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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Korean Crystal Growth and Crystal Technology
Journal Basic Information
Journal DOI :
The Korea Association of Crystal Growth
Editor in Chief :
Volume & Issues
Volume 6, Issue 4 - Nov 1996
Volume 6, Issue 3 - Aug 1996
Volume 6, Issue 2 - May 1996
Volume 6, Issue 1 - Mar 1996
Selecting the target year
single crystal growth by the continuous growth method (Orrms method) : (I) On the growth process
Journal of the Korean Crystal Growth and Crystal Technology, volume 6, issue 3, 1996, Pages 293~300
A continuous growth method (Orr's method) were developed to grow LiNbO3 single crystals. The optimum growth condition established are as follows; When the controlled temperature of a platinum crucible were 1190℃∼1210℃, the pulling rate was 2 mm/hr, the feeding rate was 1.5∼2.5 g/hr, and the rotation speed was 20 rpm. The phase and growth orientation of the grown LiNbO3 crystals wer characterized by a X-ray diffraction method. The overflowing phenomena, which induced cracking into the grown crystal during the process, was effectively suppressed by the control of the growth parameter.
single crystals growth by the continuous growth method (Orrms method) : (II) On the domain structure
Journal of the Korean Crystal Growth and Crystal Technology, volume 6, issue 3, 1996, Pages 301~308
Domain structure and properties of LiNbO3 single crystals grown by continuous method (Orr's method) were characterized. It was found that the growth striation of the grown crystals correspond with domain structure and the positive-negative domains were repeated with the perpendicular direction to the C axes. The formation of negative domains were related to the rapid crystal growth rate. The measured dielectric constant of the grown crystal was 140∼150 at 100 kHz at the room temperature and Curie point was 1153℃.
Deposition properties of
thin films by LP-MOCVD
Journal of the Korean Crystal Growth and Crystal Technology, volume 6, issue 3, 1996, Pages 309~317
Al2O3 thin films were deposited on Si-wafer (100) using organo-aluminum compounds at low pressure by chemical vapor deposition (CVD) method. The vapor of the organo-metallic precursor was carried by pure N2 gas. The deposition rate increased and then saturated as Tsub increased with increasing the AIP flow rate. The main contamination didn't found in deposited films except carbon. The H-O(H2O) IR absorption band decreased in intensity as the deposition temperature increased, and completely disappeared through annealing.
A study on copper thin film growth by chemical vapor deposition onto silicon substrates
Journal of the Korean Crystal Growth and Crystal Technology, volume 6, issue 3, 1996, Pages 318~326
This study is to investigate a chemical vapor deposition technique of copper film which is expected to be more useful as metallizations of microcircuit fabrication. An experimental equipment was designed and set-up for this study, and a Cu-precursor used that is a metal-organic compound, named (hfac)Cu(I)VTMS ; (hevaflouoroacetylacetonate trimethyvinylsilane copper). Base pressure of the experimental system is in
Torr, and the chamber pressure and the substrate temperature can be controlled in the system. Before the deposition of copper thin film, tungsten or titanium nitride film was deposited onto the silicon wafer. Helium has been used as carrier gas to control the deposition rate. As a result, deposition rate was measured as
which is higher than the results of previous studies, and the average surface roughness was measured as about
. A deposition selectivity was observed between W or TiN and
, and optimum results are observed at
of substrate temperature and 0.8 Torr of chamber pressure.
A study of defect structures in
single crystals by optical absorptions
Journal of the Korean Crystal Growth and Crystal Technology, volume 6, issue 3, 1996, Pages 327~340
In this study, a series of
crystals with different [Li]/[Nb] ratios, congruent
crystals with doped Mg and with Mg and codoped with Mn were grown by the Czocharalski method. These were investigated by UV and IR spectrophotometry. Stoichiometry dependences of the UV absorption edge and the
absorption spectra were studied with different [Li]/[Nb] ratios. The position of the UV absorption edge adn the shape and peak point of the
absorption spectra changed monotonously upto a critical concentration of Mg ions. The mechanism of the incorporation of Mg ions changes at this concentration. The decomposition of the
absorption spectra using a Gaussian lineshape function showed that in Li-deficient crystals the absorption spectra consist of five components in contrast to more or less perfect stoichiometric crystals which reveal to three components. On the basis of these results, the intrinsic and the extrinsic defect structure models in
crystals were examined. The behaviour of
(OH) reflects the defect structure and supports the Li-site vacancy model as the intrinsic defect structure model and the corresponding extrinsic defect model. A brief discussion is also given of the behaviour of
crystals simultaneously doped with several kinds of impurity.
