• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.28-38
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• 2020

Semiconductor deposition equipment is an important example of Complex Products and Systems (CoPS) and requires in-depth understanding of user requirements. For this reason, we analyzed and compared users' and producers' perspectives on the quality attributes of semiconductor deposition equipment using the Kano model. The results show that the patterns of users' perspectives were different from those of producers. Out of 22 level-2 quality attributes, producers evaluated all 22 attributes as attractive qualities, but users evaluated only 6 as "attractive," 10 as "indifferent," 2 as "must have," and 4 as "other." Although all quality attributes were attractive for producers, only those related to reliability were attractive or must-have qualities, and all others were "indifferent." This result implies that the perspectives on quality attributes may be different between users and producers, and producers should revise their perspectives and strategies. In addition, the results support the characteristics of CoPS suggested by literature implying that performance is more important than economies of scale and cost reduction. It is suggested that producers of semiconductor deposition equipment strategize their approaches to users by considering the characteristics of CoPS.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.211-211
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• 1999

Titanium nitride (TiN) thin films have useful properties including high hardness, good electrical conductivity, high melting point, and chemical inertness. The applications have included wear-resistant hard coatings on machine tools and bearings, decorative coating making use of the golden color, thermal control coatings for widows, and erosion resistant coatings for spacecraft plasma probes. For all these applications as feature sizes shrink and aspect ratios grow, the issue of good step coverage becomes increasingly important. It is therefore essential to manufacture conformal coatings of TiN. The growth of TiN thin films by chemical vapor deposition (CVD) is of great interest for achieving conformal deposition. The most widely used precursor for TiN is TiCl4 and NH3. However, chlorine impurity in the as-grown films and relatively high deposition temperature (>$600^{\circ}C$) are considered major drawbacks from actual device fabrication. To overcome these problems, recently, MOCVD processes including plasma assisted have been suggested. In this study, therefore, we have doposited Ti(C, N) thin films on Si(100) and D2 steel substrates in the temperature range of 150-30$0^{\circ}C$ using tetrakis diethylamido titanium (TDEAT) and titanium isopropoxide (TIP) by pulsed DC plamsa enhanced metal-organic chemical vapor deposition (PEMOCVD) method. Polycrystalline Ti(C, N) thin films were successfully grown on either D2 steel or Si(100) surfaces at temperature as low as 15$0^{\circ}C$. Compositions of the as-grown films were determined with XPS and RBS. From XPS analysis, thin films of Ti(C, N) with low oxygen concentration were obtained. RBS data were also confirmed the changes of stoichiometry and microhardness of our films. Radical formation and ionization behaviors in plasma are analyzed by optical emission spectroscopy (OES) at various pulsed bias and gases conditions. H2 and He+H2 gases are used as carrier gases to compare plasma parameter and the effect of N2 and NH3 gases as reactive gas is also evaluated in reduction of C content of the films. In this study, we fond that He and H2 mixture gas is very effective in enhancing ionization of radicals, especially N resulting is high hardness. The higher hardness of film is obtained to be ca. 1700 HK 0.01 but it depends on gas species and bias voltage. The proper process is evident for H and N2 gas atmosphere and bias voltage of 600V. However, NH3 gas highly reduces formation of CN radical, thereby decreasing C content of Ti(C, N) thin films in a great deal. Compared to PVD TiN films, the Ti(C, N) film grown by PEMOCVD has very good conformability; the step coverage exceeds 85% with an aspect ratio of more than 3.

