• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.7
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• pp.567-571
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• 2001

We investigated the structural and electrical properties of Ba(Zr$_{x}$Ti$_{1-x}$ )O$_3$(BZT) thin films with a mole fraction of x=0.2 and a thickness of 150 nm. BZT films were prepared on Pt/SiO$_2$/Si substrate with the various substrate temperature by a RF magnetron sputtering system. When the substrate temperature was above 50$0^{\circ}C$, we obtained multi-crystalline BZT films oriented to (110), (111), and (200) directions. As the substrate temperature increases, the films are crystallized and their dielectric constants become high. C-V characteristic curve of the film deposited at high temperature is more sensitive than that of the film deposited at low temperature. The parameters of the BZT film are as follows; the dielectric constants(dissipation factors) at 1 MHz are 95(0.021), 140(0.024), and 240(0.033) deposited at 400, 500, $600^{\circ}C$, respectively; the leakage currents at 666.7 kV/cm are 5.73, 23.5, and 72.8x10$^{-8}$ A/$\textrm{cm}^2$ fo the films deposited at 400, 500, and 600 $^{\circ}C$, respectively; the leakage currents at 666.7kV/cm are 5.73, 23.5, and 72.8x10$^{-8}$ A/$\textrm{cm}^2$ for the films deposited at 400, 500, $600^{\circ}C$, respectively. The BZT film deposited at 40$0^{\circ}C$ shows stable electrical properties, but dielectric constant for application is a little small.ll.

• Korean Journal of Materials Research
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• v.6 no.7
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• pp.723-732
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• 1996

Cu films were deposited by chemical wapor deposition on the as-received substrates (TiN/Si) and three kinds of Cu-seeded substrates (Cu/TiN/Si) which had seeding layer in the thick ness of 5 ${\AA}$ and 130 ${\AA}$ coated by ICB(Ionized Cluster Beam) method. The effect of Cu seeding layers on the growth rate, crystallinity, grain size uniformity and film adhesion strength of final CVD-Cu films was investigated by scanning eletron microscopy(SEM), X-ray diffractometry and scratch test. The growth rate was found to incresase somewhat in the case of ICB-seeding. The XRD patterns of the Cu films on the as-received substrate and ICB Cu-seeded substrates exhibited the diffraction peaks corresponding to FCC phase, but the peak intensity ratio($I_{111}/I_{200}$) of Cu films deposited on the ICB Cu-seeded substrates increased compared with that of Cu films on the as-received substrate. The resistivity of final Cu film on 40 ${\AA}$ seeded substrate was observed as the lowest value, 2.42 $\mu\Omega\cdot$cm compared with other Cu films. In adhesion test, as the seeding thickness increased from zero to 130 ${\AA}$, the adhesion strength increased from 21N to 27N.

• Proceedings of the Korean Vacuum Society Conference
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• 1998.02a
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• pp.87-89
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• 1998

The Y2O3 films on Si(111) was grown by ionized cluster beam depposition (ICBD) in ultrahigh-vacuum (UHV). The acceleration voltage and oxygen ppartial ppressure were fixed at 5 kV and 2$\times$10-5 Torr resppectively. The substrate tempperature was varied from 10$0^{\circ}C$ to $600^{\circ}C$ in order to find the deppendence of crystallinity of Y2O3 films on the substrate tempperature. The crystallinity of the films with the substrate tempperature studied using x-ray diffraction (XRD) and Rutherford backscattering sppectroscoppy (RES). Surface crystallinity and surface morpphology of the films were also investigated using the reflection high-energy electron diffraction (RHEED) and atomic force microscoppe (AFM) resppectively. The films grown at the substrate tempperature below 50$0^{\circ}C$showed the ppoly-crystalline structure of oxygen deficiency. On the contrary the single-crystalline structure was obtained at the substrate tempperature over 50$0^{\circ}C$ and the stochimetry was gradually matched as increasing the substrate tempperature. The surface morpphology showed the increase of the surface roughness as the substrate tempperature was increased upp to 50$0^{\circ}C$ The crystallinity of the film was not good and the minimum channeling yield $\chi$min was measured at 0.91 The stochiometric and high crystallinine film (surface $\chi$min=0.25) was obtained as the substrate tempperature increased upp to 60 $0^{\circ}C$ which indicate the tempperature was sufficient to migrate the depposited atom.

• Proceedings of the KIEE Conference
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• 2001.11a
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• pp.3-5
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• 2001

ZnO thin films are deposited on $SiO_2$/Si (111) substrate by RF magnetron sputtering. The two-step deposition method is proposed to enhance both the c-axis orientation and the resistivity of ZnO films. This method consists of the following two procedures: the 1 st-deposition for 30 min without oxygen at l00W and the 2nd-deposition with oxygen added in the range of $O_2/(Ar+O_2)=10{\sim}50%$. Effects of thermal treatment on the properties of ZnO films are systematically investigated.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.11a
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• pp.71-73
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• 1995