Growth of CdS thin film using hot wall epitaxy method and their photoconductive characteristics
Journal of the Korean Crystal Growth and Crystal Technology, volume 6, issue 3, 1996, Pages 341~350
The CdS thin films are grown on quartz plate by hot wall epitaxy. The source and substrate temperature is
respectively, and thickness of the film is
. Using extrapolation method of X-ray diffraction patterns for the CdS thin film, it was found hexagonal structure whose lattice constant a and c were
, respectively. Hall effect on this sample was measured by the method of van der Pauw and studied on cattirer density and mobility depending on temperature. From hall data, the mobility was likely to be decreased by piezoelectric scattering in the temperature range 30 K to 200 K and by polar optical scattering in the temperature range 200 K to 293 K. In order to explore the applicability as a photoconductive cell we measured the sensitivity (
), the ratio of photocurrent to darkcurrent (pc/dc), maximum allowable power dissipation (MAPD), spectral response and response time. The results indicated that for the samples annealed in Cu vapor the photoconductive characteristics are the best. Then we obtained the sensitivity of 0.99, the value of pc/dc of
, the MAPD of 318 mW, and the rise and decay time of 10 ms and 9 ms, respectively.
Effects of hydrogen plasma on the formation of self-organized InAs-quantum dot structure
;;;K. Ozasa;Y. Aoyagi;
Journal of the Korean Crystal Growth and Crystal Technology, volume 6, issue 3, 1996, Pages 351~359
We have investigated the effect of hydrogen plasma on the formation of InAs QDs (quantum dots) structure by using a CBE (chemical beam epitaxy)system equipped with ECR (electron cyclotron resonance) plasma source. It is confirmed that the formation of self-organized InAs-QDs on GaAs is started after the growth of InAs layer up to 2.6 ML (monolayer) with the irradiation of hydrogen plasma while it is started after 1.9 ML without hydrogen gas and hydrogen plasma through the observation of RHEED patterns. Density and size of the QDs formed at
and 17.7 nm without hydrogen plasma, and
and 19.4 nm with hydrogen plasma, respectively. It is also observed from the PL(photoluminescence) measurement on InAs-QDs that red shift in PL peak energy and broadening in FWHM (full width at half maximum)of PL peak caused by the effects of hydrogen plasma on the increment of size and its distribution. These effects of hydrogen plasma are considered as a act of atomic hydrogen which enhances the layer-growth of InAs on GaAs resulted from the relief of misfit strain between GaAs substrate and InAs.
The effect of cooling rate on the nuclei of OISF formation in Si single crystals
Journal of the Korean Crystal Growth and Crystal Technology, volume 6, issue 3, 1996, Pages 360~367
The OISF (Oxidation Induced Stacking Fault)is expected to affect the electrical properties in Si single crystals, and the nuclei of OISF are believed to be formed during the crystal growing process. Initial oxygen concentration, dopant type and its density, and cooling rate are regareded as major factors on OISF formation. In this study, the variations of OISF density under various cooling rate were investigated. Si single crystal was heated to
in Ar ambient and cooled down to room temperature at different cooling rate, using horizontal tube furnace. After that, they were oxidized at
, and then, OISF was observed with optical microscope. The relation between oxide procipitates and OISF nucleation was investigated by FTIR analysis. As a result, it was found that there exists the intermediate cooling rate range in which OISF nucleation is highly enhanced. And also, it was found that OISF nucleation is closely related with silicon oxide procipitation in Si single crystals.
Single crystals growth and properties of
doped with MgO or ZnO : (I) Single crystals growth and their defect structure
Journal of the Korean Crystal Growth and Crystal Technology, volume 6, issue 3, 1996, Pages 368~376
single crystals (undoped, 5 mol% MgO-doped and 5 mol% ZnO-doped) were grown by the floating zone method which has the characteristics of a compositional homogeneity and uniform distribution of the dopants. The optimum growth condition was established experimentally and the defect structures such as domain structure, dislocation structure, slip band, and microtwins were characterized using a microscopic method.
