• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.17 no.4
• /
• pp.361-366
• /
• 2004

The interface stability of Ta-Mo alloy film on SiO$_2$ was investigated. Ta-Mo alloy films were formed by co-sputtering method, and the alloy composition was varied by controlling Ta and Mo sputtering power, When the atomic composition of Ta was about 91％, the measured work function was 4.24 eV that is suitable for NMOS gate. To identify interface stability between Ta-Mo alloy film and SiO$_2$, C-V and XRD measurements were performed on the samples annealed with rapid thermal processor between $600^{\circ}C$ and 90$0^{\circ}C$. Even after 90$0^{\circ}C$ rapid thermal annealing, excellent interface stability and electrical properties were observed. Also, thermodynamic analysis was studied to compare with experimental results.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.04b
• /
• pp.9-12
• /
• 2004

This paper investigated the stability of Ta-Mo alloy on thin gate dielectric. Ta-Mo alloy was deposited by using co-sputtering process after thermal growing of 3.4nm and 4.2nm silicon dioxide. When the sputtering power of Ta and Mo were 100W and 70W, respectively, the suitable work function for NMOS gate electrode, 4.2eV, could obtain. To prove interface thermal stability of thin film gate dielectric and Ta-Mo alloy, rapid thermal annealing was performed at $600^{\circ}C$ and $700^{\circ}C$ for 10sec in Ar ambient. The results of interface reaction were surveyed by change of silicon dioxide thickness and work function after annealing process. Also, the reliability of alloy gate and gate dielectric could be confirmed by quantity of leakage current. Ta-Mo alloy was showed low sheet resistance and thermal stability, namely, little change of gate dielectric and work function, after $700^{\circ}C$ annealing process.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2005.07a
• /
• pp.157-159
• /
• 2005

MOS capacitors were fabricated to study electrical and chemical properties of Ta-Mo metal alloy with $ZrO_2$. The work function of Ta-Mo alloy were varied from 4.1eV to 5.1eV by controlling the composition. When the atomic composition of Mo is 10%, good thermal stability up to $800^{\circ}C$ was observed and work function of MOS capacitor was 4.1eV, compatible for NMOS application. But pure Ta exhibited very poor thermal stability. After $600^{\circ}C$ annealing, equivalent oxide thickness of tantalum gate MOS capacitor was continuously decreased. Barrier heights of Ta-Mo alloy and pure metal that supported the work function values were calculated from Fowler-Nordheim analysis. As a result of these electrical?experiments, Ta-Mo metal alloy with $ZrO_2$ is excellent gate electrode for NMOS.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.11a
• /
• pp.3-6
• /
• 2003

This paper describes the interface stability of Ta-Mo alloy metal on $SiO_2$ Alloy was formed by co-sputtering method, and the alloy composition was varied by controlling Ta and Mo sputtering power. When the atomic composition of Ta was about 91%, the measured work function was 4.2eV that is suitable for NMOS gate. To identify interface stability between Ta-Mo alloy metal and $SiO_2$, C-V, FE-SEM(Field Emission-SEM), and XRD(X-ray diffraction) were performed on the samples annealed with rapid thermal processor between $600^{\circ}C$ and $900^{\circ}C$. Even after $900^{\circ}C$ rapid thermal annealing, excellent interface stability and electrical properties were observed. Also, thermodynamic analysis was studied to compare with experimental results.

• Journal of the Korean Magnetics Society
• /
• v.5 no.5
• /
• pp.483-486
• /
• 1995

Soft magnetic properties of Fe-based (Fe,Co)-B-Al-M (M=Nb, Mo or Ta) nanocrystalline alloy have been investigated. The alloy obtained directly form the rapid solidification process. Microstructure of the alloy is a mixtu re of ultrafine bcc Fe(Co) nanocrystallines and a small amount of retained amorphous phase. Heat treatment of as-prepared alloys improves soft magnetic properties in high frequency range. ${(Fe_{.85}Co_{.15})}_{70}B_{18}Al_{10}Ta_{6}$ alloy alloy annealed at $500^{\circ}C$ for 1 h shows the most improved soth magnetic properties among the alloy examined. Average grain size of the nanocystalline is about 10 nm.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2006.06a
• /
• pp.122-124
• /
• 2006

Ta-Mo를 co-sputtering으로 증착하여 MOS-C(Capacitor)를 제작하였다. 열적 화학적 안정성을 판별하기 위해 $600^{\circ}C$, $700^{\circ}C$, $800^{\circ}C$ 에서 급속 열처리를 행하였고, C-V 측정으로 얻은 데이터로 평탄 전압, 일함수, EOT값을 계산 하였다. I-V 측정으로 누설 전류 특성을 파악 하였다. 위의 실험 데이터를 종합하여 폴리 실리콘 게이트를 대체할 차세대 게이트 물질로써 Ta-Mo 게이트 물질을 제안하였다.

