• Korean Journal of Materials Research
• /
• v.9 no.8
• /
• pp.831-836
• /
• 1999

Magnetic properties of (Fe(sub)1-xCo(sub)x)(sub)89Zr11 amorphous films fabricated by RF sputtering method have been investigated as a function of Co content x. By means of two step field annealing at 190~20$0^{\circ}C$ for 10 minutes in the magnetic field of 130 Oe, the film with x=0.4 among the samples shows the superior soft magnetic properties in spite of showing the high magnetostriction. For example, the obtained properties of coercivity and differential permeability measured in an exciting field of 10 mOe at the frequency of 8.7 MHz are 0.25 Oe and 280, respectively. It is confirmed that such behavior is due to the variation of magnetic anisotropies caused by a optimal compressive stress within the film.

• Applied Microscopy
• /
• v.43 no.4
• /
• pp.173-176
• /
• 2013

The oxidation behavior of the crystallized $Al_{87}Ni_3Y_{10}$ alloy has been investigated with an aim to compare with that of the amorphous $Al_{87}Ni_3Y_{10}$ alloy. The oxidation at 873 K occurs as follows: (1) growth of an amorphous aluminum-yttrium oxide layer (~10 nm) after heating up to 873 K; and (2) formation of $YAlO_3$ crystalline oxide (~220 nm) after annealing for 30 hours at 873 K. Such an overall oxidation step indicates that the oxidation behavior in the crystallized $Al_{87}Ni_3Y_{10}$ alloy occurs in the same way as in the amorphous $Al_{87}Ni_3Y_{10}$ alloy. The simultaneous presence of aluminum and yttrium in the oxide layer significantly enhances the thermal stability of the amorphous structure in the oxide phase. Since the structure of aluminum-yttrium oxide is dense due to the large difference in ionic radius between aluminum and yttrium ions, the diffusion of oxygen ion through the amorphous oxide layer is limited thus stabilizing the amorphous structure of the oxide phase.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.04a
• /
• pp.46-49
• /
• 2002

The aim of this paper is to investigate the influence of various deformation ratio on texture of Ag tapes that can be used as a RE-$Ba_2Cu_3O_{7-{\delta}}$ coated conductor tapes without any buffer layer. We fabricated as-rolled Ag substrate with various deformation ratio per step. Thickness and total deformation ratio of Ag tapes were $100{\mu}m$ and >98%, respectively. And as-rolled Ag substrate was annealed at $750^{\circ}C$ for 30min. The as-rolled and recrystallization textures were measured using x-ray pole figures and orientation distribution function (ODF) analysis. With the increase of rolling ratio from 5 to 20%, deformation texture are changed from {1l0}<311> to {1l0}<112>, {032}<100>, {051}<211>. After recrystallization by annealing, main texture was observed to {013}<100> under present condition.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.19 no.5
• /
• pp.457-460
• /
• 2006

Y doped zinc oxide (YZO) thin films were deposited on F doped $SnO_2$ (FTO) glass substrate by sol-gel method using the spin-coating system. A homogeneous and stable solution was prepared by dissolving acetate in the solution added diethanolamine as sol-gel stabilizer. YZO films were obtained after preheated on the hot-plate for 5minute before each coating; the number of coating was 3 times. After the coating of last step, annealing of YZO films performed at $450^{\circ}C$ for 30 minute. In order to confirming of a ultraviolet ray interruption and down-conversion effects, optical properties of YZO films, transmission spectrum and fluorescent spectrum were used. Also, for understanding the obtained results by experiment, the elestronic state of YZO was calculated using the density functional theory The results obtained by experiment were compared with calculated structure. The detail of electronic structure was obtained by the discrete variational Xa (DV-Xa) method, which is a sort of molecular orbital full potential method. The density of state and energy levels of dopant element were shown and discussed in association with optical properties.

• Bulletin of the Korean Chemical Society
• /
• v.22 no.2
• /
• pp.213-218
• /
• 2001

