• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권2호
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• pp.78-81
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• 2000

The closed-form analytic solutions for the breakdown voltage of 6H-SiC RTD(silicon carbide reachthrough diode) having metal$-n^--n^+$ Schottky structure or $p^+-n^--n^+$, are successfully derived by solving impact ionization integral using an effective ionization coefficient. For the lightly doped n- epitaxial layer, the breakdown voltage of SiC RTD are nearly constant with the increased doping concentration while the breakdown voltages decrease for the heavily doped epitaxial layer.

• 한국결정학회지
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• 제4권2호
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• pp.92-99
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• 1993

Diethylzinc를 사용하여 PECVD장치로 ZnO 박막을 증 착하여 미세구조를 분석하였다. 기판 온도 100℃에서부터 이미 미세 결정 입자로 구성된 ZnO 박막의 증착이 가능했으며, 200℃이상에서는 C 축 배향성이 뛰어난 ZnO 박막이 유리 기판위에 증착되었다. c-면 사파이어 기판위에 증착된 ZnO 박막을 TEM으로 분석한 결과 기판 온도 350℃에서 EPITAXIAL (002) ZnO 박막이 성장됐으며, 입계에서는 Moire패턴에 의한 dislocation이 관찰되었다.

• 한국결정학회:학술대회논문집
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• 한국결정학회 2002년도 정기총회 및 추계학술연구발표회
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• pp.17-17
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• 2002

Time-of-flight impact collision ion scattering spectroscopy (TOF-ICISS) was applied to study the geometrical structure of the epitaxially grown BaTiO₃ layers on the MgO(100) surface. Hetero-epitaxial BaTiO₃ layers can be deposited by the following steps: first thermal evaporation of titanium onto the MgO(100) surface in the atmosphere of oxygen at 400℃, secondly thermal evaporation of barium in the same manner, and finally annealing at 800℃. Well ordered perovskite BaTiO₃ was confirmed from the ICISS spectra and reflection high electron energy diffraction (RHEED) patterns. It was also revealed that BaTiO₃ had cubic structure with the same lattice parameter of bulk phase.

• 한국결정성장학회지
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• 제10권1호
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• pp.13-16
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• 2000

Progress in Si crystal and wafer technologies is discussed on single crystal growth, wafer fabrication, epitaxial growth, gettering, 300 mm and SOI. As for bulk crystal growth, the mechanism of grown-in defects (voids) formation, the succes of grown-in defect free crystal growth technology and nitrogen doped crystal are shown. New wafer fabrication technologies such as both-side mirror polishing and etchingless process have been developed. The epitaxial growth of SiGe/Si heterostructure for high speed bipolar device is treated. Gettering technology under low temperature process such as RTP is important, and also it is shown that IG effect for Ni could be predicted using computer simulation of precipitate density and size. The development of 300 mm wafer and SOI has made progress steadily.

• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 1998년도 PROCEEDINGS OF THE 15TH KACG TECHNICAL MEETING-PACIFIC RIM 3 SATELLITE SYMPOSIUM SESSION 4, HOTEL HYUNDAI, KYONGJU, SEPTEMBER 20-23, 1998
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• pp.3-7
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• 1998

The rare-earth ions (R3+, R=Nd, Er) doped CaF2 layers have been grown on CaF2(111) substrate by molecular beam epitaxy. The epitaxial relationship and the crystallinity of CaF2:R3+ layers depending on the concentration of R3+ were studied by reflection high-energy electron diffraction (RHEED). In aspect of application as buffer layer in semiconductor-related hybrid structure, the lattice displacement between CaF2:R3+ layers and CaF2(111) substrate was investigated by X-ray rocking curve analysis.

• 한국결정성장학회지
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• 제10권5호
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• pp.350-355
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• 2000

수평 Bridgeman방식으로 성장된 C축 방향의 사파이어 결정기판을 연마 가공하였으며, 또한 유기금속 기상화학 증착 방법으로 사파이어 기판 위에 GaN 박막을 증착하였다. 사파이어 인고트를 성장하여 2인치 사파이어 기판으로 이용하였으며 웨이퍼 절편장치 및 연마장치를 개발하였다. 이러한 다단계의 연마 가공은 기판 표면을 경면화하였다. 표면 평탄도 및 조도는 원자힘현미경으로 측정하였다. 개발된 사파이어 기판위에 성장된 GaN 박막의 특성 및 청색광소자로의 응용 가능성을 확인하였다.

• Journal of Magnetics
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• 제7권2호
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• pp.51-54
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• 2002

The crystallization of amorphous Ba-ferrite/sapphire(001) thin films was studied in real-time synchrotron x-ray scattering experiments. In the sputter-grown amorphous films, we found the existence of epitaxial $Fe_3O_4$ interfacial crystallites (50-${\AA}$-thick), well aligned $[0.03^circ$full-width at half-maximum (FWHM)] to the sapphire [001] direction. The amorphous precursor was crystallized to epitaxial Ba-ferrite and \alpha-Fe_2O_3$grains in two steps; i) the nucleation of crystalline \alpha-Fe_2O_3$ phase started at $300^circ{C}$ together with the transformation of the $Fe_3O_4$ crystallites to the \alpha-Fe_2O_3$ crystallites, ii) the nucleation of Ba-ferrite phase occurred at temperature above $600^circ{C}$. In the crystallized films irrespective of the film thickness, the crystal domain size of the \alpha-Fe_2O_3$grains was about 250 ${\AA}$ in the film plane, similar to that of the Ba-ferrite grains.

• 한국재료학회지
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• 제14권5호
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• pp.363-367
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• 2004

Recently ZnO epitaxial layers have been widely studied as a semiconductor material for optoelectronic devices. Sapphire and silicon are commonly selected as substrate materials for ZnO epitaxial growth. In this communication, we report the effect of the ECR plasma pretreatment of sapphire and silicon substrates on the nucleation in the ZnO ALE (atomic layer epitaxy). It was found that ECR plasma pretreatment reduces the incubation period of the ZnO nucleation. Oxygen ECR plasma enhances ZnO nucleation most effectively since it increases the hydroxyl group density at the substrate surface. The nucleation enhancing effect of the oxygen ECR plasma treatment is stronger on the sapphire substrate than on the silicon substrate since the saturation density of the hydroxyl group is lower at the sapphire surface than that at the silicon surface.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.212-217
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• 2000

Bi$_2$Sr$_2$CuO$_{x}$(Bi-2201) thin films have been fabricated by atomic layer-by-layer deposition using ion beam sputtering(IBS) process. During the deposition, 14 wt%-ozone/oxygen mixture gas of typical pressure of 5.0$\times$10$^{-5}$ Torr is supplied with ultraviolet light irradiation for oxidation. XRD and RHEED investigations reveal that a buffer layer with compositions different from Bi-2201 is formed at the early deposition stage of less than 10 units cell and then Bi-2201 oriented along the c-axis is grown.n.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
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• pp.281-283
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• 2001

Bi$_2$Sr$_2$CuO$\_$x/(Bi-2201) thin films were fabricated layer-by-layer deposition using an ion beam sputtering method. 10 wt% and 90 wt% ozone mixed with oxygen were used ultraviolet light irradiation to assist oxidation. At early stages of the atomic layer by layer deposition, two dimensional epitaxial growth which covers the substrate surface would be suppressed by the stress and strain caused by the lattice misfit, then three dimensional growth takes place. Since Cu element is the most difficult to oxidize, only Sr and Bi react with each other predominantly, and forms a buffer layer on the substrate in an amorphous-like structure, which is changed to SrBi$_2$O$_4$ by in-situ anneal.