• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.426.1-426.1
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• 2014

For high performance thin film solar cells, texturing surface, enhancing the optical absorptionpath, is pretty important. Textured ZnO:Al transparent oxide layer of high haze is commonly used in Si thin film solar cells. In this paper, novel deposition method for aluminum doped zinc oxide (ZnO:Al) on glass substrates is presented to improve the haze property. The broccoli structure of ZnO:Al layer was formed on chemically etched glass substrates, which showed high haze value on a wide wavelength range.The etching condition of the glass substrates can change not only the haze values of the ZnO:Al of in-situ growth but alsothe electrical and optical properties of the deposited ZnO:Al films.The etching mechanism of the glass substrate affecting on the surface morphology of the glass will be discussed, which resulted in variation of texture of ZnO:Al layer. The optical properties of substrate morphology were also analyzed with EDS and FTIR results. As a result, the high haze value of 85.4% was obtained in the wavelength range of 300 nm to 1100 nm. Furthermore, low sheet resistance of about 5~18 ohm/sq was achieved for different surface morphologies of the ZnO:Al films.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.398.1-398.1
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• 2014

The $Cu_2ZnSnSe_4$ (CZTSe) thin films solar cell is one of the next generation candidates for photovoltaic materials as the absorber of thin film solar cells because it has optimal bandgap (Eg=1.0eV) and high absorption coefficient of $10^4cm^{-1}$ in the visible length region. More importantly, CZTSe consists of abundant and non-toxic elements, so researches on CZTSe thin film solar cells have been increasing significantly in recent years. CZTSe thin film has very similar structure and properties with the CIGS thin film by substituting In with Zn and Ga with Sn. In this study, As-deposited CZTSe thin films have been deposited onto soda lime glass (SLG) substrates at different deposition condition using Pulsed Laser Deposition (PLD) technique without post-annealing process. The effects of deposition conditions (deposition time, deposition temperature) onto the structural, compositional and optical properties of CZTSe thin films have been investigated, without experiencing selenization process. The XRD pattern shows that quaternary CZTSe films with a stannite single phase. The existence of (112), (204), (312), (008), (316) peaks indicates all films grew and crystallized as a stannite-type structure, which is in a good agreement with the diffraction pattern of CZTSe single crystal. All the films were observed to be polycrystalline in nature with a high (112) predominant orientation at $2{\theta}{\sim}26.8^{\circ}$. The carrier concentration, mobility, resistivity and optical band gap of CZTSe thin films depending on the deposition conditions. Average energy band gap of the CZTSe thin films is about 1.3 eV.

• Journal of Conservation Science
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• v.28 no.2
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• pp.95-99
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• 2012

The compressive strength of PEG along processing concentration and solvent is willing to be measured and proper processing condition for exhibition and storage is also willing to be measured by comparing with dimensional stability. In the advanced research of setting PEG-preprocessing concentration & solvent for freeze drying of waterlogged archaeological wood of high water content, vacuum freeze drying showed the highest dimension stability after 40% PEG-preprocessing of aqueous solution. In this study, the compressive strength increased in proportion of processing concentration and water showed the relatively-higher compressive strength than t-butanol regarding solvent. Especially, it showed that there is no big strength difference between PEG 40% and PEG 50% in aqueous solution by 6.6%(16kgf/$cm^2$). According to the above results, it was recognized that it is most effective to implement freeze drying after 40% PEG-preprocessing when want to dimensional stability and compressive strength simultaneously.

• Journal of the Korean Vacuum Society
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• v.6 no.1
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• pp.69-76
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• 1997

P-type ($Bi_{0.5}Sb_{1.5}Te_3$) and n-type ($Bi_2Te_{2.4} Se_{0.6}$) thermoelectric thin film were deposited on glass and Teflon substrates by the flash evaporation technique. The changes in thermoelectric properties, such as Seebeck coefficient, electrical conductivity, carrier concentration, carrier mobility, thermal conductivity, and figure of merit, were investigated as a function of film thickness and annealing condition. Figures of merit of the thin films annealed at 473 K for 1 hour were improved to be $1.3{\times}10^{-3}K^{-1}$ for p-type and $0.3{\times}10^{-3}K^{-1}$ for n-type, and they were almost independent of film thickness. Temperature sensors were fabricated from the thin films having the above mentioned properties. And thermo-emf, sensitivity, and time constant of the sensors were measured to evaluate their characteristics for temperature sensors. Thin film sensors deposited on Teflon substrates showed better performance than those on glass substrates, and their sensitivity and time constant were 2.91 V/W and 28.2 sec respectively for the sensor of leg width 1 mm$\times$length 16 mm.

• Journal of the Korean Vacuum Society
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• v.6 no.1
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• pp.77-84
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• 1997

Super precision resistor was manufactured by controlling properly the thickness of $TaN_{0.1}$ (negative TCR) and Cr(positive TCR) deposited on cylindrical alumina substrate (diameter: 4 mm, length: 11 mm). Multilayer thin film resistor of $Ta_2O_5/TaN_{0.1}$/Cr/Alumina (substrate) was manufactured by depositing of $Ta_2N_5$ film on $TaN_{0.1}$ film to increase Rs to the level of 1;k{\Omega}/{\box}$ and to passivate the film. Super precision resistor with TCR of $20\pm5 ppm/^{\circ}C$ and Rs of $1\;k{\Omega}/{\box}$ was manufactured by depositing thin layers of about 10 nm $Ta_2O_5$, 100 nm $TaN_{0.1}$ and 50 nm Cr film under the properly controlled sputtering condition.

