As 이온 주입된 비정질 탄소 박막의 마이크로플라즈마 화학기상증착법에 의한 자동 어닐링 효과에 관한 연구

조의식,권상직,Cho, E.S.,Kwon, S.J. 한국진공학회 2013 Applied Science and Convergence Technology Vol.22 No.1

마이크로플라즈마 화학기상증착법(microwave plasma enhanced chemical vapor deposition, MPCVD)에 의하여 형성된 비정질 탄소 박막의 효율적인 도핑 공정을 위하여, 비정질 탄소 박막의 성장 직전 nucleated seed 상태의 기판 혹은 일부 성장된 박막 위에 비소(As) 이온을 이온 주입하였고 그 직후 다시 MPCVD에 의하여 박막을 성장시켰다. MPCVD에 의한 성장 자체가 약 $500{\sim}600^{\circ}C$ 온도에서의 어닐링 공정을 대체할 수 있으므로, 기존의 이온 주입 후 별도의 어닐링 공정과 비교 시 간략화된 공정으로도 어닐링 효과가 있다고 할 수 있다. 이온 주입 후 박막 성장으로 어닐링 효과를 얻은 비정질 탄소 박막의 경우, $2.5V/{\mu}m$의 전계에서 약 $0.1mA/cm^2$의 전계 방출 특성을 관찰할 수 있었고 또한 라만 스펙트럼 특성에서도 다이아몬드 특성 및 그래파이트 특성 모두 뚜렷이 관찰되었다. 전기적, 구조적 특성 관찰로부터 이온 주입된 As 이온이 자동 어닐링 효과에 의해 충분히 비정질 탄소 박막에 도핑되었다고 할 수 있다. For the simplification of doping process in amorphous carbon film, arsenic (As) ions were implanted on the nucleated silicon wafer before the growth process. Then amorphous carbon films were grown at the condition of $CH_4/H_2=5%$ by microwave plasma chemical vapour deposition. Because the implanted seeds were grown at the high temperature and the implanted ions were spread, it was possible to reduce the process steps by leaving out the annealing process. When the implanted amorphous carbon films were electrically characterized in diode configuration, field emission current of $0.1mA/cm^2$ was obtained at the applied electric field of about $2.5V/{\mu}m$. The results show that the implanted As ions were sufficiently doped by the self-annealing process by using the growth after implantation.

전면 유기발광 다이오드 제작시 Mg:Ag 캐소드 최적화 및 LiF 전자주입층 유무에 따른 소자 특성에 관한 연구

조의식,송민석,권상직 한국반도체디스플레이기술학회 2022 반도체디스플레이기술학회지 Vol.21 No.1

For the process simplification in the fabrication of organic light emitting diode(OLED), top emission OLED(TEOLED) was fabricated without lithium fluoride(LiF) used as an electron injection layer (EIL). After co-deposition of Mg and Ag with a different process conditions, a cathode material adjacent to EIL was optimized when Mg and Ag have a ratio of 1:9 considering sheet resistance and transmittance. From the energy band diagram of TEOLED, band gap difference between Trisaluminium (Alq3) and Mg:Ag cathode show the difference of 0.4 eV according to the usage of LiF The fabricated TEOLED without LiF showed the improvement of 5.2 % and 2.7 % in the luminance and the current density comparing that with LiF. The results show there is no significant difference in OLED characteristics regardless of LIF layer in the TEOLED structures.

산소 이온 빔에 의한 산화 알루미늄 박막의 식각 효과 및 정전 용량 특성에 관한 연구

조의식,권상직,Cho, E.S.,Kwon, S.J. 한국진공학회 2013 Applied Science and Convergence Technology Vol.22 No.1

고유전율 절연체의 한 종류인 산화알루미늄 박막을 전자빔 증착법으로 형성하는 과정에서 산소 이온 빔의 조사를 이용, 산소 이온 빔 보조 증착 효과를 기대하였다. 산소 이온 보조 증착법으로 형성된 산화 알루미늄 박막의 두께 측정 결과, 높은 에너지에서의 이온 빔에 의한 식각 효과를 확인할 수 있었으며, 산소 이온 보조 증착 결과보다 높은 커패시턴스 값도 관찰할 수 있었다. For the realization of high-k insulator, aluminum oxide ($Al_2O_3$) was deposited by using an oxygen ion beam assisted deposition (IBAD) during e-beam evaporation. From the thickness of the $Al_2O_3$ layer evaporated with IBAD process, it was possible to investigate the etching effect of ion beam at higher energies during e-beam evaporation. It was also possible to obtain a higher capacitance as a result of IBAD in spite of the reduced thickness of $Al_2O_3$.