X-ray diffraction analysis of ZnS/ZnSe superlattices prepared by hot wall epitaxy
Yong Dae Choi ; A. Ishida ; Fujiyasu, H. ;
Journal of the Korean Crystal Growth and Crystal Technology, volume 6, issue 3, 1996, Pages 377~385
ZnS/ZnSe superlattices were prepared on GaAs (100) substrates by hot wall epitaxy, an the structures were analyzed using x-ray diffraction. It is shown that the x-ray diffraction of the strained superlattice gives very useful information about the thickness of each layer, strain, interdiffusion, and the fluctuation of the superlattice period. Interdiffusion length of the S and Se is estimated to be less than
Effect of SiC volume fraction on mechanical properties and microstructure of
Journal of the Korean Crystal Growth and Crystal Technology, volume 6, issue 3, 1996, Pages 386~391
SiC particles (average size is 270 nm) of 0, 10, 20, 30, 40 vol% were dispersed in
nanocomposites were fabricated by hot press. After sintering, matrix phase,
was transformed to
, and second phase,
was not changed. No grain boundary crystalline phase by adding of sintering additives was detected. Grain growth of
was supressed with increasing of SiC contents, and then fine grain was occurred. The highest fracture strength was obtained at 10 vol% SiC, and fracture toughness was decreased, but hardness was linearly increased with SiC content.
Effect of SiC mean particle size on mechanical properties and microstructure of
Journal of the Korean Crystal Growth and Crystal Technology, volume 6, issue 3, 1996, Pages 392~398
nanocomposites reinforced with tow different mean particle size were fabricated by hot press. Grain growth of matrix gran was inhibited by adding of SiC particles, and then number of equiaxed and fine grains were increased. The effect of grain growth inhibition was higher in the nanocomposites dispersed small size SiC. herefore fracture strength and hardness were increased, but fracture toughness was decreased in small size SiC dispersed samples.
Present status of buried contact solar cell research in Samsung advanced institute of technology (SAIT)
A.U. Ebong ; S.H. Lee ; D.S. Kim ; Y.H. Cho ; C.E. Cho ;
Journal of the Korean Crystal Growth and Crystal Technology, volume 6, issue 3, 1996, Pages 399~405
The present buried contact (BC) solar cell research at SAIT includes the development of a processing sequence suitable for production of the single sided (SS) BC solar cells. This paper presents some results for large area (
) SSBC cells fabricated on FZ and CZ silicon substrates. Cell efficiencies in excess of 18% fabricated on FZ, p-type, 0.5 ohm-cm, and over 16% on CZ p-type, 10~20 ohm-cm, wafers have been demonstrated. Both the FZ and CZ wafers were chemically textured. These results are preliminary and the exploration of double sided (DS) sequence, which is the future BC structure would lead to over 17% and 20% efficiency cells on CZ and FZ substrates respectively. The cost of solar cells can be reduced further if the many high temperature steps can be reduced to only one. This would be very advantageous to very poor quality substrates such as the CZ grown wafers.
Effects of changing the oxygen partial pressure in cooling after deposition of PZT thin films by reactive sputtering
Journal of the Korean Crystal Growth and Crystal Technology, volume 6, issue 3, 1996, Pages 406~414
We studied the phase formation and the effect of electrical properties of PZT thin films with changing the oxygen partial pressure in cooling after deposition of PZT thin film by reactive sputtering method. The roughness of thin film increased with decreasing the oxygen partial pressure in cooling due to the evaporation on the surface ofthin films and the grain size was not changed very much. The hysteresis property of PZT thin film was improved toward having a good squareness with increasing the cooling oxygen partial pressure. We observed the decrease of remanent polarization, retained polarization and coercive field with decreasing the oxygen partial pressure. Dielectric constant decreased gradually and internal bias field increased in the measurement of dielectric constant-voltage property with decreasing cooling oxygen partial pressure. We observed the increase of nonswitched polarization in the measurement of field accelerated retention and the decrease of nonswitched polarization with increasing the bias time.
Formation of Ni layer onto alumina powders by hydrogen reduction technique
Journal of the Korean Crystal Growth and Crystal Technology, volume 6, issue 3, 1996, Pages 415~423
Hydrogen reduction technique was used to form the nickel layer onto alumina powders in nickel sulfate solutions. The reduction rate and precipitation states of nickel ions were investigated at various experimental conditions such as hydrogen pressure, temperature,
addition, particle size, and so on. Uniformly nickel coated alumina composite powders were obtained at such condition as reduction temperature of
, hydrogen pressure of 300 psi, and
Diffusion of buried contact grooves with spin-on source
A.U. Ebong ; S.H. Lee ;
Journal of the Korean Crystal Growth and Crystal Technology, volume 6, issue 3, 1996, Pages 424~430
The present processing sequence for solar cells is very elaborate and ads to the cost of the fabricated cells. This processing cost, which accounts for about 30% of the total cost, can be reduced if the many high temperature sequences can be reduced without significantly reducing the cells energy conversion efficiency. By using the spin-on glasses (SOG) in conjunction with the conventional tube furnace (CTF) or rapid thermal annealer (RTA), the many high temperature process can be reduced to only one. In order to achieve efficiencies similar to the standard high temperature sequences using the solid or liquid sources, some basic characterization of the groove diffusion is necessary to ascertain the its suitability. This paper describes the work done in diffusing the buried contact grooves using the phosphorus SOG.
