• 한국재료학회지
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• 제5권6호
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• pp.706-714
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• 1995

원거리 플라즈마 화학증착법을 이용하여 저온에서 이산화규소박막을 제조하였다. 본 연구 에서는 공정변수인 기판의 온도, 반응기체의 조성 및 분압과 플라즈마 전력에 따른 산화막의 재료적인 물성을 평가하였다. XPS결과에서 산화막은 양론비(O/Si=2)보다 약간 적어 실리콘이 많이 함유된 막으로 나타났다. 이 경우 굴절율과 ESR분석에 의해 미결합된 실리콘의 양이 증가함을 알 수 있었다. SIMS분석에 의해 미량의 질소성분이 계면에 존재하는 것과 실리콘 미결함을 관찰하였다. FT-IR로부터 막내 수소량을 정량화하였으며 결합각 분포는 20$0^{\circ}C$이상에서 열산화막과 비슷한 값을 얻었다. 하지만 열산화막에 비해 높은 식각율을 보여 계면 스트레스에 의해 막내의 결합력이 약해진 것으로 생각된다.

• 한국전기전자재료학회논문지
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• 제22권2호
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• pp.101-106
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• 2009

In this paper, Thin films of $HfO_2$/Hf were deposited on p-type wafer by Atomic Layer Deposition (ALD). We studied the electrical and material characteristics of $HfO_2$/Hf/Si MOS capacitor depending on thickness of Hf metal layer. $HfO_2$ films were deposited using TEMAH and $O_3$ at $350^{\circ}C$. Samples were then annealed using furnace heating to $500^{\circ}C$. Round-type MOS capacitors have been fabricated on Si substrates with $2000\;{\AA}$-thick Pt top electrodes. The composition rate of the dielectric material was analyzed using TEM (Transmission Electron Microscopy), XRD (X-ray Diffraction) and XPS (X-ray Photoelectron Spectroscopy). Also the capacitance-voltage (C-V), conductance-voltage (G-V), and current-voltage (I-V) characteristics were measured. We calculated the density of oxide trap charges and interface trap charges in our MOS device. At the interface between $HfO_2$ and Si, both Hf-Si and Hf-Si-O bonds were observed, instead of Si-O bond. The sandwiched Hf metal layer suppressed the growing of $SiO_x$ layer so that $HfSi_xO_y$ layer was achieved. And finally, the generation of both oxide trap charge and interface trap charge in $HfO_2$ film was reduced effectively by using Hf metal layer.

• 한국재료학회지
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• 제1권4호
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• pp.214-220
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• 1991

실리콘 산화막을 $CHF_{3/}C_2F_6$ 혼합가스를 사용하여 반응성이온 건식식각을 행할 때 실리콘 표면에 형성되는 잔류막과 손상층을 X-선 광전자 분광기(XPS)와 이차이온 질량 분석기(SIMS)를 사용, 연구하였다. 실리콘, 탄소, 산소 및 불소의 angle-resolved XPS분석기술을 이용한 비파괴적 화학결합상태의 깊이분포 분석을 통하여 잔류막의 표면부에 O-F 결합이 존재하며 잔류막은 주로 탄소와 불소의 결합체인 C-F 플리머로 구성되어져 있고 Si-O, Si-C 및 Si-F 결합 등이 존재함을 알았다. 손상층은 실리콘 표면에서 약 60nm 깊이까지 탄소와 불소의 침투에 의해 형성되어져 있음을 알았다.

• 한국진공학회지
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• 제6권2호
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• pp.159-164
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• 1997