Presented are the STM images of self-assembled monolayer of 2-mercaptoethanol on Au(111). Striped structures of ($6{\times}3_{\frac{1}{2}}$), ($5{\times}3_{\frac{1}{2}}$), ($4{\times}3_{\frac{1}{2}}$) and compact-($5{\times}3_{\frac{1}{2}}$) were observed after annealing at $80^{\circ}C.$ Analysis of the ordered structures revealed that the basic fundamental units of the ordered structures were three crystallographically non-equivalent ($3_{\frac{1}{2}}{\times}3_{\frac{1}{2}}$) $R30^{\circ}$ assemblies, and that the way of combination of the assemblies produced the four different structures. The($6{\times}3_{\frac{1}{2}}$) structure ( $\theta$ = 0.33) was composed of one ($3_{\frac{1}{2}}{\times}3_{\frac{1}{2}}$)$R30^{\circ}$ assembly, while the ($5{\times}3_{\frac{1}{2}}$) ( $\theta$ = 0.30) and ($4{\times}3_{\frac{1}{2}}$) ( $\theta$ = 0.38) structures were consisted of two ($3_{\frac{1}{2}}{\times}3_{\frac{1}{2}}$) $R30^{\circ}$ assemblies, separated by 5a and 4a, respectively. Furthermore, the compact-(5X 3½) structure ( $\theta$ = 0.50) was obtained by overlapping three ($3_{\frac{1}{2}}{\times}3_{\frac{1}{2}}$) $R30^{\circ}$ assemblies. In spite of the diversity in the adsorption structures, all the adsorption sites of 2-mercaptoethanol were fundamentally identical. On the other hand, the unannealed primitive SAM of 2-mercaptoethanol was characterized by two observations: a short-range order keeping the adsorbed molecules at approximately $3_{\frac{1}{2}}$ a and the small domains of the striped structures supporting that the observed surface structures on the annealed surface were the extension of the primitive layer of 2-mercaptoethanol. Comparing these observations with the already published structures of ethanthiol, it was concluded that the interaction between the hydroxyl groups of 2-mercaptoethanol might play a significant role in the adsorption step of 2-mercaptoethanol on Au(111) to organize the adsorption structures different from those of ethanthiol.

• Korean Journal of Materials Research
• /
• v.26 no.8
• /
• pp.430-437
• /
• 2016

Aluminum oxide ($Al_2O_3$) thin films were grown by atomic layer deposition (ALD) using a new Al metalorganic precursor, dimethyl aluminum sec-butoxide ($C_{12}H_{30}Al_2O_2$), and water vapor ($H_2O$) as the reactant at deposition temperatures ranging from 150 to $300^{\circ}C$. The ALD process showed typical self-limited film growth with precursor and reactant pulsing time at $250^{\circ}C$; the growth rate was 0.095 nm/cycle, with no incubation cycle. This is relatively lower and more controllable than the growth rate in the typical $ALD-Al_2O_3$ process, which uses trimethyl aluminum (TMA) and shows a growth rate of 0.11 nm/cycle. The as-deposited $ALD-Al_2O_3$ film was amorphous; X-ray diffraction and transmission electron microscopy confirmed that its amorphous state was maintained even after annealing at $1000^{\circ}C$. The refractive index of the $ALD-Al_2O_3$ films ranged from 1.45 to 1.67; these values were dependent on the deposition temperature. X-ray photoelectron spectroscopy showed that the $ALD-Al_2O_3$ films deposited at $250^{\circ}C$ were stoichiometric, with no carbon impurity. The step coverage of the $ALD-Al_2O_3$ film was perfect, at approximately 100%, at the dual trench structure, with an aspect ratio of approximately 6.3 (top opening size of 40 nm). With capacitance-voltage measurements of the $Al/ALD-Al_2O_3/p-Si$ structure, the dielectric constant of the $ALD-Al_2O_3$ films deposited at $250^{\circ}C$ was determined to be ~8.1, with a leakage current density on the order of $10^{-8}A/cm^2$ at 1 V.

• Current Photovoltaic Research
• /
• v.3 no.3
• /
• pp.85-90
• /
• 2015

Two-step processes for preparing $Cu(In,Ga)Se_2$ absorber layers consist of precursor layer formation and subsequent annealing in a Se-containing atmosphere. Among the various deposition methods for precursor layer, the nonvacuum (wet) processes have been spotlighted as alternatives to vacuum-based methods due to their potential to realize low-cost, scalable PV devices. However, due to its porous nature, the precursor layer deposited on Mo substrate by nonvacuum methods often suffers from thick $MoSe_2$ formation during selenization under a high Se vapor pressure. On the contrary, selenization under a low Se pressure to avoid $MoSe_2$ formation typically leads to low crystal quality of absorber films. Although TiN has been reported as a diffusion barrier against Se, the additional sputtering to deposit TiN layer may induce the complexity of fabrication process and nullify the advantages of nonvacuum deposition of absorber film. In this work, Mo oxide layers via thermal oxidation of Mo substrate have been explored as an alternative diffusion barrier. The morphology and phase evolution was examined as a function of oxidation temperature. The resulting Mo/Mo oxides double layers were employed as a back contact electrode for $CuInSe_2$ solar cells and were found to effectively suppress the formation of $MoSe_2$ layer.

