A Study on the Fabrication of the Convex Structured MOSFET and Its Electrical Characteristics

김기홍,김현철,김흥식,안철,Kim, Gi-Hong,Kim, Hyun-Chul,Kim, Heung-Sik,An, Chul The Institute of Electronics and Information Engin 1992 전자공학회논문지-A Vol.29 No.8

To improve the characteristics of sub$\mu$m short channel MOSFET device, a new device having the convex structure is proposed. This device has 3-dimensionally expandable channel length according to the vertical etched silicon height. For the purpose of comparing the DC and AC characteristics, planar device is also fabricated. Comparing the channel length, the convex device with 0.4$\mu$m silicon height is larger about 0.56$\mu$m in NMOS and 0.78$\mu$m in PMOS than planar devices. DC characteristics, such as threshold voltage, operational current, substrate current and breakdown voltage are compared together with AC characteristics using the ring oscillator inverter delay. Also process and device simulation are performed and the differences between convex and pranaldevice are also compared.

모바일 혼합현실 기술

김기홍,김홍기,정혁,김종성,손욱호,Kim, Gi-Hong,Kim, Hong-Gi,Jeong, Hyeok,Kim, Jong-Seong,Son, Uk-Ho 한국전자통신연구원 2007 전자통신동향분석 Vol.22 No.4

혼합현실 기술을 휴대가 용이한 모바일 기기상에서 효과적으로 구현하기 위해서는 기기에 부착된 카메라의 위치를 인식하는 기술을 시작으로 입력된 실세계 공간에 가상의 디지털 정보를 정합하고 표현하는 기술, 사용자가 표현된 혼합현실 환경과 현실감있게 상호작용하는 기술, 그리고 다양한 응용분야에 맞게 혼합현실 콘텐츠를 저작하는 기술에 이르기까지 여러 가지 세부 기술들이 요구된다. 본 논문에서는 언급한 세부 기술들에 대한 개요와 국내외적으로 진행되고 있는 관련 기술들의 동향을 구체적인 사례를 통해 소개한다.

방사성고화체로부터의 $^{60}$ Co, $^{137}$ Cs 침출에 대한 표준시험법의 상호비교

김기홍,유영걸,정경기,홍권표,이락희,정의영,고덕준,김헌,Kim, Ki-Hong,Ryu, Young-Gerl,Chung, Kyung-Ki,Hong, Kwon-Pyo,Lee, Nak-Hee,Jeong, Yi-Yeong,Koh, Duck-Joon,Kim, Heon 한국방사성폐기물학회 2003 방사성폐기물학회지 Vol.1 No.1

IAEA, FT-04-020 및 ANS 16.1의 침출시험법을 각각 수행하여 얻은 시험결과를 이용하여 상호 비교 평가하였다. 붕산을 함유한 파라핀 및 시멘트 고화체에서의 $^{60}$Co 과 $^{137}$Cs의 ANS 16.1의 침출지수는 6이상이었으나 고화매질과 탈염수의 종류에 따라 상반되는 침출거동을 보였다. 침출수로 합성해수와 탈염수를 사용하였을 경우 $^{60}$Co는 시멘트 고화체에서는 합성해수, 파라핀 고화체에서는 탈염수에서 침출이 높았다. 반면에 $^{137}$Cs의 침출정도는 시멘트에서는 탈염수, 파라핀에서는 합성해수에서 높았다. $^{60}$Co의 침출분율은 시멘트 고화체에서 IAEA > ANS > FT의 순으로 높았으며, 반대로 파라핀고화체에서는 이의 역순이었다. IAEA, FT-04-020, and ANS 16.1, standard leaching test methods, were evaluated comparatively with their test results. Leaching index of $^{60}$ Co and $^{137}$ Cs by ANS 16.1 method for waste forms of paraffin and cement were above 6.0. Their leaching behavior were depending on the type of matrix and leachant. Leachability of $^{60}$ Co for cement waste form was higher in simulated seawater than do-mineralized water, and was higher in de-mineralized water for paraffin waste form. leachability of $^{60}$ Co was contrary to $^{137}$ Cs. Cumulative fraction leached of $^{60}$ Co was higher in order or IAEA > ANS > FT in a cement waste form.