• Journal of the Korean Vacuum Society
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• v.19 no.1
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• pp.14-21
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• 2010

Ge is one of the attractive channel materials for the next generation high speed metal oxide semiconductor field effect transistors (MOSFETs) due to its higher carrier mobility than Si. But the absence of a chemically stable thermal oxide has been the main obstacle hindering the use of Ge channels in MOS devices. Especially, the fabrication of gate oxide on Ge with high quality interface is essential requirement. In this study, $HfO_xN_y$ thin films were prepared by plasma-enhanced atomic layer deposition on Ge substrate. The nitrogen was incorporated in situ during PE-ALD by using the mixture of nitrogen and oxygen plasma as a reactant. The effects of nitrogen to oxygen gas ratio were studied focusing on the improvements on the electrical and interface properties. When the nitrogen to oxygen gas flow ratio was 1, we obtained good quality with 10% EOT reduction. Additional analysis techniques including X-ray photoemission spectroscopy and high resolution transmission electron microscopy were used for chemical and microstructural analysis.

• Clean Technology
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• v.24 no.3
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• pp.183-189
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• 2018

Hollow carbon spheres (HCS) and carbon spheres (CS) were prepared by a hydrothermal reaction and they were introduced as a substrate for the deposition of $MnO_2$ nanoparticles. The $MnO_2$ nanoparticles were deposited on the carbon surface by a chemical redox deposition method. After deposition, the $MnO_2$ nanoparticles were uniformally distributed on the carbon surface in a slit-shape, and sparse $MnO_2$ slits appeared on the HCS surface. The $MnO_2-HCS$ showed an initial specific capacitance of $164.1F\;g^{-1}$ at scan rate of $20mv\;s^{-1}$, and after 1,000 cycles, the specific capacitance was maintained to $141.3F\;g^{-1}$. The capacity retention of $MnO_2-HCS$ and $MnO_2-CS$ were calculated to 86% and 78% in the cycle performance test up to 1,000 cycles, respectively. $MnO_2-HCS$ showed a good cycle stability due to the mesoporous hollow structure which can cause a faster diffusion of the electrolyte and can easily adsorb and desorb $Na^+$ ions on the surface of the electrode.

• Korean Journal of Materials Research
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• v.4 no.5
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• pp.550-555
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• 1994

The effects of RTA treatment on the leakage current have been studied for tantalum pentoxide( $Ta_2O_5$) films deposited by PECVD on P-type(100) Si substrate using $TaCl_5$(99.99%) and $N_2O$(99.99%) gaseous mixture. The refractive index increased with increasing the deposition temperature and the maximum deposition rate was obtained at $500^{\circ}C$. The Ta-0 bond peak intensity of as-deposited $Ta_2O_5$ increased with increasing the deposition temperature through FT-IR analysis and the leakage current value was decreased with increasing the deposition temperature. The small leakage current value obtained after RTA treatment of as-deposited $Ta_2O_5$ was found to be due to the reduction of 0-deficient structure in the film. The increases of the oxygen coacentration and the Ta-0 bond peak intensity in the film after RTA treatment were measured by AES and FT-IR analyses.

• Clean Technology
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• v.29 no.1
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• pp.71-75
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• 2023

In general, the presence of non-selective intercrystalline (grain boundary) defects in polycrystalline metal-organic framework (MOF) or zeolite membranes, which are known to be ca. 1 nm in size, causes lower membrane performance (selectivity) than the intrinsically expected. In this study we show that applying a thin polymeric coating of polydimethylsiloxane (PDMS) on a polycrystalline MOF membrane is effective to cap the non-selective intercrystalline defects and therefore improve membrane performance. To demonstrate the concept, first, polycrystalline UiO-66, one of Zr-based MOFs, membranes were prepared by an in-situ solvothermal growth. By controlling membrane growth condition with respect to growth temperature, we were able to obtain polycrystalline UiO-66 membranes at 150 ℃ with intercrystalline defects of which the quantity is not significant, so it can be plugged by the suggested PDMS deposition. Second, their performances were compared before and after the PDMS deposition. As expected, the PDMS deposition ended up with a noticeable increase in CO₂/N₂ ideal selectivity from 6 to 14, indicating successful intercrystalline defect plugging. However, the enhancement in CO₂/N₂ selectivity was accompanied by a significant reduction in CO₂ permeance from 5700 to 33 GPU because the PDMS deposition not only plugs defects but also forms a continuous coating on membrane surface, adding an additional transport resistance.

