• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.546-546
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• 2008

Copper (Cu) Chemical mechanical polishing (CMP) has been an essential process for Cu wifing of DRAM and NAND flash memory beyond 45nm. Copper has been employed as ideal material for interconnect and metal line due to the low resistivity and high resistant to electro-migration. Damascene process is currently used in conjunction with CMP in the fabrication of multi-level copper interconnects for advanced logic and memory devices. Cu CMP involves removal of material by the combination of chemical and mechanical action. Chemicals in slurry aid in material removal by modifying the surface film while abrasion between the particles, pad, and the modified film facilitates mechanical removal. In our research, we emphasized on the role of chemical effect of slurry on Cu CMP, especially on the effect of amine functional group on removal rate selectivity between Cu and Tantalum-nitride (TaN) film. We investigated the two different kinds of complexing agent both with amine functional group. On the one hand, Polyacrylamide as a polymer affected the stability of abrasive, viscosity of slurry and the corrosion current of copper film especially at high concentration. At higher concentration, the aggregation of abrasive particles was suppressed by the steric effect of PAM, thus showed higher fraction of small particle distribution. It also showed a fluctuation behavior of the viscosity of slurry at high shear rate due to transformation of polymer chain. Also, because of forming thick passivation layer on the surface of Cu film, the diffusion of oxidant to the Cu surface was inhibited; therefore, the corrosion current with 0.7wt% PAM was smaller than that without PAM. the polishing rate of Cu film slightly increased up to 0.3wt%, then decreased with increasing of PAM concentration. On the contrary, the polishing rate of TaN film was strongly suppressed and saturated with increasing of PAM concentration at 0.3wt%. We also studied the electrostatic interaction between abrasive particle and Cu/TaN film with different PAM concentration. On the other hand, amino-methyl-propanol (AMP) as a single molecule does not affect the stability, rheological and corrosion behavior of the slurry as the polymer PAM. The polishing behavior of TaN film and selectivity with AMP appeared the similar trend to the slurry with PAM. The polishing behavior of Cu film with AMP, however, was quite different with that of PAM. We assume this difference was originated from different compactness of surface passivation layer on the Cu film under the same concentration due to the different molecular weight of PAM and AMP.

• Journal of Adhesion and Interface
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• v.21 no.3
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• pp.107-112
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• 2020

Recently, the atomically thin transition-metal dichalcogenide (TMD) semiconductors have attracted much attention owing to their remarkable properties such as tunable bandgap with high carrier mobility, flexibility, transparency, etc. However, because these TMD materials have a significant drawback that they are easily degraded in an ambient environment, various attempts have been made to improve chemical stability. In this research article, I report a method to improve the air stability of WSe₂ one of the TMD materials via surface passivation with an h-BN insulator, and its application to field-effect transistors (FETs). With a modified hot pick-up transfer technique, a vertical heterostructure of h-BN/WSe₂ was successfully made, and then the structure was used to fabricate the top-gate bottom-contact FETs. The fabricated WSe₂-based FET exhibited not only excellent air stability, but also high hole mobility of 150 ㎠/Vs at room temperature, on/off current ratios up to 3×10⁶, and 192 mV/decade of subthreshold swing.

• Journal of the Korean Society of Industry Convergence
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• v.7 no.3
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• pp.259-263
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• 2004

In the manufacture progress of LCD or semiconductor, there are used many kinds of gas like erosion gas, dilution gas, toxic gas as a progress which used these gas there are required high puritize to increase accumulation rate of semiconductor or LCD materials work progress of semiconductor or LCD it demand many things like the material which could minimize metallic dust that could be occured by reaction between gas and transfer pipe laying material, illumination of the surface, emition of the gas, metal liquation, welding etc also demand quality geting stricted. Material-Low-sulfur-contend (0.007-0010), vacuum-arc-remelt(VAR), seamless, high-purity tubing material is recommend for enhance welding lower surface defect density All wetted stainless steel surface must be 316LSS elecrto polishinged with ${\leq}0.254{\mu}m$($10.0{\mu}in$) Ra average surface finish, $Cr/Fe{\geq}1.1$ and $Cr_2O_3$ thickness ${\geq}25{\AA}$ From the AES analytical the oxide layer thickness (23.5~36 angstroms silicon dioxide equivalent) and chromum to iron ratios is similar to those generally found on electropolished stainless steel., molybdenum and silicon contaminants ; elements characteristic of stainless steel (iron, nickel and chromium); and oxygen were found on the surface Phosphorus and nitrogen are common contaminants from the electropolish and passivation steps.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.105-105
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• 2012