오자연종환(五子衍宗丸)이 노화유발(老化誘發) 흰주의 항산화능(抗酸化能)에 미치는 영향(影響)

김기홍,정국훈,김광호,고성규,Kim, Ki-Hong,Ding, Guo-Xun,Kim, Kwang-Ho,Ko, Seong-Gyu 대한예방한의학회 2005 대한예방한의학회지 Vol.9 No.1

Objectives : Ojayeonjonghwan(五子衍宗丸) is composed of Polygonum multiflorum THUNB, and some medical herbs that are known as formula of senescence delay effects. The purpose of this study is to investigate th effect of Ojayeonjonghwan on antioxidant enzyme activities, such as Thiobarbituric acid reactive substance(TBARS), Superoxide dismutase(SOD), Catalase(CAT), Glutathione preoxidase (GSH-px) in rat erythrocytes and blood plasma. Methods : Sprague-Dawley rats were divided into 3 groups, Normal group (supplied enough water and feeds only, Normal Group), D-galatose administered group(injected D-galatose 50mg/kg, 1time/day for 6 weeks, Control Group) and Ojayeonjonghwan administered group (D-galactose 50mg/kg and Ojayeonjonghwan extracts 245.0mg/200g 1time/day for 6 weeks, OJY Group). Rats were sacrificed and TBARS, SOD, CAT, GSH-px, Plasma total lipid, Plasma triglyceride and cholesterol were measured in rat erythrocytes and blood plasma. Results : TBARS in plasma concentration of OJY group was significantly lower than that of control group. Red blood cell(RBC) SOD activity of OJY group was significantly higher than that of control group(F=16.057, p=0.0001, ANOVA test), RBC GSH-px activity of OJY group was increased(F=4.271, p=0.034, ANOVA test). RBC catalase activities of all experimental group were not significantly different. Total lipid and triglyceride concentration in plasma of all experimental groups were not significantly different. Total cholesterol concentrations in plasma of OJY group were significantly lower than those of control group(F=4.387, p=0.032, ANOVA test). Conclusions : According to the above results, it is considered that Ojayeonjonghwan is effective in inhibiting lipid peroxidation and increasing antioxidative enzyme activities in D-galactose induced aging rat.

n-GaAs 구조에서의 ArF excimer laser annealing에 따른 Photoreflectance 특성 연구

김기홍,유재인,심준형,배인호,임진환,김진희,유재용,Kim, Ki-Hong,Yu, Jae-In,Sim, Jun-Hyoung,Bae, In-Ho,Lim, Jin-Hwan,Kim, Jin-Hi,Yu, Jae-Yong 한국진공학회 2007 Applied Science and Convergence Technology Vol.16 No.2

n-GaAs의 시료를 furnace annealing 처리와 laser annealing 처리를 한 후, PR 방법으로 비교 조사하였다. 시료는 Furnace annealing을 5 분간 $400{\sim}800^{\circ}C$에서 처리한 시료와 ArF excimer laser($30{\sim}50\;W$)로 5 분간 Laser annealing 처리 한 시료로 준비하였다. Furnace로 annealing을 한 경우에 주 신호(정점)는 1.43 eV에서 관측되었는데 비해 laser로 annealing 한 샘플은 1.42 eV로 0.01 eV가 더 작게 관측되었다. 이는 laser annealing이 furnace annealing 보다 표면과 내면에서 일어나는 열처리 효과가 더 고르게 일어나가 때문이다. We investigated variation of the photoreflectance(PR) signals for n-GaAs furnace and laser annealed. The samples were annealed by using ArF excimer laser(5 min, $30{\sim}50\;W$) and furnace(5 min $400{\sim}700^{\circ}C$). The PR signals(top point) measured from the ArF excimer laser annealed sample showed 1.42 eV and furnace annealed sample showed 1.43 eV. This result is ArF excimer laser annealed sample was uniform annealed surface and inter state.