X-선 광전자 분광법 (x-ray photoelectron spectroscopy: SPS)과 반사 고에너지 전 자 회절법(reflection high energy electron diffraction: RHEED)을 이용하여 상온과 고온(약 300~$500^{\circ}C$)에서 알칼리금속(AM)/Si(111)7$\times$7표면에 1 monolayer(ML)의 AM을 흡착시키면 Si(111)7$\times$7표면에 비해 산소의 초기 부착 계수(initial sticking coefficient)와 산소의 포화량 은 증가하지 않았다. Si(111)7$\times$7-AM표면에 산소의 주입량을 증가시키면서 측정한 O ls 스 펙트럼으로부터 AM이 흡착된 Si(111)7$\times$7표면에 흡착되는 산소원자는 Si-O, AM-O 두 종 류의 결합형태를 가지는 것으로 생각되며 이중에서 AM-O 결합의 산화과정상에서의 역할 에 대하여 논의하였다. 상온과는 달리 고온에서는, Si(111)3$\times$1-AM표면으로 구조가 변화하 면서 산소의 흡착이 급격히 떨어지는 것을 관측할 수 있었다. 이때 3$\times$1-AM표면을 형성시 키는 AM종류의 산화에 대한 의존성을 살펴보았다.

• 한국결정성장학회지
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• 제8권1호
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• pp.169-178
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• 1998

CaO-$SiO_2-P_2O_5$ 3성분계 유리화 영역(glass forning region)내의 여러조성(A:$SiO_2$- rich조성, B:CaO-rich조성, C:$P_2O_5$-rich조성, D, E:A, B, C의 중간조성)을 가지는 유리분말을 결정화시켰을 때 유리중에 석출되는 결정상(crystal phase)을 분말 XRD로 확인하였다. 여러조성중 apatite(($Ca_{10}(PO_4)_6O$)와 $\beta$-wollastonite($CaSiO_3$)결정이 석출되고, 굽힘강도가 우수한 E조성(CaO 49.4, $SiO_2\;36.8,\;P_2O_5$8.8wt%)을 선택하여 이 조성의 유리분말을 일방향으로 결정화 소결하였다. 제조된 결정화 소결체에 대하여 charaterization을 하고 굽힘강도를 측정하였다. 또한 결정화 소결체와 생체뼈와의 결합성을 조사하기 위하여 유사체액(simulated body fluid)내에서 침적실험을 하였으며, 결정화 소결체의 표면을 thin-film XRD, FT-IR로 분석하였다. 실험결과, apatite와 wollastonite 결정이 석출된 치밀한 결정화 소결체가 얻어졌으며, 이들 결정은 wollastonite 결정의 (202)면이 인상방향에 수직으로 성장하는 경향을 보였다. 또한 제조된 결정화 소결체는 평균 186.9MPa의 굽힘강도를 나타내어 일반적 방법으로 제조되는 결정화 소결체보다 높은 역학적 성질을 보였다. 유사체액내의 침적실험결과, 시료표면위에 apatite 결정층이 3일후부터 형성되어 생체뼈와 화학결합을 이룰 가능성이 있음을 알았다.

• 한국재료학회지
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• 제16권6호
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• pp.394-399
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• 2006

Ferroelectric $HoMnO_3$ thin films were deposited on the Si(100) substrate at $700^{\circ}C$ for 2 hrs by metalorganic chemical vapor deposition (MOCVD) and post-annealed at 850oC by rapid thermal process (RTP). Electrical properties and crystalline phases of $HoMnO_3$ thin films were investigated as a function of postannealing time. Single phase of hexagonal symmetry with c-axis preferred orientation was obtained from $HoMnO_3$ thin films post-annealed at $850^{\circ}C$ for 5 min, while the c-axis preferred orientation was decreased with the increase of post-annealing time, and the thin films post-annealed at $850^{\circ}C$ for 15 min showed the mixture phases of hexagonal and orthorhombic symmetry. P-E (Polarization-Electric field) hysteresis loop of ferroelectric $HoMnO_3$ thin films was observed only for the single phase of hexagonal symmetry, but that was not observed for the mixture phases of the hexagonal and orthorhombic symmetry, which was discussed with the bond valence of Mn ion of crystalline phase. Leakage current density was dependent on the microstructure of thin films as well as the change of valence of Mn ion.