We have developed a photoemission-assisted plasma-enhanced chemical vapor deposition (PAPE-CVD) [1,2], in which photoelectrons emitting from the substrate surface irradiated with UV light ($h{\nu}$=7.2 eV) from a Xe excimer lamp are utilized as a trigger for generating DC discharge plasma as depicted in Fig. 1. As a result, photoemission-assisted plasma can appear just above the substrate surface with a limited interval between the substrate and the electrode (~10 mm), enabling us to suppress effectively the unintended deposition of soot on the chamber walls, to increase the deposition rate, and to decrease drastically the electric power consumption. In case of the deposition of DLC gate insulator films for the top-gate graphene channel FET, plasma discharge power is reduced down to as low as 0.01W, giving rise to decrease significantly the plasma-induced damage on the graphene channel [3]. In addition, DLC thickness can be precisely controlled in an atomic scale and dielectric constant is also changed from low ${\kappa}$ for the passivation layer to high ${\kappa}$ for the gate insulator. On the other hand, negative electron affinity (NEA) of a hydrogen-terminated diamond surface is attractive and of practical importance for PAPECVD, because the diamond surface under PAPE-CVD with H2-diluted (about 1%) CH4 gas is exposed to a lot of hydrogen radicals and therefore can perform as a high-efficiency electron emitter due to NEA. In fact, we observed a large change of discharge current between with and without hydrogen termination. It is noted that photoelectrons are emitted from the SiO2 (350 nm)/Si interface with 7.2-eV UV light, making it possible to grow few-layer graphene on the thick SiO2 surface with no transition layer of amorphous carbon by means of PAPE-CVD without any metal catalyst.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.2
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• pp.179-184
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• 2016

In recent years, the on-resistance, power loss and cell density of Si power devices have not exhibited significant improvements, and performance is approaching the material limits. GaN is considered an attractive material for future high-power applications because of the wide band-gap, large breakdown field, high electron mobility, high switching speed and low on-resistance. Here we report on the Ohmic contact resistance and reverse-bias characteristics of AlGaN/GaN Schottky barrier diodes with and without annealing. Annealing in oxygen at $500^{\circ}C$ resulted in an increase in the breakdown voltage from 641 to 1,172 V for devices with an anode-cathode separation of $20{\mu}m$. However, these annealing conditions also resulted in an increase in the contact resistance of $0.183{\Omega}-mm$, which is attributed to oxidation of the metal contacts. Auger electron spectroscopy revealed diffusion of oxygen and Au into the AlGaN and GaN layers following annealing. The improved reverse-bias characteristics following annealing in oxygen are attributed to passivation of dangling bonds and plasma damage due to interactions between oxygen and GaN/AlGaN. Thermal annealing is therefore useful during the fabrication of high-voltage GaN devices, but the effects on the Ohmic contact resistance should be considered.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.39 no.1
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• pp.22-30
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• 2002

The nucleation of copper(Cu) with (hfac)iu(VTMS) oganometallic precursor is investigated for Si, $Sio_2$, TiN, $W_2N$ substrates. As the deposition temperature is increased, the dominant growth mechanism is observed to change from the nucleation of Cu particles to the clustering of Cu nuclei around $180^{\ciec}C$, independent of the employed substrates. It is also observed that the cleaning of substrate surfaces with the diluted HF solution improves the selectivity of Cu nucleation between TiN and $Sio_2$ substrates. Dimethyldichlorosilane treatment is found to passivate the surface of TiN substrate, contrary to the generally accepted belief, when the TiN substrate is cleaned by $H_2O_2$ solution before the treatment.

• Electrical & Electronic Materials
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• v.9 no.5
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• pp.463-469
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• 1996

The double insulating layer consisting of anodic oxide and ZnS was formed for HgCdTe metal insulator semiconductor(MIS) structure. ZnS was evaporated on the anodic oxide grown in H$_{2}$O$_{2}$ electrolyte. Recently, this insulating mechanism for HgCdTe MIS has been deeply studied for improving HgCdTe surface passivation. It was found through TEM observation that an interface layer is formed between ZnS and anodic oxide layers for the first time in the study of this area. EDS analysis of chemical compositions using by electron beam of 20.angs. in diameter and XPS depth composition profile indicated strongly that the new interface is composed of ZnO. Also TEM high resolution image showed that the structure of oxide layer has been changed from the amorphous state to the microsrystalline structure of 100.angs. in diameter after the evaporation of ZnS. The double insulating layer with the resistivity of 10$^{10}$ .ohm.cm was estimated to be proper insulating layer of HgCdTe MIS device. The optical reflectance of about 7% in the region of 5.mu.m showed anti-reflection effect of the insulating layer. The measured C-V curve showed the large shoft of flat band voltage due to the high density of fixed oxide charges about 1.2*10$^{12}$ /cm$^{2}$. The oxygen vacancies and possible cationic state of Zn in the anodic oxide layer are estimated to cause this high density of fixed oxide charges.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.376.2-376.2
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• 2014