• Journal of Powder Materials
• /
• v.10 no.3
• /
• pp.164-167
• /
• 2003

The mechanical alloying effect has been studied on the three Cu-based alloy systems with a positive heat of mixing. The extended bcc solid solution has been formed in the Cu-V system and an amorphous phase in the Cu-Ta system. However, it is round that a mixture of nanocrystalline Cu and Mo Is formed in the Cu-Mo system. The neutron diffraction has been employed at a main tool to characterize the detailed amorphization process. The formation of an amorphous phase in Cu-Ta system can be understood by assuming that the smaller Cu atoms preferentially enter into the bcc Ta lattice during ball milling.

• Archives of Metallurgy and Materials
• /
• v.65 no.4
• /
• pp.1311-1315
• /
• 2020

This study investigates the microstructures and the mechanical properties of equiatomic Ti₂₀Mo₂₀Ta₂₀Nb₂₀V₂₀ and non-equiatomic Ti₄₀Mo₁₅Ta₁₅Nb₁₅V₁₅ and Ti₆₀Mo₁₀Ta₁₀Nb₁₀V₁₀ HEAs using X-ray diffraction (XRD) analysis, field emission scanning electron microscope (FE-SEM), and micro-Vickers hardness test. The specimens were fabricated using the vacuum arc remelting (VAR) process and homogenized at a temperature of 1300℃ for 4 h in a vacuum atmosphere. The determined thermodynamic parameters, Ω ≥ 1.1, δ ≤ 6.6%, and VEC < 6.87, suggested that the HEAs consisted of BCC solid solutions. XRD patterns of all the HEAs displayed single BCC phases. The difference in the solidification rate led to the micro-segregation associated with the elements Ta and Mo enriched in the dendrite arms and the elements V and Ti in the inter-dendritic regions. The HEA specimens showed a decrease in hardness with higher concentration of Ti element because the intrinsic hardness of Ti is lower as compared to the intrinsic hardness of Nb and Mo.

• Archives of Metallurgy and Materials
• /
• v.65 no.4
• /
• pp.1269-1272
• /
• 2020

In this study, a molybdenum alloy with dispersed high-entropy particles was fabricated using the powder metallurgy method. The high-entropy powder, composed of Nb, Ta, V, W, and Zr elements with a same atomic fraction, was prepared via high-energy ball milling. Using this powder, an ideal core-shell powder, composed of high-entropy powder as core and Mo powder as shell, was synthesized via the milling and reduction processes. These processes enabled the realization of an ideal microstructure with the high-entropy phase uniformly dispersed in the Mo matrix. The sintered body was successfully fabricated via uniaxial compaction followed by pressureless sintering. The sintered body was analyzed by X-ray diffraction and scanning electron microscope, and the high-entropy phase is uniformly dispersed in the Mo matrix.

• Journal of Powder Materials
• /
• v.6 no.4
• /
• pp.314-319
• /
• 1999

The solid state reaction by mechanical alloying(MA) generally proceeds by lowering the free energy as the result of a chemical reaction at the interface between the two adjacent layers. However, Lee et $al.^{1-5)}$ reported that a mixture of Cu and Ta, the combination of which is characterized by a positive heat of mixing of +2kJ/mol, could be amorphized by mechanical alloying. This implies that there exists an up-hill process to raise the free energy of a mixture of pure Cu and la to that of an amorphous phase. It is our aim to investigate to what extent the MA is capable of producing a non-equilibrium phase with increasing the heat of mixing. The system chosen was the ternary $Cu_{30}Ta_{ 70-x}Mo_ x$ (x=35, 10). The mechanical alloying was carried out using a Fritsch P-5 planetary mill under Ar gas atmosphere. The MA powders were characterized by the X-ray diffraction with Cu-K $\alpha$ radiation, thermal analysis, electron diffraction and TEM micrographs. In the case of x=35, where pure Cu powders were mixed with equal amount of pure Ta and Mo powders, we revealed the formation of bcc solid solution after 150 h milling but its gradual decomposition by releasing fcc-Cu when milling time exceeded 200 h. However, an amorphous phase was clearly formed when the Mo content was lowered to x=10. It is believed that the amorphization of ternary $Cu_{30}Ta_{60}Mo_{10}$ powders is essentially identical to the solid state amorphization process in binary $Cu_{30}Ta_{70}$ powders.