• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.97-98
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• 2009

Tunneling barrier engineered charge trap flash (TBE-CTF) memory capacitor were fabricated using the tunneling barrier engineering technique. Variable oxide thickness (VARIOT) barrier and CRESTED barrier consisting of thin $SiO_2$ and $Si_3N_4$ dielectrics layers were used as engineered tunneling barrier. The charge trapping characteristic with different metal gates are also investigated. A larger memory window was achieved from the TBE-CTF memory with high workfunction metal gate.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.344-344
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• 2010

A capacitor with engineered tunnel barrier composed of High-k materials has been fabricated. Variable oxide thickness (VARIOT) barrier consisting of thin SiO2/HfO2/Al2O3 (2/1/3 nm) dielectric layers were used as engineered tunneling barrier. We studied the electrical characteristics of multi stacked tunnel layers for various RTA (Rapid Thermal Anneal) and FGA (Forming Gas Anneal) temperature.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.22 no.2
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• pp.105-115
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• 2024

In this study, we employed a small-scale experiment to demonstrate the introduction of a thin copper heat dissipation plate into a bentonite buffer layer of an engineered barrier system. This experiment designed for spent nuclear fuel disposal can effectively reduce the maximum temperature of the bentonite buffer layer, and ultimately, make it possible to reduce the area of the disposal site. For the experiment, a small-scale engineered barrier system with a copper heat dissipation plate was designed and manufactured. the thickness of the cylindrical buffer was about 2 cm, which was about 1/20 of KAERI Repository System (KRS). At a power supply of 250 W, the maximum buffer temperature reduced to a mere 1.8℃ when the thin copper plate was introduced. However, the maximum surface temperature reduced to a remarkable 9.1℃, when a U-collar copper plate was introduced, which had a good contact with the other barrier layers. Consequently, we conclude that the introduction of the thin copper plate into the engineered barrier system for spent nuclear fuel disposal can effectively reduce the maximum buffer temperature in high-level radioactive waste disposal repositories.

• Nuclear Engineering and Technology
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• v.54 no.11
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• pp.4005-4012
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• 2022

As high-level radioactive waste (HLW) generated from nuclear power plants is harmful to the human body, it must be safely disposed of by an engineered barrier system consisting of disposal canisters and buffer and backfill materials. A gap exists between the canister and buffer material in a HLW repository and between the buffer material and natural rock-this gap may reduce the water-blocking ability and heat transfer efficiency of the engineered barrier materials. Herein, the basic characteristics and thermal properties of granular bentonite, a candidate gap-filling material, were investigated, and their effects on the temperature change of the buffer material were analyzed numerically. Heat transfer by air conduction and convection in the gap were considered simultaneously. Moreover, by applying the Korean reference disposal system, changes in the properties of the buffer material were derived, and the basic design of the engineered barrier system was presented according to the gap filling material (GFM). The findings showed that a GFM with high initial thermal conductivity must be filled in the space between the buffer material and rock. Moreover, the target dry density of the buffer material varied according to the initial wet density, specific gravity, and water content values of the GFM.

• Tunnel and Underground Space
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• v.17 no.6
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• pp.464-474
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• 2007

An enhancement in the performance and safety of a high-level waste repository requires a validation of its engineered barrier. An engineering-scale test (named "KENTEX") has been conducted to investigate the thermal-hydro-mechanical behaviors in the engineered barrier of the Korean reference disposal system The validation test started on May 31, 2005 and is still under operation. The experimental data obtained allowed a preliminary and qualitative interpretation of the thermal-hydro-mechanical behaviors in the bentonite blocks. The temperature was higher as it became closer to the heater, while it became lower as it was farther away from the heater. The water content had a higher value in the part close to the hydration surface than that in the heater part. The relative humidity data suggested that a hydration of the bentonite blocks might occur by different drying-wetting processes, depending on their position. The total pressure was continuously increased by the evolution of the saturation front in the bentonite blocks and thereby the swelling pressure. Near the heater region, there was also a significant contribution of the thermal expansion of bentonite and the vapor pressure in the pores of the bentonite blocks.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.56-56
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• 2009

In this study, we fabricated the engineered $SiO_2/Si_3N_4/SiO_2$(ONO) tunnel barrier with high-k $HfO_2$ trapping layer for application high performance flash MLC(Multi Level Cell). As a result, memory device show low operation voltage and stable memory characteristics with large memory window. Therefore, the engineered tunnel barrier with ONO stacks were useful structure would be effective method for high-integrated MLC memory applications.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.1
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• pp.17-21
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• 2009

The electrical characteristics of band-gap engineered tunneling barriers consisting of thin $SiO_2$ and $Si_3N_4$ dielectric layers were investigated for nonvolatile memory device applications. The band structure of band-gap engineered tunneling barriers was studied and the effectiveness of these tunneling barriers was compared with the conventional tunneling $SiO_2$ barrier. The band-gap engineered tunneling barriers composed of thin $SiO_2$ and $Si_3N_4$ layers showed a lower operation voltage, faster speed and longer retention time than the conventional $SiO_2$ tunnel barrier. The thickness of each $SiO_2$ and $Si_3N_4$ layer was optimized to improve the performance of non-volatile memory.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.133-133
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• 2009

It is desirable to choose a high-k material having a large band offset with the tunneling oxide and a deep trapping level for use as the charge trapping layer to achieve high PIE (Programming/erasing) speeds and good reliability, respectively. In this paper, charge trapping and tunneling characteristics of high-k hafnium oxide ($HfO_2$) layer with various thicknesses were investigated for applications of tunnel barrier engineered nonvolatile memory. A critical thickness of $HfO_2$ layer for suppressing the charge trapping and enhancing the tunneling sensitivity of tunnel barrier were developed. Also, the charge trap centroid and charge trap density were extracted by constant current stress (CCS) method. As a result, the optimization of $HfO_2$ thickness considerably improved the performances of non-volatile memory(NVM).

• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.192-192
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• 1998

The blood - brain barrier (BBB) expresses high concentrations of transferrin receptor, and it was revealed that anti-transferrin receptor mouse monoclonal antibody (OX26) undergoes transcytosis through the BBB. This property allows the OX26 to serve as a brain drug delivery vector. In an attempt to produce broadly useful targeting agents, genetic engineering and expression techniques have been used to produce antibody-avidin (AV) fusion protein (OX26 IgG3C$\_$H/3-AV). In the present study we estimated the BBB permeability and stability of genetically engineered vector.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.7-8
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• 2008

The memory characteristics of charge trap flash (CTF) with $HfO_2$ charge trap layer were investigated. Especially, we focused on the effects of tunnel barrier engineering consisted of $SiO_2/Si_3N_4/SiO_2$ (ONO) stack or $Si_3N_4/SiO_2/Si_3N_4$ (NON) stack. The programming and erasing characteristics were significantly enhanced by using ONO or NON tunnel barrier. These improvement are due to the increase of tunneling current by using engineered tunnel barrier. As a result, the engineered tunnel barrier is a promising technique for non-volatile flash memory applications.