Effects of Photon Energy Spectrum on the Photocurrent of Hydrogenated Amorphous Silicon Thin Film Transistor by Using Frequency Filters

조의식,권상직 한국전기전자재료학회 2013 Transactions on Electrical and Electronic Material Vol.14 No.1

Frequency filters with various filtering wavelengths were used in the photoelectric characterization of hydrogenated amorphous silicon thin film transistor (a-Si:H TFT) and the experimental results were described and analyzed in terms of the photon energy spectral characteristics calculated from the integration of the photon energy and the spectral intensity of transmitted backlight through the filters at each wavelength. From the comparison of the photocurrents and the calculated photon energy spectrums for the filtered ranges of wavelength, it was possible to conclude that the photocurrents are closely related to the photon energy spectrums of the backlight.

Fabrication of Sputtered Gated Silicon Field Emitter Arrays with Low Gate Leakage Currents by Using Si Dry Etch

조의식,권상직 한국전기전자재료학회 2013 Transactions on Electrical and Electronic Material Vol.14 No.1

A volcano shaped gated Si-FEA (silicon field emitter array) was simply fabricated using sputtering as a gate electrode deposition and lift-off for the removal of the oxide mask, respectively. Due to the limited step coverage of wellcontrolled sputtering and the high aspect ratio in Si dry etch caused by high RF power, it was possible to obtain Si FEAs with a stable volcano shaped gate structure and to realize the restriction of gate leakage current in field emission characteristics. For 100 tip arrays and 625 tip arrays, gate leakage currents were restricted to less than 1% of the anode current in spite of the volcano-shaped gate structure. It was also possible to keep the emitters stable without any failure between the Si cathode and gate electrode in field emission for a long time.

1. 한국 성인 상악 중절치 치근의 근관 면적비 및 폭경비에 의한 연령추정

조의식,장기완,박병건,이무삼 대한체질인류학회 1991 대한체질인류학회 학술대회 연제 초록 Vol.34 No.-

Constitutive Activation of Smoothened Leads to Impaired Developments of Postnatal Bone in Mice

조의식,이정채,Shin-Saeng Lim,임신생 한국분자세포생물학회 2012 Molecules and cells Vol.34 No.4

Sonic hedgehog (Shh) signaling regulates patterning, proliferation, and stem cell self-renewal in many organs. Smoothened (Smo) plays a key role in transducing Shh signaling into the nucleus by activating a glioma family of transcription factors; however, the cellular and molecular mechanisms underlying the role of sustained Smo activation in postnatal development are still unclear. In this study, we explored the effects of Shh signaling on bone development using a conditional knock-in mouse model that expresses a constitutively activated form of Smo (SmoM2) upon osteocalcin (OCN)-Cre-mediated recombi-nation (SmoM2; OCN-Cre mice). We also evaluated the expression pattern of bone formation-related factors in primary calvarial cultures of mutant and control mice. The SmoM2;OCN-Cre mutant showed growth retardation and reduction of bone mineral density compared to control mice. Constitutively activated SmoM2 also repressed mRNA expression of Runx2, osterix, type I collagen, and osteocalcin. Further, sustained SmoM2 induction suppressed mineralization in calvarial primary osteoblasts cultures, whereas such induction did not affect cell proliferation in the mutant cultures as compared with SmoM2 only control cultures. These results suggest that sustained Smo activation inhibits postnatal development of bone by suppressing gene expression of bone formation regulatory factors in mice.

