• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.15 no.3
• /
• pp.214-219
• /
• 2002

In order to elucidate the crystallographic orientation dependence of electrical properties of carbon (C)-doped GaAs epilayers, C incorporation into GaAs epilayers on high-index GaAs substrates with various crystallographic orientations from (100) to (111)A has been performed by a low pressure metalorganic chemical vapor deposition using C tetrabromide ($CBt_4$) as a C source. The hole concentration of C-doped GaAs epilayers rapidly decreases with a hump at (311)A with increasing the offset angle. Although the growth temperature and the V/III ratio are varied, the crystallographic orientation dependence of hole concentration show a same trend. The above behaviors indicate that the bonding strength of As sites on a glowing surface plays an important role in the C incorporation into the high-index GaAs substrates.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.5 no.2
• /
• pp.127-130
• /
• 2005

The structural and electrical properties of InN/GaN multiple quantum wells, which were grown by metalorganic chemical vapor deposition, were characterized by transmission electron microscopy and electroluminescence measurements. As the quantum well growth time was changed, the wavelength was varied from 451 to 531 nm. In the varied current conditions, the blue LED with the InN MQW structures did not have the wavelength shift. With this result, we can expect that the white LEDs with the InN MQW structures do not show the color temperature changes with the variations of applied currents.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.29A no.4
• /
• pp.33-37
• /
• 1992

AlGaAs/GaAs quantum well delta-doped channel FET's have been successfully fabricated using by low-pressure metalorganic chemical vapor deposition(LP-MOCVD). The FET's with a gate dimension of 1.8$\mu$m $\times$ 100$\mu$m have a maximum transconductance of 190 mS/mm and a maximum current density of 425 mA/nm. The devices show extremely broad transconductances with a large voltage swing of 2.4V. The S-parameter measurements have indicated that the current gain and power gain cutoff frequencies of the device were 7 and 15 GHz, respectively. These values are among the best performance reported for GaAs based heterojunction FET's with a similar device geometry.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.18 no.6
• /
• pp.527-531
• /
• 2005

Fully coherent self-assembled InAs quantum dots(QDs) grown on Si (100) substrates by atmospheric pressure metalorganic chemical vapor deposition(APMOCVD) were grown and the effect of growth conditions such as growth rate and growth time on quantum dots' morphology such as densities and sizes was investigated. InAs QDs of 30 - 80 nm in diameters with densities in the range of (0.6 - 1.7) x $10^{10}\;cm^{-2}$ were achieved on Si substrates and InAs layer was changed from 2 dimensional growth to 3 dimensional one at a nominal thickness less than 0.48 ML. This is attributed to the higher ambient pressure of APMOCVD suppressing of In segregation from the 2 dimensional InAs layer. This In segregation looked to disturb the dot formation especially when the growth rate was low so that the dots became less dense and bigger as the growth rate was lower.

• Journal of the Semiconductor & Display Technology
• /
• v.4 no.4 s.13
• /
• pp.9-12
• /
• 2005

Characteristics of ZnO films grown on $Si-SiO_2$ substrates at temperatures of $200\sim400^{\circ}C$ by metalorganic chemical vapor deposition were investigated. The growth rates and mobilities of ZnO films were dependent on growth temperatures. The field-effect mobilities measured in thin-film transistor structure were $15cm^2/Vsec$.

• The Korean Journal of Ceramics
• /
• v.1 no.4
• /
• pp.204-208
• /
• 1995

The microstructure and electrical propetries were investigated for polycrystalline $Ba^{1-x}Sr_xTiO_3$(BST) thin films deposited on Pt/Ti/$SiO_2$(PTSS) and Pt/MgO(PM) substrates by metalorganic chemical vapor deposition (MOCVD). BST films on PTSS have coulmnar and porous structures, while on PM have an equiaxied and dense structure. The dielectric constant and a dissipation factor of BST films on PTSS and 20 fC/$\mu \textrm{cm}^3$ on PTSS and 12fC/$\mu \textrm{cm}^2$ on PM was obtained at an applied electric field of 0.06 MV/cm. Leakage current density of BST films on PM was smaller than that on PTSS. The leakage current density level was about $8\times10^{-8}A/\textrm{cm}^2$ at 0.04MV/cm.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.16 no.1
• /
• pp.12-19
• /
• 2006

Metalorganic chemical vapor deposition (MOCYD) techniques have been applied to fabricate semiconducting ZnO thin films and nanostructures, which are promising for novel optoelectronic device applications using their unique multifunctional properties. The growth and characterization of ZnO thin films on Si and $SiO_2$ substrates by MOCYD as fundamental study to realize ZnO nanostructures was carried out. The precise control of initial nucleation processes was found to be a key issue for realizing high quality epitaxial layers on the substrates. In addition, fabrication and characterization of ZnO nanodots with low-dimensional characteristics have been investigated to establish nanostructure blocks for ZnO-based nanoscale device application. Systematic realization of self- and artificially-controlled ZnO nanodots on $SiO_2/Si$ substrates was proposed and successfully demonstrated utilizing MOCYD in addition with a focused ion beam technique.

• Journal of Korean Vacuum Science & Technology
• /
• v.6 no.2
• /
• pp.88-91
• /
• 2002

InGaN/GaN multiple quantum wells (MQWs) were grown by metalorganic chemical vapor deposition and their structural and optical properties were studied. When the average In content was increased by increasing TMIn flow rate, PL measurement showed little change in PL peak position and large increase in PL intensity instead. Large changes in PL peak position could be achieved by changing growth temperature. We propose the formation of fixed In content, highly In-rich quantum dot-like phases in InGaN MQWs driven by spinodal decomposition.

• Korean Journal of Materials Research
• /
• v.11 no.11
• /
• pp.997-1000
• /
• 2001

Conducting perovskite oxide, $(Ba,Sr)RuO_3(BSR)$, which has many advantages for $(Ba,Sr)TiO_3(BST)$ due to their similarity in crystal structure, lattice constant and chemical composition, was prepared on n-type Si (100) by liquid delivery metalorganic chemical vapor deposition(LDMOCVD). The deposition characteristics of BSR were controlled by gas-phase mass-transfer in the experiment. The BSR films deposited at 50$0^{\circ}C$ and oxygen flow rate of 100 sccm(standard cc/min) showed an average roughness of 22 $\AA$and resistivity of 810 $\mu$$\Omega$-cm. The roughness of BSR films with oxygen flow rate showed a close relationship with the resistivity of films. BSR (110) peak shifted toward lower Bragg angle with increase of x in the$(Ba_x,Sr_{1-x})TiO_3$. The resistivity of BSR films increased from 810 to 924 $\mu$$\Omega$-cm with increase of Ba content(x).

• Proceedings of the Korean Vacuum Society Conference
• /
• 1998.06a
• /
• pp.87-87
• /
• 1998