• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.938-941
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• 2000

SrBi$_2$Ta$_2$$O_{9}$(SBT) thin films were etched in Ar/SF$_{6}$ and Ar/CHF$_3$gas plasma using magnetically enhanced inductively coupled plasma(MEICP) system. The etch rates of SBT thin film were 1500$\AA$/min in SF$_{6}$/Ar and 1650 $\AA$/min in Ar/CHF$_3$at a rf power of 600W a dc-bias voltage of -l50V. a chamber pressure of 10 mTorr. In order to examine the chemical reactions on the etched SBT thin film surface , x-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS) were examined. In etching SBT thin film with F-base gas plasma, M(Sr. Bi. Ta)-O bonds are broken by Ar ion bombardment and form SrFand TaF$_2$ by chemical reaction with F. SrF and TaF$_2$are removed more easily by Ar ion bombardmentrdment

• 한국전기전자재료학회논문지
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• 제14권9호
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• pp.714-719
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• 2001

SrBi$_2$Ta$_2$$O_{9}$ thn films were etched in inductively coupled Cl$_2$/CF$_4$/Ar plasma. THe maximum etch rate was 1060 $\AA$/min at a Cl$_2$/(Cl$_2$+CF$_4$+Ar)=0.2. The 20% additive Cl$_2$ into CF$_4$/Ar plasma decreased carbon and fluorine radicals, but increased Cl radicals. Sr was effectively removed by reacting with Cl radical because the boiling point of SrCl$_2$(125$0^{\circ}C$) is lower than that of SrF$_2$(246$0^{\circ}C$). The chemical reactions on the etched surface were studied with x-ray photoelectron spectroscopy and secondary ion mass spectrometry. The etching profile was evaluated by using scanning electron microscopy.y.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
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• pp.159-162
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• 2002

Ferroelectric $YMnO_{3}$ thin films were etched with $Ar/Cl_{2}$ and $CF_{4}/Cl_{2}$ inductivly coupled plasma (ICP). The maximum etch rate of $YMnO_{3}$ thin film was $300{\AA}/min$ at a $Ar/Cl_{2}$ gas mixing ratio of 2/8, a RF power of 800 W, a dc bias of 200 V, a chamber pressure of 15 mTorr, and a substrate temperature of ${30^{\circ}C}$. From the X-ray photoelectron spectroscopy (XPS) analysis ， yttrium not only etched by chemical reactions with Cl radicals, but also assisted by Ar ion bombardments in $Ar/Cl_{2}$ plasma. In $CF_{4}/Cl_{2}$ plasma, yttrium are remained on the etched surface of $YMnO_{3}$ and formed of nonvolatile YFx compounds Manganese etched effectively by chemical reactions with Cl and F radicals. From the X-ray diffraction (XRD) analysis, the (0004) diffraction peak intensity of the $YMnO_{3}$ thin film etched in $Ar/Cl_{2}$ plasma shows lower value than that in $CF_{4}/Cl_{2}$ plasma. It is indicates that the crystallinty of $YMnO_{3}$ thin film is more easily damaged by the Ar ion bombardment than the changes of stoichiometry due to nonvolatile etch by-products.

• 한국전기전자재료학회논문지
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• 제14권12호
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• pp.959-964
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• 2001

We investigated the etching characteristics of YMnO$_3$ thin films in high-density plasma etching system. In this study, YMnO$_3$ thin films were etched with CF$_4$/Ar gas chemistries in inductively coupled plasma(ICP). Etch rates of YMnO$_3$ increased up to 20% CF$_4$ in CF$_4$/(CF$_4$+Ar), but decreased with furthermore increasing CF$_4$ in CF$_4$/(CF$_4$+Ar). In optical emission spectroscopy (OES) analysis, F radical and Ar* ions in plasma at various gas chemistries decreased with increasing CF$_4$ content. Chemical states of YMnO$_3$ films exposed in plasma were investigated with x-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). There is a chemical reaction between metal (Y, Mn) and F and metal-fluorides were removed effectively by Ar ion sputtering. YF$_{x}$, MnF$_{x}$ such as YF, YF$_2$, YF$_3$ and MnF$_3$ were detected using SIMS analysis. The etch slope is about 65$^{\circ}$ and cleasn surface. surface of the etched YMnO$_3$ thin films was investigated with X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). The etch profile was also investigated by scanning electron microscopy (SEM).EM).

