• Electrical & Electronic Materials
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• v.8 no.4
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• pp.426-433
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• 1995

Effect of boron in GaAs have been investigated by photo induced current transient spectroscopy(PICTS). The starting material was undoped liquid encapsulated Czochralski(LEC) semi insulating GaAs and boron ion implantation at 150keV energy was conducted with dose of 10$\^$12/ and 10$\^$13/ions/cm$\^$2/. In ion implanted samples, the peaks related arsenic vacancy(V$\_$As/) were decreased but complex lattice defect was increased with annealing temperature. U band was observed at ion implanted(10$\^$13/ ions/cm$\^$2/) and thermally treated(550.deg. C) sample. More negative peak was detected after annealing at temperature between 600 and 700.deg. C. The measurement of dark current showed that the formation of B$\_$GA/-V$\_$As/, complex defect and complex lattice defect by ion implantation were a reasonable explanation for the decrease in dark current.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05b
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• pp.30-33
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• 2001

Chemical mechanical polishing(CMP) process has been widely used to planarize dielectrics, which can apply to employed in integrated circuits for sub-micron technology. Despite the increased use of CMP process, it is difficult to accomplish the global planarization of free-defects in inter-level dielectrics (ILD). Especially, defects like micro-scratch lead to severe circuit failure, and affects yield. CMP slurries can contain particles exceeding $1{\mu}m$ size, which could cause micro-scratch on the wafer surface. The large particles in these slurries may be caused by particle agglomeration in slurry supply line. To reduce these defects, slurry filtration method has been recommended in oxide CMP. In this work, we have studied the effects of filtration and the defect trend as a function of polished wafer count using various filters in inter-metal dielectric(IMD)-CMP. The filter installation in CMP polisher could reduce defect after IMD-CMP. As a result of micro-scratches formation, it shows that slurry filter plays an important role in determining consumable pad lifetime.

• Journal of Adhesion and Interface
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• v.21 no.2
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• pp.41-50
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• 2020

Organic-inorganic metal halide perovskite has shown a great promise in photovoltaic applications because of the skyrocketing power-conversion efficiencies up to 25.2% and their potentially low production cost. However, it also has critical issue of substantial material degradation during device operation to be overcome for successful commercialization. Understanding the nature of defects and their photochemistry related to material degradation is needed. Furthermore, strategy to passivate defects in perovskite should be adopted to improve the stability of perovskite. In this article, we present predominant defects formation in perovskite that contribute to material degradations in perovskite solar cells. We then discuss how material stability can be improved through reliable defect passivation engineering.

• Bulletin of the Korean Chemical Society
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• v.35 no.2
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• pp.353-356
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• 2014

We fabricated organic photovoltaic (OPV) based on ZnO ripple structure on indium tin oxide as electron-collecting layers and PTB7-F20 as donor polymer. In addition, atomic layer deposition (ALD) was used for preparing additional ZnO layers on rippled ZnO. Addition of 2 nm-thick ALD-ZnO resulted in enhanced initial OPV performance and stability. Based on photoluminescence results, we suggest that ALD-ZnO layers reduced number of surface defect sites on ZnO, which can act as electron-hole recombination center of OPV, and increased resistance of ZnO towards surface defect formation.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.26 no.3
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• pp.121-125
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• 2016

The effect of temperature and pressure in the nitrogen ambient furnace on bulk micro defect (BMD) and denuded zone (Dz) is experimentally investigated. It is found that as pressure increases, Dz depth increases with a small decrease of BMD density in the range of temperature, $100{\sim}300^{\circ}C$. BMD density with hot isostatic pressure treatment (HIP) at temperature of $850^{\circ}C$ is higher than that without HIP while Dz depth is lower due to much higher BMD density. As the pressure increases, BMD density is increased and saturated to a critical value, and Dz depth increases even if BMD density is saturated. The concentration of nitrogen increases near the surface with increasing pressure, and the peak of the concentration moves closer to the surface. The nitrogen is gathered near the surface, and does not become in-diffusion to the bulk of the wafer. The silicon nitride layer near the surface prevents to inject the additional nitrogen into the bulk of the wafer across the layer. The nitrogen does not affect the formation of BMD. On the other hand, the oxygen is moved into the bulk of the wafer by increasing pressure. Dz depth from the surface is extended into the bulk because the nuclei of BMD move into the bulk of the wafer.