• Analytical Science and Technology
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• v.9 no.2
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• pp.161-167
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• 1996

An investigation was made of possible ways in which one could control the relative rates of cadmium deposition and hydrogen evolution by binary additive systems. Benzyl alcohol was employed as an additives due to its ability to form a hydrophobic film which inhibit the electroreduction of water to form hydrogen. The second additive was chosen to make the cadmium(II) ion less hydrophilic and increase its ability to cross the hydrophobic benzyl alcohol film and be electrodeposited at the cathode. It was shown by voltammetric and current efficiency studies that ion pairing and complexing additives could be used to accelerate the reduction of cadmium in the presence of the benzyl alcohol film. It was also shown that the benzyl alcohol film lowered the dielectric constant of the solution near the electrode enough to obtain ion pairing between the sodium ion and the negative chloride complex of cadmium and accelerate the reduction of the cadmium. This acceleration did not occur in the sulfate solution in the absence of chloride since cadmium(II) is primarily present as a positive aquo complex and ion pairing, if it occured, would not accelerate but would hinder reduction of cadmium.

• Journal of Powder Materials
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• v.18 no.2
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• pp.159-167
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• 2011

The influence of sulfate on the selective catalytic reduction of $NO_x$ on the Ag/$Al_2O_3$ catalyst was studied when $CH_4$ was used as a reducing agent. Various preparation methods influenced differently on the $deNO_x$ activity. Among the methods, cogelation precipitation gave best activity. When sulfates were formed on the surfaces of samples prepared by impregnated and deposition precipitation, $deNO_x$ activity was enhanced as long as suitable forming condition is satisfied. The major sulfate formed in Ag/$Al_2O_3$ catalyst was the aluminum sulfate and it seems that this sulfate acted as a promoter. When Mg was added to the Ag/$Al_2O_3$ catalyst it promoted $deNO_x$ activity at high temperature. Intentionally added sulfate also enhanced $deNO_x$ activity, when their amount was confined less than 3 wt%.

• Journal of the Korean Magnetics Society
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• v.14 no.1
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• pp.13-17
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• 2004

We have investigated the effect of Hf insertion in the Al oxide tunnel barrier on the properties of magnetic tunnel junctions (MTJs). MTJs with Hf inserted barrier show the higher tunnel magnetoresistance (TMR) ratio and less temperature and bias voltage dependence of TMR than MTJs with a conventional Al$_2$O$_3$ barrier. The enhancement of TMR ratio and the reduction of the temperature and bias voltage dependence might be due to the reduction of defects in the barrier. Al-Hf oxide was formed by depositing Al and Hf simultaneously, and oxidizing the compound films. The TMR ratio of 36% was almost the same value as that with Hf inserted barrier. This implies that the inserted Hf layers mixed with Al layers during deposition or oxidation, and they might form Al Hf oxide barriers. This compound Al Hf oxide formation may be responsible to reduction of defect concentration which enhanced the TMR ratio and reduced temperature and bias-voltage dependence.

• Clean Technology
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• v.4 no.1
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• pp.6-23
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• 1998

Recently, semiconductor industry has grown rapidly because of the large demand for electronic devices and equipment. The semiconductor industries have also played an important role on the economic growth in Korea. As the environmental regulations become strict, the proper environmental management and the well-developed waste minimization technologies in semiconductor industries are two of urgent problems to be solved. The semiconductor manufacturing process consists of a series of continuous chemical processes, such as cleaning, oxidation, diffusion, photolithography, etching and film deposition. During the processes, various environmentally hazardous wastes are produced. The wastes may be classified as wastewater, gaseous pollutants, and solid wastes. For waste minimization, the substitution of raw materials and process optimization techniques are used, while the selective destruction technologies of toxic chemicals contained in the wastes have been reported. Also, new technologies have been developed for source reduction and waste reduction, such as reduction of toxic chemical use and substitution of hazardous liquids with gaseous reactants or solvent.