마이크로볼로미터 적외선 센서는 인체감지, 전자부품의 품질검사, 에너지 절감, 산업시설감시 및 군사용으로 다양하게 적용되고 있다. 기존에 이러한 적외선 센서의 감지재료로 VOx 또는 비정질 Si이 가장 많이 사용되고 있으며, VOx는 감도가 높고, 세계적으로 가장 많이 사용되고 있는 물질이다. 본 연구에서는 기존의 VOx 박막 증착법을 개선하여 Zn 산화물 박막을 혼용한 적외선 감지재료를 이용한 마이크로볼로미터 제작 및 특성에 대해 보고한다. RF sputtering 방법으로 약 140 nm의 VOx/ZnO/VOx 샌드위치 박막을 증착하고, 산소분위기에서 열처리함으로써 온도저항계수(TCR)가 약 -3.0 %/K의 값을 갖는 특성을 구현하였다. 갓 증착된 V-Zn 박막에서는 XRD 스펙트럼에서는 V2O5 관련 피크가 주로 관측되었으며, 산소열처리에 의해 VO2 피크가 새롭게 관측되었다. 볼로미터 감지소자는 유효면적 $50{\times}50{\mu}m^2$ 으로 bulk micromaching 공정을 통해 제작하였다. Si 기판위에 SiNx 박막을 PECVD 장치를 이용하여 증착하였으며, 적외선 감지층으로 V-Zn 산화물을 RF sputtering 방법으로 증착하여 열처리 후 SiNx passivation 박막으로 보호하였다. 열적고립을 위해 패터닝 후 Si 기판을 KOH 용액을 이용하여 약 $20{\mu}m$ 식각하여 소자를 구현하였다. 제작된 소자의 특성을 평가한 결과 반응도는 1.57e+4 V/W, 탐지도는 $8.79e+7cmHz^{1/2}/W$를 얻을 수 있었다. 소자의 동작 특성을 평가하기 위해 진공 압력을 1e-3 torr 이하에서 thermoelectric cooler를 장착한 metal package를 제작하여 동작온도에 따른 특성을 평가하였다. 동작온도를 $10^{\circ}C{\sim}40^{\circ}C$로 하여 측정한 결과 동작온도가 증가할수록 신호전압은 감소함을 알 수 있었다.

• Current Photovoltaic Research
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• v.1 no.1
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• pp.17-26
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• 2013

In contrast to conventional crystalline cells, back-contact solar cells feature high efficiencies, simpler module assembly, and better aesthetics. The highest commercialized cell and module efficiency was recorded by n-type back-contact solar cells. However, the mainstream PV industry uses a p-type substrate instead of n-type due to the high costs and complexity of the manufacturing processes in the case of the latter. P-type back-contact solar cells such as metal wrap-through and emitter wrap-through, which are inexpensive and compatible with the current PV industry, have consequently been developed. In this paper the characteristics of EWT (emitter wrap-through) solar cells and their status and prospects for development are discussed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.117-117
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• 2008

In MIM capacitor, poly-Si bottom electrode is replaced with metal bottom electrode. Noble metals can be used as bottom electrodes of capacitors because they have high work function and remain conductive in highly oxidizing conditions. In addition, they are chemically very stable. Among novel metals, Ru (ruthenium) has been suggested as an alternative bottom electrode due to its excellent electrical performance, including a low leakage of current and compatibility to high dielectric constant materials. Chemical mechanical planarization (CMP) process has been suggested to planarize and isolate the bottom electrode. Even though there is a great need for development of Ru CMP slurry, few studies have been carried out due to noble properties of Ru against chemicals. In the organic chemistry literature, periodate ion ($IO_4^-$) is a well-known oxidant. It has been reported that sodium periodate ($NaIO_4$) can form $RuO_4$ from hydrated ruthenic oxide ($RuO_2{\cdot}nH_2O$). $NaIO_4$ exist as various species in an aqueous solution as a function of pH. Also, the removal mechanism of Ru depends on solution of pH. In this research, the static etch rate, passivation film thickness and wettability were measured as a function of slurry pH. The electrochemical analysis was investigated as a function of pH. To evaluate the effect of pH on polishing behavior, removal rate was investigated as a function of pH by using patterned and unpatterned wafers.