• Korean Journal of Materials Research
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• v.8 no.10
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• pp.931-937
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• 1998

The electrical conductivity of undoped mtile was measured in the oxygen partial pressure range of $1~10{-23}$atm and temperature range of $700~1300^{\circ}C$ to investigate the defect types and the electrical properties. The data(logu/logPoz) were divided into the five regions. Therefore the five dominant defect types such as $Ti_nO_{2n-1}$, Ti, Vo, Vo due to impurity, and n-p transition or p-type conduction with the Poz and the temperature were proposed. The formation enthalpies calculated from these experimental results were found to be 10.2eV for Ti, and 4. 92eV for Vo in intrinsic range.

• Anatomy and Cell Biology
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• v.57 no.3
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• pp.468-472
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• 2024

In this report, atlantooccipital assimilation (AS), anterior arch defect (AAD), and posterior arch defect (PAD) of the atlas, and several variations around the craniocervical junction were identified on computed tomography (CT) of a patient of unknown sex and age. Coronal and sagittal CT scans showed AS and bilateral fusion of the atlas and the base of occipital bone. Axial CT scan at the atlas revealed PAD type B on the left side and midline AAD. Morphometric measurements indicated a potential ventral spinal cord compression. In addition, mid-sagittal CT revealed the presence of fossa navicularis magna and incomplete formation of the transverse foramen on the right side. This study reports an extremely rare AS associated with AAD, PAD, and other variations of the clivus and the atlas. To our knowledge, no similar case has been reported in the literature.

• Archives of Reconstructive Microsurgery
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• v.21 no.2
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• pp.137-142
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• 2012

Purpose: To report the clinical and radiological result of the vascularized fibular epiphyseal transplantation in the treatment of humeral head deformity by septic arthritis Material & Methods: A 3 years old male who has humeral head deformity and bone defect by septic arthritis on neonatal period. We replaced bone defect as vascularized fibular epiphyseal transplantation and lengthened humerus shaft for humerus discrepancy. We followed it up for 14 years. Result: We saw the callus formation 2 months after surgery and obtained bone union, one year after surgery. The transplanted fibular bone got hypertrophy. We could check full range of motion on lt. shoulder and The bone deformity was not worsened and The graft did not displaced on last follow up. Conclusion: Humeral head reconstruction by vascularized fibular epiphyseal transplantation showed good clinical outcome.

• Journal of Korea Foundry Society
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• v.37 no.6
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• pp.181-185
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• 2017

In the present study, the effect of cooling rate on the formation of the porosity in the thick aluminum sand casting was investigated. Nowadays, due to considerations of weight and cost reduction, large scale thick aluminum casting has replaces steel frames for vacuum chambers for semiconductor production. Several thick aluminum castings were manufactured using chill with temperature measurements. The castings were inspected using 3D computed tomography in order to quantify the porosity defect density in the castings. Effects of the thickness of the chill on the porosity defect density were discussed.

• Journal of Veterinary Clinics
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• v.18 no.2
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• pp.156-159
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• 2001

A 6-year-old male mongrel dog with a 7-month history of ulnar-radial nonunion fracture was treated with implantation of recombinant human bone morphogenetic protein-2 (rhBMP-2). The dog had received surgical correction three times prior to the admission but radiography of the affected limb revealed a typical figure of nonunion fracture. Glossly, the fractured ends were sclerotic and the area between the ends was filled with fibrous tissue. After debridement the shaft was fixed by an 10-hole plate. rhBMP-2 at a total dose of 256 micrograms was implanted with a synthetic carrier into the 10-mm defect formed by the debridement. Callus formation responding to rhBMP-2 was radiographically observed at 4 weeks after implantation and the defect bridged both fracture ends by 8 weeks after implantation. The plate was removed at 12 months after implantation. Any complications were not observed for 5 months after removal of the plate.