circ}C$. Grain size dependence on RF power density and $H_2$ dilution ratio could be explained by etching effects of hydrogen ions and changes of species of reactive precursors on growing surface. Surface-mobility activation of reactive precursors by temperature could be a reason of grain-size dependence on the substrate temperature. Microcrystalline-silicon thin-films that could be used for flat-panel electronics such as active-matrix organic-light-emitting-diodes are expected to be fabricated successfully using these results.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2010.05a
• /
• pp.655-656
• /
• 2010

• Korean Journal of Materials Research
• /
• v.11 no.6
• /
• pp.527-532
• /
• 2001

Dry etching of copper film using $O_2$ plasma and H(hfac) has been investigated. A one-step process consisting of copper film oxidation with an $O_2$ plasma and the removal of surface copper oxide by the reaction with H(hfac) to form volatile Cu(hfac)$_2$ and $H_2O$ was carried but. The etching rate of Cu in the range from 50 to 700 /min was obtained depending on the substrate temperature, the H(hfac)/O$_2$ flow rate ratio, and the plasma power. The copper film etch rate increased with increasing RF power at the temperatures higher than 215$^{\circ}C$. The optimum H(hfac)/O$_2$ flow rate ratio was 1:1, suggesting that the oxidation process and the reaction with H(hfac) should be in balance. Cu patterning using a Ti mask was performed at a flow rate ratio of 1:1 on 25$0^{\circ}C$\ulcorner and an isotropic etching profile with a taper slope of 30$^{\circ}$was obtained. Cu dry patterning with a tapered angle which is necessary for the advanced high resolution large area thin film transistor liquid-crystal displays was thus successfully obtained from one step process by manipulating the substrate temperature, RF power, and flow rate ratio.

• 한국생물공학회:학술대회논문집
• /
• 2001.11a
• /
• pp.363-366
• /
• 2001

This study was to investigate the effects of media components on the mycelial growth of Lentinus eclodes, including C-source. N-source, Inorganic salts, and c/N ratio. Glucose and yeast extract were selected as C-source and N-source, respectively. $KH_2PO_4,\;K_2HPO_4,\;MGSO_4,\;7H_2O$ as inorganic salts were added. When glucose concentration was 30g/L and yeast extract concentration was 20g/L, indicating that C/N ratio was 1.5, the cell mass was about 9g/L.

• Journal of the Korean Ceramic Society
• /
• v.34 no.3
• /
• pp.249-256
• /
• 1997

The effect of process parameter of plasma assisted chemical vapor deposition (PACVD) on the variation of the ratio between cubic boron nitride (c-BN) and hexagonal boron nitride (h-BN) in the film was in-vestigated. The plasma was generated by electric power with the frequency between 100 and 500 KHz. BCl3 and NH3 were used as a boron and nitrogen source respectively and Ar and hydrogen were added as a car-rier gas. Films were composed of h-BN and c-BN and its ratio varied with the magnitude of process parameters, voltage of the electric power, substrate bias voltage, reaction pressure, gas composition, sub-strate temperature. TEM observation showed that h-BN phase was amorphous while crystalline c-BN par-ticle was imbedded in h-BN matrix in the case of c-BN and h-BN mixed film.

• Applied Biological Chemistry
• /
• v.35 no.6
• /
• pp.501-506
• /
• 1992

Pepsin-catalyzed hydrolysis and plastein reaction were carried out to prepare plastein product from soymilk residue protein. Conditions required for optimal hydrolysis of soymilk residue protein and subsequent plastein production were investigated. The optimum substrate concentration, enzyme-substrate ratio, pH, reaction temperature and incubation time for hydrolysis were 3%, 1/50, 1.7, $45^{\circ}C$ and 24 hours, respectively. Plastein formation from peptic hydrolysate of soymilk residue protein was most effective at substrate concentratin of 40%, pH 4 and $45^{\circ}C$. Reaction time of 18 hours and enzyme-substrate ratio of 1/100 were selected for plastein production. Electrophoresis of the products revealed that protein-like substances of high molecular weight were produced from the plastein reaction.