• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.77.1-77.1
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• 2013

Atomic layer deposition (ALD) is known for its self-limiting reaction, which offers atomic-level controllability of the growth of thin films for a wide range of applications. The self-limiting mechanism leads to very useful properties, such as excellent uniformity over a large area and superior conformality on complex structures. These unique features of ALD provide promising opportunities for future electronics. Although the ALD of Al2O3 film (using trimethyl-aluminum and water as a metal precursor and oxygen source, respectively) can be regarded as a representative example of an ideal ALD based on the completely self-limiting reaction, there are many cases deviating from the ideal ALD reaction in recently developed ALD processes. The nonconventional aspects of the ALD reactions may strongly influence the various properties of the functional materials grown by ALD, and the lack of comprehension of these aspects has made ALD difficult to control. In this respect, several dominant factors that complicate ALD reactions, including the types of metal precursors, non-metal precursors (oxygen sources or reducing agents), and substrates, will be discussed in this presentation. Several functional materials for future electronics, such as higher-k dielectrics (TiO2, SrTiO3) for DRAM application, and resistive switching materials (NiO) for RRAM application, will be addressed in this talk. Unwanted supply of oxygen atoms from the substrate or other component oxide to the incoming precursors during the precursor pulse step, and outward diffusion of substrate atoms to the growing film surface even during the steady-state growth influenced the growth, crystal structure, and properties of the various films.

• 마이크로전자및패키징학회지
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• 제13권1호통권38호
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• pp.51-55
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• 2006

[ $Alq_3$ ]-C545T 형광 시스템을 이용하여 녹색 발광 고성능 OLED를 제작하고 그 특성을 평가하였다. 소자 제작에서 ITO(Indium Tin Oxide)/glass 위에 정공 주입층으로 2-TNATA [4,4',4'-tris(2-naphthyl-phenyl-phenylamino)-triphenylamine]를, 정공수송층으로 NPB [N,N-bis(1-naphthyl)- N,N'-diphenyl-1,1'-biphenyl-4,4-diamine]를 진공 증착하였다. 녹색 발광층으로는 $Ahq_3$를 호스트로, 545T [10-(2-benzo-thiazolyl)-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H,11H-[1]/benzopyrano[6,7,8-ij]-quinolizin-11-one]를 도펀트로 사용하였다. 또한, 전자 수송층으로는 $Alq_3$를 전자 주입층으로는 LiF를 사용하여 ITO/2-TNATA/NPB/$Alq_3$:C-545T/$Alq_3$/LiF/Al 구조의 저분자 OLED를 제작하였다. 본 실험에서 제작된 녹색 OLED는 521 nm의 중심 발광 파장을 가지며, CIE(0.29, 0.65)의 색순도, 그리고 12V의 동작전압에서 7.3 lm/W의 최대 전력효율을 나타내었다.

• 한국재료학회지
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• 제1권1호
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• pp.46-53
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• 1991

반도체 공정의 최종 보호막으로 주로 사용되는 PSG (Phosphosilicate class), USG (Undoped silicate glass) 및 SiN 막을 CVD 방식으로 deposition 하여 각 막의 스트레스를 막 두께 또는 대기중 방치시간의 함수로 조사하고 Al 배선의 stress-migration 관점에서 평가했다. 그 결과 PSG 막과 USG 막은 tensile stress를 나타내고 두께증가에 따라 스트레스가 증가하였고, SiN 막은 두께에 관계없이 일정한 compressive stress를 나타내었다. PSG 막은 현저한 스트레스 경시변화를 보여 대기중에 방치시 2일이내로 tensile stress가 compressive stress로 변화되었다. 그 주 원인은 PSG 막의 수분 흡수 때문인것이 FTIR 분석으로 밝혀졌고, $300^{\circ}C$에서 20분간 anneal 처리로 $2.5{\times}{10^9}\;dyne/cm^2$의 스트레스 회복이 가능하였다. PSG 막이 포함된 복합막의 경우, 복합막 stress는 PSG 막의 방치시간에 따라 변한다. 즉, 복합막의 스트레스는 복합막을 구성하고 있는 막들의 두께의 함수이다. 또 SiN 막의 강한 압축응력을 완화시켜주는 PSG, USG 막의 스트레스가 큰 인장응력을 나타낼수록 Al 배선의 stress-migration 에 대한 저항은 커진다.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2016년도 추계학술대회 논문집
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• pp.197-197
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• 2016

