• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.111-114
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• 2000

Growth characteristics and microstructure of AlN thin films grown by plasma assisted molecular beam epitaxy on Si substrates have been investigated. Growing temperature and substrate orientation were chosen as major variables of the experiment. Reflection high energy electron diffraction (RHEED), X-ray diffraction (XRD), atomic force microscopy (AFM) and transmission electron microscopy/diffraction (TEM/TED) techniques were employed to characterize the microstructure of the films. On Si(100) substrates, AlN thin films were grown along the hexagonal c-axis preferred orientation at temperature range 850-90$0^{\circ}C$. However on Si(111), the AlN films were epitaxially grown with directional coherency in AlN(0001)/Si(111), AlN(1100)/Si(110), and AlN(1120)/Si(112) at 85$0^{\circ}C$ and the epitaxial coherencry seemed to be slightly distorted with increasing temperature. The microstructure of AlN thin films on Si(111) substrates showed that the films include a lot of crystal defects and there exist micro-gaps among the columns.

• Korean Journal of Materials Research
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• v.29 no.9
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• pp.547-552
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• 2019

In the present study, the thermal conductivity of a silicon nitride($Si_3N_4$) thin-film is evaluated using the dual-wavelength pump-probe technique. A 100-nm thick $Si_3N_4$ film is deposited on a silicon (100) wafer using the radio frequency plasma enhanced chemical vapor deposition technique and film structural characteristics are observed using the X-ray reflectivity technique. The film's thermal conductivity is measured using a pump-probe setup powered by a femtosecond laser system of which pump-beam wavelength is frequency-doubled using a beta barium borate crystal. A multilayer transient heat conduction equation is numerically solved to quantify the film property. A finite difference method based on the Crank-Nicolson scheme is employed for the computation so that the experimental data can be curve-fitted. Results show that the thermal conductivity value of the film is lower than that of its bulk status by an order of magnitude. This investigation offers an effective way to evaluate thermophysical properties of nanoscale ceramic and dielectric materials with high temporal and spatial resolutions.

• Korean Journal of Materials Research
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• v.21 no.2
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• pp.95-99
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• 2011

The microstructure and Cu diffusion barrier property of Ta-Si-N films for various Si and N compositions were studied. Ta-Si-N films of a wide range of compositions (Si: 0~30 at.%, N: 0~55 at.%) were deposited by DC magnetron reactive sputtering of Ta and Si targets. Deposition rates of Ta and Si films as a function of DC target current density for various $N_2/(Ar+N_2)$ flow rate ratios were investigated. The composition of Ta-Si-N films was examined by wavelength dispersive spectroscopy (WDS). The variation of the microstructure of Ta-Si-N films with Si and N composition was examined by X-ray diffraction (XRD). The degree of crystallinity of Ta-Si-N films decreased with increasing Si and N composition. The Cu diffusion barrier property of Ta-Si-N films with more than sixty compositions was investigated. The Cu(100 nm)/Ta-Si-N(30 nm)/Si structure was used to investigate the Cu diffusion barrier property of Ta-Si-N films. The microstructure of all Cu/Ta-Si-N/Si structures after heat treatment for 1 hour at various temperatures was examined by XRD. A contour map that shows the diffusion barrier failure temperature for Cu as a function of Si and N composition was completed. At Si compositions ranging from 0 to 15 at.%, the Cu diffusion barrier property was best when the composition ratio of Ta + Si and N was almost identical.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.10
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• pp.828-833
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• 2000

Growth characteristics and microstructure of AIN thin films grown by plasma assisted molecular beam epitaxy on Si substrates have been investigated. Growing temperature and substrate orientation were chosen as major variables of the experiment. Reflection high energy electron diffraction (RHEED), X-ray diffraction (XRD), atomic force microscopy (AFM) and transmission electron microscopy/diffraction (TEM/TED) techniques were employed to characterize the micorstructure of the films. On Si(100) substrates, AlN thin films were grown along the hexagonal c-axis preferred orientation at temperature range 850-90$0^{\circ}C$. However on Si(111), the AlN films were epitaxially grown with directional coherency in AlN(0001)/Si(111), AlN(1100)/Si(110), and AlN(1120)/Si(112) at 85$0^{\circ}C$ and the epitaxial coherencry seemed to be slightly distorted with increasing temperature. The microstructure of AlN thin films on Si(111) substrates showed that the films include a lot of crystal defects and there exist micro-gaps among the columns.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2007.11a
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• pp.109-111
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• 2007

Pulsed DC 마그네트론 스퍼터링 장치를 이용하여 Polymer 및 Glass 기판 위에 $SiN_{\chi}$ (Silicon Nitride) 박막을 합성 시키고 이들의 구조적, 광학적 특성을 조사하였다. 막두께는 100 nm로 고정하였으며, power mode 및 질소 가스 유량비를 변수로 합성하였다.