The Effects of Rosiglitazone on Osteoblastic Differentiation, Osteoclast Formation and Bone Resorption

조의식,이정채,Myoung-Kyun Kim,손영옥,Keun-Soo Lee,박승문 한국분자세포생물학회 2012 Molecules and cells Vol.33 No.2

Rosiglitazone has the potential to activate peroxisome proliferator-activated receptor- (PPAR), which in turn can affect bone formation and resorption. However, the mecha-nisms by which rosiglitazone regulates osteoclastic or osteoblastic differentiation are not fully understood. This study examines how rosiglitazone affects osteoclast for-mation, bone resorption and osteoblast differentiation from mouse bone marrow. Rosiglitazone treatment not only inhibited the formation of tartrate-resistant acid phosphatase-positive cells, but also prevented pit forma-tion by bone marrow cells in a dose- and time-dependent manner. Rosiglitazone also suppressed the receptor acti-vator of nuclear factor (NF)-B ligand (RANKL) receptor (RANK) expression but increased PPAR2 expression in the cells. In addition, rosiglitazone diminished RANKL-induced activation of NF-B-DNA binding by blocking IB phosphorylation. Furthermore, it reduced collagen and osteocalcin levels to nearly zero and prevented mRNA expression of osteoblast-specific proteins including runt-related tran-scription factor-2, osteocalcin, and type I colla-gen. How-ever, mRNA levels of adipocyte-specific marker, aP2, were markedly increased in the cells co-incubated with rosigli-tazone. These results suggest that PPAR acti-vation by rosiglitazone inhibits osteoblast differentiation with in-creased adipogenesis in bone marrow cells and also may prevent osteoclast formation and bone resorp-tion in the cells.

OLED의 Thin Film Encapsulation을 위한 MgO 박막의 원자층 증착 장치 및 공정에 관한 연구

조의식,권상직,Cho, Eou Sik,Kwon, Sang Jik 한국반도체디스플레이기술학회 2021 반도체디스플레이기술학회지 Vol.20 No.3

Thin-film encapsulation (TFE) technology is most effective in preventing water vapor and oxygen permeation in the organic light emitting diodes (OLED). Of those, a laminated structure of Al₂O₃ and MgO were applied to provide efficient barrier performance for increasing the stability of devices in air. Atomic layer deposition (ALD) method is known as the most promising technology for making the laminated Al₂O₃/MgO and is used to realize a thin film encapsulation technology in organic light-emitting diodes. Atomic layer deposited inorganic films have superior barrier performance and have advantages of excellent uniformity over large scales at relatively low deposition temperatures. In this study, the control system of the MgCP₂ precursor for the atomic layer deposition of MgO was established in order to deposit the MgO layer stably by the injection time of second level and the stable heating temperature. The deposition rate was obtained stably to be from 4 to 10 Å/cycle using the injection pulse times ranging from 3 to 12 sec and a substrate temperature ranging from 80 to 150 ℃.

한국 성인 상악 중절치 치근의 근관 면적비 및 폭경비에 의한 연령추정

조의식(CHO Eui-Sic),장기완(CHANG Kee-Wan),박병건(PARK Byoung-Keon),이무삼(LEE Moo-Sam) 대한체질인류학회 1991 대한체질인류학회지 Vol.4 No.1

저자들은 1989년 7월 1일부터 1990년 8월 30일 사이에 전북대학교 치과병원에 내원한 성인 남. 녀 환자의 건강한 상악 중절치 605개를 대상으로 촬영한 표준 구강방사선 사진을 각 연령군 (20대, 30대, 40대, 50대, 60대별로 구분하고 화상분석기상에서 근관면적비 및 근관폭경비를 동기 계측하여 연령 증가에 따르는 경향을 조사한 바 다음돠 같은 결론을 얻었다.) 1.남, 녀 성별 근관폭경비의 차이는 없으나(p0.05). 근관면적비에 있어서는 남. 녀 성별 차이가 있었다(p0.01) 2.근관면적비를 개인의 연령추정에 이용할 때에 연령과 근관면적비의 상관관계는 남, 녀에서 모두 r=0.82이었고, 희귀방정식은 남,녀에서 각각v=6.01v+4.35와 v=7.02v-3.38(단; v:연령 v:근관면적비 p0.01)로 나타났다. 이상의 시험결과를 국내에서 조사발표된 보고들의 성적과 비교하여 볼 때 연령의 증가에 따르는 근과면적비 및 근괌폭경비의 경향은 유사하였으며, 40대 이후의 연령군에서 근관면적비와 근관폭경비의 변화 폭은 크게 나타나서 치아를 총한 연령감성에 화상분석기를 이용하는 것이 오파를 줄이는데 유용하리라 .사료된다.