• 한국자기학회지
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• 제10권4호
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• pp.165-170
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• 2000

Fe-Hf-N 연자성 박막의 물리적, 자기적 특성에 미치는 열처리 영향에 대하여 고찰하였다. Fe-Hf-N 연자성 박막을 질소분위기에서 열처리 할 경우 표면에 Fe$_2$O$_3$-Fe$_3$O$_4$으로 구성된 산화층이 생성되었고, 이 산화층 아래 Fe-Hf-O-N층이 생성되었다. 열처리 온도의 증가에 따라 Fe$_2$O$_3$-Fe$_3$O$_4$ 산화층과 Fe-Hf-O-N 층의 두께가 증가하였고, Fe$_2$O$_3$-Fe$_3$O$_4$산화층을 제외한 박막의 두께는 열처리전과 같았다. 열처리한 박막에서 표면에 생성된 Fe$_2$O$_3$-Fe$_3$O$_4$산화층의 두께를 제외하고 계산한 박막의 연자기 특성은 열처리 전의 연자기 특성에 비해 약간 떨어지는 것으로 나타났다. 그러므로, Fe-Hf-O-N층은 박막 전체의 연자기 특성을 크게 떨어뜨리지 않으며, 열처리 후 박막 전체의 연자기 특성은 Fe-Hf-O-N과 Fe-Hf-N의 다층막의 연자기 특성을 나타내는 것으로 생각된다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
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• pp.163-166
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• 2002

We investigated structural and electrical properties of Metal-Oxide-Semiconductor(MOS) structure using Hafnium $oxide(HfO_{2})$ as high-k gate dielectric material. $HfO_{2}$ films are ultrathin gate dielectric material witch have a thickness less than 2.0nm， so it is spotlighted to be substituted $SiO_{2}$ as gate dielectric material. In this paper We have grown $HfO_{2}$ films with pt electrode on P-type Silicon substrate by RF magnetron sputtering system using $HfO_{2}$ target and oserved the property of semiconductor-oxide interface. Using pt electrode, it is necessary to be annealed at ${300^{\circ}C}$. This process is to increase an adhesion ratio between $HfO_{2}$ films with pt electrode. In film deposition process, the deposition time of $HfO_{2}$ films is an important parameter. Structura1 properties are invetigated by AES depth profile, and electrical properties by Capacitance-Voltage characteristic. Interface trap density are measured to observe the interface between $HfO_{2}$ with Si using High-frequency(1MHz) C-V and Quasi - static C-V characteristic.

• 마이크로전자및패키징학회지
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• 제11권2호
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• pp.29-35
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• 2004

65 nm급 게이트 유전체로의 $HfO_2$의 적용을 위해 hydrogen-terminate된 Si 기판과 ECR $N_2$ plasma를 이용하여 SiNx를 형성한 기판 위에 MOCVD를 이용하여 $HfO_2$를 증착하였다. $450^{\circ}C$에서 증착시킨 박막의 경우 낮은 carbon 불순물을 가지며 비정질 matrix에 국부적인 결정화와 가장 적은 계면층이 형성되었으며 이 계면층은 Hf-silicate임을 알 수 있었다. 또한 $900^{\circ}C$, 30초간 $N_2$분위기에서 RTA 결과 $HfO_2/Si$의 single layer capacitor의 경우 계면층의 증가로 인해 EOT가 열처리전(2.6nm)보다 약 1 nm 증가하였다. 그러나 $HfO_2/SiNx/Si$ stack capacitor의 경우 SiNx 계면층은 열처리후에도 일정하게 유지되었으며 $HfO_2$ 박막의 결정화로 열처리전(2.7nm)보다 0.3nm의 EOT 감소를 나타내었으며 열처리후에도 $4.8{\times}10^{-6}A/cm^2$의 매우 우수한 누설전류 특성을 가짐을 알 수 있었다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2008년도 추계학술발표대회 및 제15회 신소재 심포지엄
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• pp.23.1-23.1
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• 2008

• 한국재료학회지
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• 제30권2호
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• pp.99-104
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• 2020

Recent discoveries of ferroelectric properties in ultrathin doped hafnium oxide (HfO₂) have led to the expectation that HfO₂ could overcome the shortcomings of perovskite materials and be applied to electron devices such as Fe-Random access memory (RAM), ferroelectric tunnel junction (FTJ) and negative capacitance field effect transistor (NC-FET) device. As research on hafnium oxide ferroelectrics accelerates, several models to analyze the polarization switching characteristics of hafnium oxide ferroelectrics have been proposed from the domain or energy point of view. However, there is still a lack of in-depth consideration of models that can fully express the polarization switching properties of ferroelectrics. In this paper, a Zr-doped HfO₂ thin film based metal-ferroelectric-metal (MFM) capacitor was implemented and the polarization switching dynamics, along with the ferroelectric characteristics, of the device were analyzed. In addition, a study was conducted to propose an applicable model of HfO₂-based MFM capacitors by applying various ferroelectric switching characteristics models.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.832-835
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• 2001