• Proceedings of the IEEK Conference
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• 2000.06b
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• pp.115-118
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• 2000

Uncooled pyroelectric infrared detectors based on BST(B $a_{-x}$S $r_{x}$Ti $O_3$) thin films have been fabricated by RF magnetron sputtering and surface Micromachining technology. The detectors form BST thin film ferroelectric capacitors grown by RF magnetron sputtering on N/O/N(S $i_3$ $N_4$/ $SiO_2$/S $i_3$ $N_4$) membrane. The sputtered BST thin film exhibits highly c-axis oriented crystal structure that no poling treatment for sensing applications is required. This is an essential factor to increase the yield for realization of an infrared image sensor. surface-Micromachining technology is used to lower the thermal mass of the detector by giving maximum sensor efficiency Gold-black is evaporated on top of the sensing elements used the thermal evaporator. fabricated uncooled pyroelectric infrared detectors is highly output voltage at the low temperature(1$^{\circ}C$).).).

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.99-99
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• 2003

The growth of GaN on Si is of great interest due to the several advantages : low cost, large size and high-quality wafer availability as well as its matured technology. The crystal quality of GaN is known to be much influenced by the surface pretreatment of Si substrate[1]. In this work, the properties of GaN overlayer grown on ion beam modified Si(111) have been investigated. Si(111) surface was treated RIB with 1KeV-N$_2$$\^$+/(at 1.9 ${\times}$ 10$\^$-5/) to dose ranging from 5${\times}$10$\^$15/ to 1${\times}$10$\^$17/ prior to film growth. GaN epilayers were grown at 1100$^{\circ}C$ for 1 hour after growing AlN buffer layers for 5∼30 minutes at 1100$^{\circ}C$ in Metal Organic Chemical Vapor Deposition (MOCVD). The properties of GaN epilayers were evaluated by X-Ray Diffraction(XRD), Raman spectroscopy, Photoluminescence(PL) and Hall measurement. The results showed that the ion modified treatment markedly affected to the structural, optical and electrical characteristic of GaN layers.

• Journal of the Korean Society for Heat Treatment
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• v.2 no.4
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• pp.1-10
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• 1989

To investigate the influence of temperature on the TiN film, it was deposited on the STC-3 steel and Si-wafer from $TiCl_4/N_2/H_2$ gas mixture by using the radio frequency plasma assisted chemical vapor deposition. The deposition was performed at temperature of $400^{\circ}C-500^{\circ}C$. The results showed that crystalline TiN film was deposited over $480^{\circ}C$, and all specimens showed the crystalline TiN X-ray diffraction peaks after vacuum heat treatment for 3 hrs, at $1000^{\circ}C$, $10^{-5}torr$. While the film thickness was increased above $480^{\circ}C$, it was decreased under $480^{\circ}C$ as temperature increased. And the contents of titanium were increased and it of chlorine were decreased as temperature increased. Because temperature increase was attributed to the increase in the density of TiN film, surface hardness of TiN film was increased with temperature.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.6
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• pp.365-370
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• 2015

Zinc tin oxide transparent thin film transistors (ZTO TTFTs) were fabricated on oxidized $n^+$ Si wafers. The thickness of ~30 nm $Al_2O_3$ films were deposited on the oxidized Si wafers by atomic layer deposition, which acted as the gate insulators of ZTO TTFTs. The $Al_2O_3$ films were rapid-annealed at $400^{\circ}C$, $600^{\circ}C$, $800^{\circ}C$, and $1,000^{\circ}C$, respectively. Active layers of ZTO films were deposited on the $Al_2O_3/SiO_2$ coated $n^+$ Si wafers by rf magnetron sputtering. Mobility and threshold voltage were measured as a function of the rapid-annealing temperature. X-ray photoelectron spectroscopy (XPS) were carried out to observe the chemical bindings of $Al_2O_3$ films. The annealing effects of gate-insulator on the properties of TTFTs were analyzed based on the results of XPS.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.2
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• pp.121-124
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• 2012

The characteristics of Ga-doped zinc oxide (GZO) thin films deposited at different deposition temperatures (TS~250 to $550^{\circ}C$) on 4H-SiC have been investigated. Structural and electrical properties of GZO thin film on n-type 4H-SiC(0001) were investigated by using x-ray diffraction(XRD), atomic force microscopy(AFM), Hall effect measurement, barrier height from I-V curve and Auger electron spectroscopy(AES). XRD $2\theta$ scan shows GZO thin film has preferential orientation with c-axis perpendicular to SiC substrate surface. The lowest resistivity ($\sim1.9{\times}10^{-4}{\Omega}cm$) was observed for the GZO thin film deposited at $400^{\circ}C$. As deposition temperature increases, barrier height between GZO and SiC was increased. Whereas, resistivity of GZO thin films as well as barrier height between GZO and SiC were increased after annealing process in air atmosphere. It has been found that the c-axis oriented crystalline quality as well as the relative amount of activated Ga3+ ions and oxygen vacancy may affect the electrical properties of GZO films on SiC.