Fe-rich precipitates in hot-pressed
Kwang Bo Shim ; Keun Ho Auh ; Brian Ralph ;
Journal of the Korean Crystal Growth and Crystal Technology, volume 6, issue 3, 1996, Pages 431~438
Transmission electron microscopy has been used to investigate the microstructure of hot-pressed
. Thin foil specimens, prepared by conventional ion beam thinning, revealed many features which originated from the crystallographic anisotropy of hexagonal
. It was observed that in these specimens Fe-impurities are precipitated to form secondary Fe-rich phases at grain triple edges, in grain boundaries and sometimes in-grain. These Fe-rich precipitates were characterised by their coherence or semi-coherence to a favourably oriented grain at a grain triple edge or grain boundaries or to the matrix
Study on the temperature and optical wavelength sensing composites as smart materials
;Delbert E. Day;James O. Stoffer;
Journal of the Korean Crystal Growth and Crystal Technology, volume 6, issue 3, 1996, Pages 439~448
The possibility of application or the transparent BK10 glass fiber/PMMA composites as a temperature-or wavelength-sensors was studied. Measurement of diameter and refractive index for glass fibers to be reinforced to PMMA as a function of drawing speed and temperature was done and the appropriate coating methods and solvent for coupling agent was researched.
value at which the maximum transmission for the composites occurs could be controlled to be in
by the processing factors such as fiber diameter, fiber vol%, molecular wt. of PMMA. Furthermore, with different wavelength other than 589.3 nm, the
value could be controlled to be in
. For the sensibility of wavelength for the composites, there was not a wavelength (
) showing maximum transmission.
Effects of operating conditions on the crystallization of lanthanum oxalate in semi-batch reactor
Journal of the Korean Crystal Growth and Crystal Technology, volume 6, issue 3, 1996, Pages 449~462
On the reaction crystallization of lanthanum oxalate effects of operation conditions of impeller speed, concentration and feed rate of reactant, and reaction temperature on the nucleation and growth of crystals were investigated experimentally. In general, at low supersation the analysis of crystallization processes is relatively clear. However, at high wupersaturation, which is usually applied in industrial crystallization, the processes are exhibited in much complication. In this study the lanthanum oxalate was crystallized by the reaction crystallization of high concentration of lanthanum chloride and oxalic acid in single-jet semi batch reactor. Agitation of solution and suspension in the reactor influenced to enhance the reaction process and crystal growth process which gave opposite effect on the crystallization of lanthanum oxalate. In our experiment since increase of impeller speed gave more influence on the reaction process rather than on the crystal growth process, the supersaturation concentration increased with increase of impeller speed, then resulted in decrease of mean crystal size. By the same effect of reactant concentration and feed rate, the decrease of mean crystall size of lanthanum oxalate was observed with increasing the reactant concentration and feed rate. In case of increasing reaction temperature, the mean crystal size increased. The morphology of lanthanum oxalate crystal was not changed within the variation ranges of the operation conditions which were applied in our experiment.
Fabrication and microstructure of the Fe doped
composite membranes with ultrafine pores
Dong-Sik Bae ; Kyong-Sop Han ; Sang-Hael Choi ;
Journal of the Korean Crystal Growth and Crystal Technology, volume 6, issue 3, 1996, Pages 463~470
Ceramic membrane consisting of an
support and Fe doped
top layer was prepared by the sol-gel method. The supported Fe doped
top layer was made by dip coating the support in a mixed sol. The microstructure of the composite membranes was studied by SEM after calcination at
. After sintering at
for 1 hr., the average particle diameter of the Fe doped
top layer was ~40 nm. The supported Fe doped
composite membranes exhibited much higher heat resistance than the
membrane. The Fe doped
composite membrane retained a crack-free microstructure and narrow particle size distribution even after calcination up to