• E2M - 전기 전자와 첨단 소재
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• 제16권9호
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• pp.63.2-64
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• 2003

Epitaxial yttrium-stabilized HfO$_2$ thin films were deposited on p-type (100) Si substrates by pulsed laser deposition at a relatively lower substrate temperature of 550. Transmission electron microscopy observation revealed a fixed orientation relationship between the epitaxial film and Si; that is, (100)Si.(100)HfO$_2$ and [001]Si/[001]HfO$_2$. The film/Si interface is not atomically flat, suggesting possible interfacial reaction and diffusion, X-ray photoelectron spectrum analysis also revealed the interfacial reaction and diffusion evidenced by Hf silicate and Hf-Si bond formation at the interface. The epitaxial growth of the yttrium stabilized HfO$_2$ thin film on bare Si is via a direct growth mechanism without involoving the reaction between Hf atoms and SiO$_2$ layer. High-frequency capacitance-voltage measurement on an as-grown 40-A yttrium-stabilized HfO$_2$ epitaxial film yielded an dielectric constant of about 14 and equivalent oxide thickness to SiO$_2$ of 12 A. The leakage current density is 7.0${\times}$ 10e-2 A/$\textrm{cm}^2$ at 1V gate bias voltage.

• 한국세라믹학회지
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• 제30권5호
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• pp.347-356
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• 1993

In joining alumina ceramics to metal by using Mo-Mn metallizing process the effects of metallizing thickness, temperature, and the composition of paste on the bond strength and the microstructure of joining interface were investigated. The bond strength variation in the range of metallizing temperature, 1350~155$0^{\circ}C$ was more than 150MPa above 145$0^{\circ}C$ and the optimum metallizing thickness was 30${\mu}{\textrm}{m}$. The optimum contents of Mn in Mo-Mn paste was 5% due to the bond strength decrease with the increase of addition. The effect of SiO2 addition in paste on bond strength was saturated around 200MPa. It was also observed that as the particle size of Mo decreased, the joinning with higher bond strength was shown in spite of low metallizing temperature.

• 한국재료학회지
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• 제9권1호
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• pp.35-41
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• 1999

In this study we investigated the effects of process variables on the bond strength, and its dependency upon the interfacial chemistry when the joined $ZrO_2$ toughened $Na\beta$"-alumina to $\alpha$-alumina using B$_2$$O_3$-$SiO_2$-Al$_2$$O_3$-CaO glass sealant. We observed that bond strength is mainly determined by the strength of the glass, which, in turn, depends on the glass composition established after joining reaction. Joining at $950^{\circ}C$ for 15min yielded the highest average bond strength of 66MPa. Different types of interfacial reaction seem to occur at each interface. After joining at $950^{\circ}C$ for 15min we found that Ca and Si diffuse much deeper(~15$\mu\textrm{m}$) into the $\beta$"-alumina composite than into the $\alpha$-alumina(<1$\mu\textrm{m}$) as a result of ion exchange reaction and more effective grain boundary diffusion. Thermal expansion coefficient of the glass was found to have changed more closely to those of the $\beta$"-alumina composite and $\alpha$-alumina, which put the glass under a slight compressive stress.ressive stress.

• 한국재료학회지
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• 제28권2호
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• pp.118-123
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• 2018

5 nm-thick $SiO_2$ layers formed by plasma-enhanced chemical vapor deposition (PECVD) are densified to improve the electrical and interface properties by using nitric acid oxidation of Si (NAOS) method at a low temperature of $121^{\circ}C$. The physical and electrical properties are clearly investigated according to NAOS times and post-metallization annealing (PMA) at $250^{\circ}C$ for 10 min in 5 vol% hydrogen atmosphere. The leakage current density is significantly decreased about three orders of magnitude from $3.110{\times}10^{-5}A/cm^2$ after NAOS 5 hours with PMA treatment, although the $SiO_2$ layers are not changed. These dramatically decreases of leakage current density are resulted from improvement of the interface properties. Concentration of suboxide species ($Si^{1+}$, $Si^{2+}$ and $Si^{3+}$) in $SiO_x$ transition layers as well as the interface state density ($D_{it}$) in $SiO_2/Si$ interface region are critically decreased about 1/3 and one order of magnitude, respectively. The decrease in leakage current density is attributed to improvement of interface properties though chemical method of NAOS with PMA treatment which can perform the oxidation and remove the OH species and dangling bond.