Commercially pure titanium (CP Ti) and Ti-6Al-4V alloys have been widely used for biomedical applications. However, the use of the Ti-6Al-4V alloy in biomaterial is then a subject of controversy because aluminum ions and vanadium oxide have potential detrimental influence on the human body due to vanadium and aluminum. Hence, recent works showed that the synthesis of new Ti-based alloys for implant application involves more biocompatible metallic alloying element, such as, Nb, Hf, Zr and Mo. In particular, Nb and Hf are one of the most effective Ti ${\beta}-stabilizer$ and reducing the elastic modulus. Plasma electrolyte oxidation (PEO) is known as excellent method in the biocompatibility of biomaterial due to quickly coating time and controlled coating condition. The anodized oxide layer and diameter modulation of Ti alloys can be obtained function of improvement of cell adhesion. Manganese(Mn) plays very important roles in essential for normal growth and metabolism of skeletal tissue in vertebrates and can be detected as minor constituents in teeth and bone. Radio frequency(RF) magnetron sputtering in the various PVD methods has high deposition rates, high-purity films, extremely high adhesion of films, and excellent uniform layers for depositing a wide range of materials, including metals, alloys and ceramics like a hydroxyapatite. The aim of this study is to research the Mn coatings on the micro-pore formed Ti-29Nb-xHf alloys by RF-magnetron sputtering for dental applications. Ti-29Nb-xHf (x= 0, 3, 7 and 15wt%, mass fraction) alloys were prepared Ti-29Nb-xHf alloys of containing Hf up from 0 wt% to 15 wt% were melted by using a vacuum furnace. Ti-29Nb-xHf alloys were homogenized for 2 hr at $1050^{\circ}C$. Each alloy was anodized in solution containing typically 0.15 M calcium acetate monohydrate + 0.02 M calcium glycerophosphate at room temperature. A direct current power source was used for the process of anodization. Anodized alloys was prepared using 270V~300V anodization voltage at room. Mn coatings was produced by RF-magnetron sputtering system. RF power of 100W was applied to the target for 1h at room temperature. The microstructure, phase and composition of Mn coated oxide surface of Ti-29Nb-xHf alloys were examined by FE-SEM, EDS, and XRD.

• 한국표면공학회지
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• 제29권6호
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• pp.809-815
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• 1996

$Y_2O_3$-based metal-insulator-semiconductor (MIS) structure on p-Si(100) has been studied. Films were prepared by UHV reactive ionized cluster beam deposition (r-ICBD) system. The base pressure of the system was about $1 \times 10^{-9}$ -9/ Torr and the process pressure $2 \times 10^{-5}$ Torr in oxygen ambience. Glancing X-ray diffraction(GXRD) and in-situ reflection high energy electron diffracton(RHEED) analyses were performed to investigate the crystallinity of the films. The results show phase change from amorphous state to crystalline one with increasingqr acceleration voltage and substrate temperature. It is also found that the phase transformation from $Y_2O_3$(111)//Si(100) to $Y_2O_3$(110)//Si(100) in growing directions takes place between $500^{\circ}C$ and $700^{\circ}C$. Especially as acceleration voltage is increased, preferentially oriented crystallinity was increased. Finally under the condition of above substrate temperature $700^{\circ}C$ and acceleration voltage 5kV, the $Y_2O_3$films are found to be grown epitaxially in direction of $Y_2O_3$(1l0)//Si(100) by observation of transmission electron microscope(TEM). Capacitance-voltage and current-voltage measurements were conducted to characterize Al/$Y_2O_3$/Si MIS structure with varying acceleration voltage and substrate temperature. Deposited $Y_2O_3$ films of thickness of nearly 300$\AA$ show that the breakdown field increases to 7~8MV /cm at the same conditon of epitaxial growing. These results also coincide with XPS spectra which indicate better stoichiometric characteristic in the condition of better crystalline one. After oxidation the breakdown field increases to 13MV /cm because the MIS structure contains interface silicon oxide of about 30$\AA$. In this case the dielectric constant of only $Y_2O_3$ layer is found to be $\in$15.6. These results have demonstrated the potential of using yttrium oxide for future VLSI/ULSI gate insulator applications.