• Applied Chemistry for Engineering
• /
• v.26 no.3
• /
• pp.251-258
• /
• 2015

In the study, PLLA with 12,000 g/mol ($M_n$) and 14,000 g/mol ($M_w$) was synthesized from L-lactide, and used to synthesize PLLA-Br intermediate. PLLA-block-PMMA with 84,000 g/mol ($M_n$) and 126,000 g/mol ($M_w$) was finally synthesized from PLLA-Br intermediate. The glass transition temperature ($T_g$) and initial pyrolysis temperature of PLLA-block-PMMA are $95.5^{\circ}C$ and $289^{\circ}C$, respectively. The PLA film of $50{\pm}3{\mu}m$ thickness was prepared by blending PLA with 9 phr PLLA-block-PMMA followed by stretching biaxially at 3 times under $95^{\circ}C$, and annealing at $120^{\circ}C$ for 2 min. The light transmittance at 550 nm and tensile strength of the film are 88.5% and 44.5 MPa, respectively. To enhance the tensile strength of PLA film, it was required to keep the film more than 2 min at $120^{\circ}C$ during the annealing step after a biaxially orientation.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.02a
• /
• pp.229-229
• /
• 2010

With the scaling down of ultra large integrated circuits (ULSI) to the sub-50 nm technology node, the need for an ultra-thin, continuous and conformal diffusion barrier and Cu seed layer is increasing. However, diffusion barrier and Cu seed layer formation with a physical vapor deposition (PVD) method has become difficult as the technology node is reduced to 30 nm and beyond. Recent work on self-forming barrier processes using PVD Cu alloys have attracted great attention due to the capability of conformal ultra-thin barrier formation using a simple technique. However, as in the case of the conventional barrier and Cu seed layer, PVD of the Cu alloy seed layer will eventually encounter the difficulty in conformal deposition in narrow line trenches and via holes. Atomic layer deposition (ALD) has been known for its good step coverage and precise thickness control, and is a candidate technique for the formation of a thin conformal barrier layer and Cu seed layer. Conformal Cu-Mn seed layers were deposited by plasma enhanced atomic layer deposition (PEALD) at low temperature ($120^{\circ}C$), and the Mn content in the Cu-Mn alloys were controlled form 0 to approximately 10 atomic percent with various Mn precursor feeding times. Resistivity of the Cu-Mn alloy films decreased by annealing due to out-diffusion of Mn atoms. Out-diffused Mn atoms were segregated to the surface of the film and interface between a Cu-Mn alloy and $SiO_2$, resulting in self-formed $MnO_x$ and $MnSi_xO_y$, respectively. No inter-diffusion was observed between Cu and $SiO_2$ after annealing at $500^{\circ}C$ for 12 h, indicating an excellent diffusion barrier property of the $MnSi_xO_y$. The adhesion between Cu and $SiO_2$ was enhanced by the formation of $MnSi_xO_y$. Continuous and conductive Cu-Mn seed layers were deposited with PEALD into 32 nm $SiO_2$ trench, enabling a low temperature process, and the trench was perfectly filled using electrochemical plating (ECD) under conventional conditions. Thus, it is the resultant self-forming barrier process with PEALD Cu-Mn alloy film as a seed layer for plating Cu that has further potential to meet the requirement of the smaller than 30 nm node.

• Korean Journal of Materials Research
• /
• v.21 no.2
• /
• pp.78-82
• /
• 2011

Mono- and few-layer graphenes were grown on Ni thin films by rapid-thermal pulse chemical vapor deposition technique. In the growth steps, the exposure step for 60 s in $H_2$ (a flow rate of 10 sccm (standard cubic centimeters per minute)) atmosphere after graphene growth was specially established to improve the quality of the graphenes. The graphene films grown by exposure alone without $H_2$ showed an intensity ratio of $I_G/I_{2D}$ = 0.47, compared with a value of 0.38 in the films grown by exposure in H2 ambient. The quality of the graphenes can be improved by exposure for 60 s in $H_2$ ambient after the growth of the graphene films. The physical properties of the graphene films were investigated for the graphene films grown on various Ni film thicknesses and on 260-nm thick Ni films annealed at 500 and $700^{\circ}C$. The graphene films grown on 260-nm thick Ni films at $900^{\circ}C$ showed the lowest $I_G/I_{2D}$ ratio, resulting in the fewest layers. The graphene films grown on Ni films annealed at $700^{\circ}C$ for 2 h showed a decrease of the number of layers. The graphene films were dependent on the thickness and the grain size of the Ni films.