• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.748-752
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• 2004

The Hydrogenated amorphous carbon (a-C:H) thin films are deposited to fabricate suppored layer on silicon substrate with a closed field unbalanced magnetron(CFUBM) sputtering system. This study focuses on the characteristic of Diamond like carbon (DLC) films and Pb(Zr,Ti)$O_3$ (PZT) films for membrane structure. The deposition rate and the surface roughness of DLC fims decrease with DC bias voltage. hardness is 26 GPa at -200 V. Interface of DLC/Si and Pt/DLC layers was excellent.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.2
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• pp.146-149
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• 2017

Si clusters generated during the plasma chemical vapor deposition (CVD) process have a great influence on the quality of the fabricated films. In particular, in hydrogenated amorphous silicon thin films (a-Si:H) used for thin film solar cells, Si clusters are mainly responsible for light-induced degradation. In this study, we investigated the amount of clusters incorporated into thin films using a quartz crystal microbalance (QCM) and specially designed cluster eliminating filters, and investigated the effect of the DC grid mesh in preventing cluster incorporation. Experimental results showed that as the applied voltage of the grid mesh, which is placed between the electrode and the QCM, decreased, the number of clusters incorporated into the film decreased. This is due to the electrostatic force from the grid mesh bias, and this method is expected to contribute to the fabrication of high-quality thin films by preventing Si cluster incorporation.

• Laser Solutions
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• v.13 no.1
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• pp.6-10
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• 2010

Crystallization of 100 nm thick amorphous silicon (a-Si) films on glass substrates was carried out by using a double laser irradiation method. Depending on a-Si deposition method or glass types, the quality of crystallized silicon film varies significantly. For a-Si films deposited with high concentration of impurities, large grains or high crystallinity can not be achieved. Crystallization with different a-Si deposition methods confirmed that for the polycrystallization of a-Si films on glass substrates, controlling the impurity density during substrate preparation is critical.

• ETRI Journal
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• v.31 no.6
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• pp.703-708
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• 2009

Silicon antimony films are studied as resistors for uncooled microbolometers. We present the fabrication of silicon films and their alloy films using sputtering and plasma-enhanced chemical vapor deposition. The sputtered silicon antimony films show a low 1/f noise level compared to plasma-enhanced chemical vapor deposition (PECVD)-deposited amorphous silicon due to their very fine nanostructure. Material parameter K is controlled using the sputtering conditions to obtain a low 1/f noise. The calculation for specific detectivity assuming similar properties of silicon antimony and PECVD amorphous silicon shows that silicon antimony film demonstrates an outstanding value compared with PECVD Si film.

• Journal of the Korean institute of surface engineering
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• v.29 no.5
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• pp.556-562
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• 1996

Carbon nitride (CN) films were synthesized on silicon substrates by a combined ion-beam and laser-ablation method under various conditions; ion-beam energy and ion-beam current were varied. Raman spectroscopy and spectroscopic ellipsometry (SE) were employed to characterize respectively the structural and the optical properties of the CN films. Raman spectra show that all the CN films are amorphous independent of the ion-beam current and the ion-beam energy. Refractive indices, extinction coefficients and optical band gaps which were determined from the measured SE spectra exhibit a significant dependence on the synthesis conditions. Especially, the decrease of the refractive indices and the shrinkage of the optical band gap is noticeable as the ion-beam current and/or the ion-beam energy increase.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.377-380
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• 2004

The phase transition between amorphous and crystalline states in chalcogenide semiconductor films can controlled by electric pulses or pulsed laser beam; hence some chalcogenide semiconductor films can be applied to electrically write/erase nonvolatile memory devices, where the low conductive amorphous state and the high conductive crystalline state are assigned to binary states. GeSbTe(GST), AsSbTe(AST), SeSbTe(SST) used to phase change materials by appling electrical pulses. Thickness of ternary chalcogenide thin films have about 100nm. Upper and lower electrode were made of Al. It is compared with I-V characteristics after impress the variable pulses.

• Journal of IKEEE
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• v.22 no.1
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• pp.213-215
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• 2018

In this study, we fabricate amorphous carbon thin films on silicon substrates by DC sputtering method and investigate the optical property and photothermal characteristics. A representative amorphous carbon thin film has a absorption value of 97% at a wavelength of 1000 nm and shows a temperature increase of $3^{\circ}C$ from $21.1^{\circ}C$ to $24.1^{\circ}C$ during white light irradiation. In addition, the amorphous carbon film has a heating rate four times higher than that of the substrate during light irradiation for 50 sec.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.14 no.1
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• pp.33-36
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• 2004

Amorphous GaN film was deposited using a laser ablation of the highly densified GaN target. Through the surface morphological and compositional analysis of films deposited under various laser energies and Ar gas pressures, the film deposited under the pressure of 10 Pa were found to be amorphous GaN with the smooth surface. In particular, the film at 200 mJ/pulse showed the enhanced crystallinity and stoichiometric composition, compared with those of the films at relatively lower laser energy. The strong band-gap emission at 2.8 eV was observed from amorphous GaN film in the room temperature photoluminescence spectra, showing the highest efficiency in the film at 200 mJ/pulse under 10 Pa.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1992.11a
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• pp.73-76
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• 1992

The amorphous phase of bulk and thin film in the As-Se-S-Ge system was observed by X-ray diffraction. Thermal analysis using DSC, DTA and TGA method has been used for the determination of the glass transition temperature, Tg. The glass transition temperature, Tg for the composition were $238^{\circ}C$ in $As_{40}Se_{15}S_{35}Ge_{10}$ and $231^{\circ}C$ in $AS_{40}Se_{25}S_{25}Ge_{10}$ and $As_{40}Se_{50}Ge_{10}$. The phase seperation of continuous phase and dispersive phase was observed by the optical texture of the polarizing microscope. Also, the glass transition temperature of the thin film was near $200^{\circ}C$. As the results of SEM-EDS analysis, the phase transition of the films by thermal treatment and light illumination was the amorphous to amorphous.

• Journal of the Korean Ceramic Society
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• v.37 no.3
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• pp.219-226
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• 2000

Amorphous Ge20As20Se60 chalcogenide thin films were prepared by spin coating technique from mixed solutions of As40Se60 and Ge40Se60 dissolved in ethylenediamine. Films were prepared at a roating speed of 3500 rpm and spinning time was 10 second and heat-treateed at 27$0^{\circ}C$ for 1 hour. The resulting film thickness and RMS roughness were approximately 340 nm and 15$\AA$. Photostructure changes were investigated with 514.5nm Ar+ laser irradiation and heat-treatment. After Ar+ laser irradiation, transmittance and transmission efficiency decreased respectively up to 24.9% at 2.43 eV and 67.5% at 3.27 eV, and absorption edge shifted toward long wavelength. Optical bandgap changed from 2.03 to 1.83 eV, and absoprtion coefficient and absorption efficiency increased up to 0.33$\times$105cm-1 at 3.37eV and 88.3% at 1.31 eV, respectively. These photodarkening state were recovered reversibly by heat-treatment at 27$0^{\circ}C$ for 1 hour. Photodarkening and thermal bleaching effects by laser irradiation and heat-treatment revealed reversible amorphous-to-amorphous transition varying only coordination number.