• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.343-346
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• 1998

Ultra-thin gate oxide in MOS devices are subjected to high-field stress during device operation, which degrades the oxide and exentually causes dielectric breakdown. In this paper, we investigate the electrical properties of ultra-thin nitrided oxide (NO) and reoxidized nitrided oxide(ONO) films that are considered to be promising candidates for replacing conventional silicon dioxide film in ULSI level integration. We study vriations of I-V characteristics due to F-N tunneling, and time-dependent dielectric breakdown (TDDB) of thin layer NO and ONO depending on nitridation and reoxidation condition, and compare with thermal $SiO_{2}$. From the measurement results, we find that these NO and ONO thin films are strongly depending on its condition and that optimized reoxided nitrided oxides (ONO) films show superior dielectric characteristics, and breakdown-to-change ( $Q_{bd}$ ) performance over the NO films, while maintaining a similar electric field dependence compared to NO layer.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.3
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• pp.277-283
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• 2009

In this paper, aluminum doped zinc oxide (ZnO:Al) thin films on plastic substrate such as poly carbonate (PC), polyethylene terephthalate (PET) were prepared by RF magnetron sputtering method for flexible solar cell applications. Effects of the sputter pressure on the structural, electrical and optical properties were investigated. The crystallinity and the degree of the (002) orientation were deteriorated with increasing the sputter pressure. When the sputter pressure was higher, the conductivity of ZnO:Al films was improved because of the high carrier concentration and the Hall mobility. High quality ZnO:Al films with resistivity as low as $1.9{\times}10^{-3}{\Omega}-cm$ and the optical transmittance over 80 % in the visible region have been obtained on PC substrate at 2 mTorr.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.5
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• pp.373-379
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• 2013

Mg-doped zinc tin oxide (ZTO:Mg) thin films were prepared on glasses by rf magnetron sputtering. $O_2$ was introduced into the chamber during the sputtering. The optical properties of the films as a function of oxygen flow rate were studied. The crystal structure, elementary properties, and depth profiles of the films were investigated by X-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), and secondary ion mass spectrometry (SIMS), respectively. Bottom-gate transparent thin film transistors were fabricated on $N^+$ Si wafers, and the variation of mobility, threshold voltage etc. with the oxygen flow rate were observed.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.209-209
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• 2012

High-efficient transparent conductive oxide (TCO) film-embedding Si heterojunction solar cells were fabricated. An additional doping was not applied for heterojunction solar cells due to the spontaneous junction formation between TCO films and an n-type Si substrate. Three different TCO coatings were formed by sputtering method for an Al-doped ZnO (AZO) film, an indium-tin-oxide (ITO) film and double stacks of ITO/AZO films. An improved crystalline ITO film was grown on an AZO template upon hetero-epitaxial growth. This double TCO films-embedding Si heterojunction solar cell provided significantly enhanced efficiency of 9.23% as compared to the single TCO/Si devices. The effective arrangement of TCO films (ITO/AZO) provides benefits of a lower front contact resistance and a smaller band offset to Si leading enhanced photovoltaic performances. This demonstrates a potential scheme of the effective TCO film-embedding heterojunction Si solar cells.

• Journal of the Korean Vacuum Society
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• v.8 no.3A
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• pp.201-206
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• 1999

Transparent and conduction tin oxide films have been deposited on glass substrates employing the low pressure chemical vapor deposition technique. Tetramethyltin, 1, 1, 1, 2-tetrafluoroethane, and pure oxygen or ozone-containing oxygen were used as the precursor, dopant and oxidant, respectively. In order to examine the role of ozone in the low pressure chemical vapor deposition of tin oxide films, deposition rate, and electrical and optical properties of tin oxide films deposited using ozone-containing oxygen were compared with those using pure oxygen. Tetramethyltin and 1, 1, 1, 2-tetrafluoroethane were chemically activated by thermally initiated decomposition of ozone. Using ozone-containing oxygen under otherwise identical deposition conditions, we succeeded in preparing tin oxide films f better quality at higher deposition rate.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.3
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• pp.269-276
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• 2009

Antimony doped tin oxide ($SnO_2:Sb$) films, which are used as the front contact and back reflector of thin film solar cells, have been deposited by d,c, magnetron sputtering. The dependence of electrical and optical properties of the films on the preparation conditions, such as $O_2$ gas ratio, substrate temperature, annealing temperature was investigated. The sputter gas composition was found to affect the properties of the films. With incorporating $O_2$ gas, the electrical and optical properties of films significantly were improved. The minimum resistivity and optical transmittance over 80 % in visible region were obtained at the oxygen concentration of 30 %, When the substrate temperature was higher, the resistivity of $SnO_2:Sb$ films was decreased, while the absorption edge shifted to shorter wavelength, indicating higher optical band gap. Heat treatment over $600^{\circ}C$ resulted in poorer electrical and optical properties due to SnO phase (102) plane.