• 한국주조공학회지
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• 제15권2호
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• pp.175-183
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• 1995

It is difficult to remove such interstitial impurities as sulfur, oxygen, hydrogen and carbon in Fe-Ni alloys. Thermodynamic and kinetic studies were carried out on the behavior of hydrogen gas, oxygen gas, Si, Al and slag, and the reaction time by the $Ar/Ar-H_2$ plasma and electron beam melting. After the addition of Al, Si, they were melted by Ar plasma with reaction time changed. 80%Ni-Fe alloys showed a better deoxidation than 36%Ni-Fe alloys. At $Ar-H_2$ plasma melting, the deoxidation was significant. In the case of the electron beam melting, the residual oxygen was higher than in Ar plasma melting because electron beam melting temperature was lower than that of Ar plasma. For the decaburization, it was melted by $Ar-O_2$ plasma melting, which could remove effectively carbon by activated oxygen in plasma. We added slag to Fe-Ni alloys for the desulfurization. As the result of this experiments, the amount of residual sulfur was not changed according to the slag ratio and reaction time.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2003년도 춘계학술발표회 초록집
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• pp.43-43
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• 2003

• 한국재료학회지
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• 제21권9호
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• pp.509-514
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• 2011

In this study, optical emission spectroscopy was used to monitor the plasma produced during the RF magnetron sputtering of a $BaTiO_3$ target. The intensities of chemical species were measured by real time monitoring with various discharge parameters such as RF power, pressure, and discharge gas. The emission lines of elemental and ionized species from $BaTiO_3$ and Ti targets were analyzed to evaluate the film composition and the optimized growth conditions for $BaTiO_3$ films. The emissions from Ar(I, II), Ba(I, II) and Ti(I) were found during sputtering of the $BaTiO_3$ target in Ar atmosphere. With increasing RF power, all the line intensities increased because the electron density increased with increasing RF power. When the Ar pressure increased, the Ba(II) and Ti(I) line intensity increased, but the $Ar^+$ line intensity decreased with increasing pressure. This result shows that high pressure is of greater benefit for the ionization of Ba than for that of Ar. Oxygen depressed the intensity of the plasma more than Ar did. When the Ar/$O_2$ ratio decreased, the intensity of Ba decreased more sharply than that of Ti. This result indicates that the plasma composition strongly depends on the discharge gas atmosphere. When the oxygen increased, the Ba/Ti ratio and the thickness of the films decreased. The emission spectra showed consistent variation with applied power to the Ti target during co-sputtering of the $BaTiO_3$ and Ti targets. The co-sputtered films showed a Ba/Ti ratio of 1.05 to 0.73 with applied power to the Ti target. The films with different Ba/Ti ratios showed changes in grain size. Ti excess films annealed at $600^{\circ}C$ did not show the second phase such as $BaTi_2O_5$ and $TiO_2$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기물성,응용부문
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• pp.117-118
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• 2006

In this work, we investigated etching characteristics of $HfO_2$ thin film and Si using inductive coupled plasma (ICP) system. The ion energy distribution functions in an inductively coupled plasma was analyzed by quadrupole mass spectrometer with an electrostatic ion energy analyzer. The maximum etch rate of $HfO_2$ is 85.5 nm/min at a $BCl_3/(BCl_3+Ar)$ of 20% and decreased with further addition of $BCl_3$ gas. From the QMS measurements, the most dominant positive ion energy distributions (IEDs) showed a maximum at 20 % of $BCl_3$. These tendency was very similar to the etch characteristics. This result agreed with the universal energy dependency of ion enhanced chemical etching yields. And the maximum selectivity of $HfO_2$ over Si is 3.05 at a O2 addition of 2 sccm into the $BCl_3/(BCl_3+ Ar)$ of 20% plasma.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.121-121
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• 2011

Graphene formed by chemical vapor deposition was exposed to the various plasmas of Ar, O2, N2, and H2 to examine its effects on the bonding properties of graphene to metal. Upon the Ar plasma exposure of patterned graphene, the subsequently deposited metal electrodes remained intact, enabling successful fabrication of field effect transistor (FET) arrays. The effects of enhancing adhesion between graphene and metals were more evident from O2 plasmas than Ar, N2, and H2 plasmas, suggesting that chemical reaction of O radicals induces hydrophilic property of graphene more effectively than chemical reaction of H and N radicals and physical bombardment of Ar ions. From the electrical measurements (drain current vs. gate voltage) of field effect transistors before and after Ar plasma exposure, it was confirmed that the plasma treatment is very effective in controlling bonding properties of graphene to metals accurately without requiring buffer layers.

• 한국전기전자재료학회논문지
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• 제20권7호
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• pp.611-614
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• 2007

The changes in the work $function({\Phi}_w)$ in the MgO protective layers after $plasma(Ar,\;H_2)$ treatment have been studied using ${\Upsilon}-focused$ ion beam $({\Upsilon}-FIB)$ system. The ${\Phi}_w$ was determined as follows: Ar-plasma $treatment({\Phi}_w=4.52eV)$, $H_2-plasma$ $treatment({\Phi}_w=5.65eV)$, and non-plasma $treatment({\Phi}_w=4.64eV)$. The results indicated that the H-plasma could not make any effective physical etching due to the small masses of hydrogen atoms and molecules while the hydration of H-plasma could grow some contaminating materials on the surface of MgO.