In this work, we synthsized GaN powders by the direct reactions of Ga with NH$_3$at the temperature range of 950∼1150$^{\circ}C$ and we growth the GaN thin films on Si and sapphire substrates using the synthesized GaN powders by the vapor phase epitaxy method. The synthesized powder had hexagonal crystal structures with lattice constants of a$\sub$0/=3.1895${\AA}$, c$\sub$0/=5.18394${\AA}$. The reaction rates of GaN were increased with both reaction time and temperature, however it did not depends on the flow rates of NH$_3$. The island type GaN crystals were grown on (0001) sapphire substrates and fast lateral growth of GaN on (111) Si substrate than sapphire was observed in our experiments.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.39-40
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• 2005

Ferroelectric Eu-substituted $Bi_4Ti_3O_{12}$ (BET) thin films with a thickness of 200 nm were deposited on Pt(111)/Ti/SiO$_2$/Si(100) substrate by means of the liquid delivery MOCVD system and annealed at several temperatures in an oxygen atmosphere. At annealing temperature above $600^{\circ}C$, the microstructure of layered perovskite phase was observed. The remanent polarization of these films increased with increase in annealing temperature. The remanent polarization values ($2P_r$) of the BET thin films annealed at $720^{\circ}C$ were $37.71{\mu}C/cm^2$ at an applied voltage of 5 V.

• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.845-847
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• 1999

(Ba, Sr)$TiO_3$[BST] thin films were fabricated on Pt/$TiO_2/SiO_2$/Si substrate by RF sputtering. The structural and dielectric properties of the BST thin films were investigated with the deposition time. Increasing the deposition time from 20 min. to 60 min., second phases were decreased, and EST (111), (100), (200) peaks were increased. The relative dielectric constant and dielectric loss of the EST thin films with the thickness of 3000$\AA$ were 300 and 0.018, respectively at 1[kHz]. The relative dielectric constants was decreased and dielectric losses was increased as increasing the frequency.

• Journal of the Korean institute of surface engineering
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• v.29 no.5
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• pp.467-473
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• 1996

Heteroepitaxial growth of cubic silicon carbide films on Si(001) and Si(111) substrates at temperatures 900-$1000^{\circ}C$ has been achieved by high vacuum chemical vapor deposition using the single precursor 1, 3-disilabutane without carrying out the carbonization process of the substrate surfaces. The deposition temperature range is much lowered compared with conventiontional chemical vapor deposition where separate sources for silicon and carbon are employed. The deposition procedure is quite simple and safe. The qualities of the films were found to be very good judging from the results obtained by various characterization techniques including reflection high energy electron diffraction, X-ray diffraction, X-ray pole figure analysis, Rutherford backscattering spectrometry, Auger depth profiling, and transmission electron diffraction.

• Transactions on Electrical and Electronic Materials
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• v.6 no.6
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• pp.245-248
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• 2005

The physical and electrical properties of polycrystalline $\beta$-SiC were studied according to different nitrogen doping concentration. Nitrogen-doped SiC films were deposited by LPCVD(1ow pressure chemical vapor deposition) at $900^{\circ}C$ and 2 torr using $100\%\;H_2SiCl_2$ (35 sccm) and $5 \%\;C_2H_2$ in $H_2$(180 sccm) as the Si and C precursors, and $1\%\;NH_3$ in $H_2$(20-100 sccm) as the dopant source gas. The resistivity of SiC films decreased from $1.466{\Omega}{\cdot}cm$ with $NH_3$ of 20 sccm to $0.0358{\Omega}{\cdot}cm$ with 100 sccm. The surface roughness and crystalline structure of $\beta$-SiC did not depend upon the dopant concentration. The average surface roughness for each sample 19-21 nm and the average surface grain size is 165 nm. The peaks of SiC(111), SiC(220), SiC(311) and SiC(222) appeared in polycrystalline $\beta$-SiC films deposited on $Si/SiO_2$ substrate in XRD(X-ray diffraction) analysis. Resistance of nitrogen-doped SiC films decreased with increasing temperature. The variation of resistance ratio is much bigger in low doping, but the linearity of temperature dependent resistance variation is better in high doping. In case of SiC films deposited with 20 sccm and 100 sccm of $1\%\;NH_3$, the average of TCR(temperature coefficient of resistance) is -3456.1 ppm/$^{\circ}C$ and -1171.5 ppm/$^{\circ}C$, respectively.

• Korean Journal of Materials Research
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• v.9 no.11
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• pp.1049-1054
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• 1999

Two-step growth method is suggested to enhance the alignment of highly oriented diamond films. (100) Si wafers are pretreated with negative biasing of - 200 V at $850^{\circ}C$ for 20 min with 4 % methane in hydrogen plasma. The pretreated wafers are grown under the lst-step growth conditions(2 % CH$_4$ in H$_2$, $810^{\circ}C$) from 2 hr to 35 hr, in order to obtain <100> textured films. The 2nd-step growth(2 % CH$_4$ in H$_2$, $850^{\circ}C$) is carried out to make diamond films having (100) growth planes, which are parallel to the substrate. The alignment of the films after the 1st-step growth, has been analyzed by {111} X-ray pole figure, which is improved abruptly with increasing film thickness. However, the pyramidal surface morphology is inevitable. These morphology is flattened after the 2nd-step growth by developing the (100) facets parallel to the substrate. The alignment of the highly oriented textured films after the two-step growth depends on the thickness of the 1st-step growth film.