• Korean Journal of Materials Research
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• v.30 no.9
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• pp.441-446
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• 2020

Synthesizing nanostructured thin films of oxide semiconductors is a promising approach to fabricate highly efficient photoelectrodes for hydrogen production via photoelectrochemical (PEC) water splitting. In this work, we investigate the feasibility as an efficient photoanode for PEC water oxidation of zinc oxide (ZnO) nanostructured thin films synthesized via a simple method combined with sputtering Zn metallic films on a fluorine-doped tin oxide (FTO) coated glass substrate and subsequent thermal oxidation of the sputtered Zn metallic films in dry air. Characterization of the structural, optical, and PEC properties of the ZnO nanostructured thin film synthesized at varying Zn sputtering powers reveals that we can obtain an optimum ZnO nanostructured thin film as PEC photoanode at a sputtering power of 40 W. The photocurrent density and optimal photocurrent conversion efficiency for the optimum ZnO nanostructured thin film photoanode are found to be 0.1 mA/㎠ and 0.51 %, respectively, at a potential of 0.72 V vs. RHE. Our results illustrate that the ZnO nanostructured thin film has promising potential as an efficient photoanode for PEC water splitting.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.2
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• pp.156-161
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• 2008

The fabrication of vanadium oxide films directly on Si(100) substrates by plasma atomic layer deposition(ALD) with vanadium oxytriisopropoxide(VOIP) and oxygen as the reactants have been performed at temperature ranging from 250 to $450^{\circ}C$. Growth rate of vanadium oxide was $2.8{\AA}$/cycle at $300{\sim}400^{\circ}C$ defined as ALD acceptable temperature window, Vanadium oxide has been shown the different phases at $250^{\circ}C$ and more than $300^{\circ}C$. It has been confirmed that the phase of the films deposited at $250^{\circ}C\;was\;V_2O_5$ type and that of the films above $300^{\circ}C\;was\;VO_2(T)$ type measured at room temperature, respectively. A large change in resistance and small temperature hysteresis corresponding to a temperature has been observed in the vanadium oxide film deposited at temperature $350^{\circ}C$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05b
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• pp.70-73
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• 2002

Thin films of vanadium oxide($VO_{x}$) have been deposited by r.f. magnetron sputtering from $V_{2}O_{5}$ target in gas mixture of argon and oxygen. The oxygen/(oxygen+argon) partial pressure ratio of 0% and 8% is adopted. Crystal structure, chemical composition, molecular structure and optical properties of films sputter-deposited under different oxygen gas pressures and in-situ annealed in vacuum at $400^{\circ}C$ for 1h and 4h are characterized through XRD. RBS, FTlR and optical absorption measurements. The films as-deposited are amorphous and those annealed for time longer than 4h are polycrystalline. $V_{2}O_{5}$ and lower oxides co-exist in sputter-deposited films and as the oxygen partial pressure is increased the films become more stoichiometric $V_{2}O_{5}$. When annealed at $400^{\circ}C$, the as-deposited films are reduced to a lower oxide. It is observed that the oxygen atoms located on the V-O plane of $V_{2}O_{5}$ layer participate more readily in the oxidation and reduction process. The optical transmission of the films annealed in vacuum decreases considerably than the as-deposited films and the optical absorption of all the films increases rapidly between 400 and 550nm.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.260-261
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• 2008

In this study, we investigated the properties of Indium Zinc Oxide (IZO) films prepared in facing targets sputtering (FTS) system at room temperature as function of oxygen contents. As as-deposited films were rapidly thermal annealing on air atmosphere of $400^{\circ}C$ for 30s. As a result, the transmittance of IZO films increased with increasing oxygen flow in the visible range. After rapidly thermal annealing to films, the optical properties of films improved than films deposited at R.T, but the electrical properties decreased. Before RTA treatment, the lowest resistivity IZO is $5.4\times10^{-4}[\Omega{\cdot}cm]$ at oxygen gas flow. But, after RTA treatment, IZO films have the value of lowest resistivity at the lower oxygen gas ratio in compare with before RTA treatment. The resistivity of IZO films is $7.29\times10^{-4}[\Omega{\cdot}cm]$ at pure argon atmosphere.