• Journal of the Korean Vacuum Society
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• v.17 no.2
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• pp.113-116
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• 2008

As the integration in semiconductor display develops, semiconductor process becomes multilayer. In order to form several layer patterns, etching process which uses photoresistor (PR) must be performed in multilayer process. Repeated etching processes which take long time and PR residue cause mortal problems in semiconductor. To overcome such problems, we studied about the solution which eliminates PR effectively by using normal dry and wet etching method using plasma activated PR strip solvent in liquid condition. At first, we simulate the device which activates the plasma and make sure whether gas flow in device is uniform or not. Under activated plasma, etching effect is elevated. This improvement reduces etching time as well as display production time of semiconductor process. Generally, increasing etching process increases environmental hazards. Reducing etching process can save the etchant and protect environment as well.

• Journal of the Korean Vacuum Society
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• v.16 no.5
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• pp.311-321
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• 2007

We have researched the chemical defects of NiO ultrathin films grown on Ag(001) by x-ray photoelectron spectroscopy. In particular, O 1s and Ni 2p spectra were analyzed consistently with control film thickness, $O_2\;and\;H_2O$ partial pressure and substrate temperature. As a result, we could identify each chemical defect. In addition, we suggest the optimum growth condition to minimize the defect density.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.246-246
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• 2010

As the trench width in the interconnect technology decreases down to nano-scale below 50 nm, superconformal gap-filling process of Cu becomes very critical for Cu interconnect. Obtaining superconfomral gap-filling of Cu in the nano-scale trench or via hole using MOCVD is essential to control nucleation and growth of Cu. Therefore, nucleation of Cu must be suppressed near the entrance surface of the trench while Cu layer nucleates and grows at the bottom of the trench. In this study, suppression of Cu nucleation was achieved by treating the Ru barrier metal surface with capacitively coupled hydrogen plasma. Effect of hydrogen plasma pretreatment on Cu nucleation was investigated during MOCVD on atomic-layer deposited (ALD)-Ru barrier surface. It was found that the nucleation and growth of Cu was affected by hydrogen plasma treatment condition. In particular, as the plasma pretreatment time and electrode power increased, Cu nucleation was inhibited. Experimental data suggests that hydrogen atoms from the plasma was implanted onto the Ru surface, which resulted in suppression of Cu nucleation owing to prevention of adsorption of Cu precursor molecules. Due to the hydrogen plasma treatment of the trench on Ru barrier surface, the suppression of Cu nucleation near the entrance of the trenches was achieved and then led to the superconformal gap filling of the nano-scale trenches. In the case for without hydrogen plasma treatments, however, over-grown Cu covered the whole entrance of nano-scale trenches. Detailed mechanism of nucleation suppression and resulting in nano-scale superconformal gap-filling of Cu will be discussed in detail.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.168-168
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• 2010

Transparent conduction oxides (TCOs) films is extensively reported for optoelectronic devices application such as touch panels, solar cells, liquid crystal displays (LCDs), and organic light emitting diodes(OLEDs). Among the many TCO film, indium tin oxide(ITO) is in great demand due to the growth of flat panel display industry. However, indium is not only high cost but also its deposits dwindling. Therefore, many studies are being done on the transparent conductive oxides(TCOs). We fabricated a target of IZTO(In2O3:ZnO:SnO2=70:15:15 wt.%) reduced indium. Then, IZTO thin films were deposited on glass substrates by pulsed DC magnetron sputtering with various oxygen flow ratio. The substrate temperature was fixed at the room temperature. We investigated the electrical, optical, structural properties of IZTO thin films. The electrical properties of IZTO thin films were dependent on the oxygen partial pressure. As a result, the most excellent properties of IZTO thin films were obtained at the 3% of oxygen flow rate with the low resistivity of $7.236{\times}10^{-4}{\Omega}cm$. And also the optical properties of IZTO thin films were shown the good transmittance over 80%. These IZTO thin films were used to fabricated organic light emitting diodes(OLEDs) as anode and the device performances studied. The OLED with an IZTO anode deposited at optimized deposition condition showed good brightness properties. Therefore, IZTO has utility value of TCO electrode although it reduced indium and we expect it is possible for the IZTO to apply to flexible display due to the low processing temperature.

• Korean Journal of Food Science and Technology
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• v.35 no.6
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• pp.1110-1116
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• 2003

The effects of packaging methods on the storage quality of minimally processed (prepeeled) onions were investigated to determine the optimal packing design. Various packaging treatments used for modifying headspace atmospheres included two passive MAP using LDPE and PP films, two active MAP using a gas mixture of 20% $O_2/10%\;CO_2/balance\;N_2$ and an ethylene scavenging sachet, and moderate vacuum packaging (MVP). The quality attributes of onion samples were evaluated periodically in terms of flesh weight loss, color of cut surface, decay ratio, microbial counts, and sensory properties during storage at $10^{\circ}C$ for 28 days. Packaging methods did not significantly influence surface color, weight loss, and microbiological populations of mesophiles, psychrotrophs, and lactic acid bacteria. They did, however, affect sensory characteristics as well as decay occurrence. Results indicated that seal-packaging with a gas-permeable plastic film under a mild vacuum condition could retain better onion quality in terms of microbial decay and visual sensory aspects as compared with the other packages.