We report the structural and electrical properties of hafnium oxide (HfO$_2$) films with tungsten silicide (WSi$_2$) metal gate. In this study, HfO$_2$thin films were fabricated by oxidation of sputtered Hf metal films on Si, and WSi$_2$was deposited directly on HfO$_2$by LPCVD. The hysteresis windows in C-V curves of the WSi$_2$HfO$_2$/Si MOS capacitors were negligible (<20 mV), and had no dependence on frequency from 10 kHz to 1 MHz and bias ramp rate from 10 mV to 1 V. In addition, leakage current was very low in the range of 10$^{-9}$ ~10$^{-10}$ A to ~ 1 V, which was due to the formation of interfacial hafnium silicate layer between HfO$_2$and Si. After PMA (post metallization annealing) of the WSi$_2$/HfO$_2$/Si MOS capacitors at 500 $^{\circ}C$ EOT (equivalent oxide thickness) was reduced from 26 to 22 $\AA$ and the leakage current was reduced by approximately one order as compared to that measured before annealing. These results indicate that the effect of fluorine diffusion is negligible and annealing minimizes the etching damage.

• 한국재료학회지
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• 제17권5호
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• pp.263-267
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• 2007

Hafnium oxide $(HfO_2)$ films were deposited on Si(100) substrates by remote plasma-enhanced atomic layer deposition (PEALD) method at $250^{\circ}C$ using TEMAH [tetrakis(ethylmethylamino)hafnium] and $O_2$ plasma. $(HfO_2)$ films showed a relatively low carbon contamination of about 3 at %. As-deposited and annealed $(HfO_2)$ films showed amorphous and randomly oriented polycrystalline structure. respectively. The interfacial layer of $(HfO_2)$ films deposited using remote PEALD was Hf silicate and its thickness increased with increasing annealing temperature. The hysteresis of $(HfO_2)$ films became lower and the flat band voltages shifted towards the positive direction after annealing. Post-annealing process significantly changed the physical, chemical, and electrical properties of $(HfO_2)$ films. $(HfO_2)$ films deposited by remote PEALD using TEMAH and $O_2$ plasma showed generally improved film qualities compare to those of the films deposited by conventional ALD.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2017년도 춘계학술대회 논문집
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• pp.152-152
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• 2017

Titanium and its 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. Silicon (Si) and magnesium (Mg) has a beneficial effect on bone. Si in particular has been found to be essential for normal bone and cartilage growth and development. In vitro studies have shown that Mg 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. Therefore, in this study, Si and Mg coatings on the hydroxyapatite film formed Ti-29Nb-xHf alloys by plasma electrolyte oxidation has been investigated using several experimental techniques. 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 $1050^{\circ}C$. The electrolyte was Si and Mg ions containing calcium acetate monohydrate + calcium glycerophosphate at room temperature. The microstructure, phase and composition of Si and Mg coated oxide surface of Ti-29Nb-xHf alloys were examined by FE-SEM, EDS, and XRD.

• Journal of information and communication convergence engineering
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• 제1권2호
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• pp.67-69
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• 2003

The experimental studies for the etch properties of the oxide grown on silicon substrate, which is in diluted hydrogen fluoride (HF) solution, are presented. Using different ion implantation dosages, dopants and energies, silicon substrate was implanted. The wet etching in diluted HF solution is used as a mean of wafer cleaning at various steps of VLSI processing. It is shown that the wet etch rate of oxide grown on various implanted silicon substrates is a strong function of ion implantation dopants, dosages and energies. This phenomenon has never been reported before. This paper shows that the difference of wet etch rate of oxide by ion implantation conditions is attributed to the kinds and volumes of dopants which was diffused out into $SiO_2$ from implanted silicon during thermal oxidation.

• Archives of Metallurgy and Materials
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• 제64권3호
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• pp.921-924
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• 2019

In this study, ODS ferritic stainless steels were fabricated using a commercial alloy powder, and their microstructures and mechanical properties were studied to develop the advanced structural materials for high temperature service applications. Mechanical alloying and uniaxial hot pressing processes were employed to produce the ODS ferritic stainless steels. It was revealed that oxide particles in the ODS stainless steels were composed of Y-Si-O, Y-Ti-Si-O, and Y-Hf-Si-O complex oxides were observed depending on minor alloying elements, Ti and Hf. The ODS ferritic stainless steel with a Hf addition presented ultra-fine grains with uniform distributions of fine complex oxide particles which located in grains and on the grain boundaries. These favorable microstructures led to superior tensile properties than commercial stainless steel and ODS ferritic steel with Ti addition at elevated temperature.