히르쉬스프룽병의 병변부위에서 nNOS 발현

김기홍,김한성,이성철,Kim, Ki-Hong,Kim, Han-Seung,Lee, Seong-Cheol 대한소아외과학회 2005 소아외과 Vol.11 No.1

Abnormal distribution of enteric nerves such as adrenergic, cholinergic and non-adrenergic non-cholinergic nerves (NANC) may cause the failure of relaxation at the involved bowel segment in Hirschsprung's disease (HD). Nitric oxide (NO) is a major inhibitory NANC neurotransmitter in the gastrointestinal tract. NO is synthesized by activation of nNOS (neuronal nitric oxide synthase) in the intramural ganglion cells and regulates bowel movement. To assess the distribution of nNOS in HD, immunohistochemical staining to nNOS was utilized on paraffin embedded specimens. Ten control colon specimens were tested for feasibility of staining. Immunohistochemisrty was done on ganglionic colon as well as aganglionic segment of 15 patients with HD. nNOS immunoreactivity was observed in the neuronal cells, small cells and nerve fibers in the muscle layer and submucosal neuronal cells of control specimens. This finding was also observed in the ganglionic segments of HD. But, there was no nNOS immunoreactivity in aganglionic segments of HD. In conclusion nNOS immunohistochemical staining of paraffin embedded specimen is feasible and reliable. And the results suggest that the relaxation failure of the aganglionic bowel in HD is related to the absence of nNOS containing cells and nerve fibers.

남강댐하류의 물리적 하천교란 평가

김기홍,Kim, Ki-Heung 한국환경복원기술학회 2008 한국환경복원기술학회지 Vol.11 No.3

To assessment the disturbances of the Namgang caused by dam construction, upstream area was selected for the reference reach and downstream area was selected for the comparison reach. And these reaches were surveyed and analyzed according to the assessment criteria of the river disturbances.The artificial factors of river disturbances were classified as river improvement works, dam construction and aggregate dredging. The indexes were physical factors as like epifaunal (bottom), embeddedness, velocity/depth regime, sediment deposition, channel flow status, channel alteration, frequency of riffles, bank stability, vegetative protection, riparian zone etc.The assessment results showed 46% of the assessment criteria which was serious status in dam downstream area and 89.5% of it which was excellent status in dam upstream.Finally, the results showed that physical river environment in downstream area was disturbed by the discharge control and the interception of sediment discharge by dam, consequently this disturbance give rise to impact of ecosystem in river.

In_xGa_1-xN/GaN 다중양자우물 구조의 광학적 성질 연구

김기홍,김인수,박헌보,배인호,유재인,장윤석,Kim, Ki-Hong,Kim, In-Su,Park, Hun-Bo,Bae, In-Ho,Yu, jae-In,Jang, Yoon-Seok 한국진공학회 2009 Applied Science and Convergence Technology Vol.18 No.1

$In_xGa_{1-x}N$/GaN 다중양자우물 구조의 EL 특성을 온도와 주입전류 변화에 따른 특성을 조사하였다 저전류와 고전류 주입시 EL 효율의 온도 의존 변화는 매우 다르게 나타나는데, 이러한 온도와 전류의 변화에 의한 독특한 EL 효율의 변화는 내부전기장의 존재 하에 순방향 바이어스에 기인한 외부전기장의 영향인 것으로 볼 수 있다. 그리고 $In_xGa_{1-x}N$/GaN 다중양자우물 구조에서 In 성비의 증가는 발광파장위치의 적색이동을 보였다. 15K에서 주입 전류의 증가에 따라 녹색 양자우물 구조는 80 meV와 청색 양자우물 구조는 22 meV의 청색 편이를 하였다. 이는 전류의 증가에 의해 단위 시간당 생성되는 캐리어 수가증가하게 되고 그에 따라 subband가 급격히 채워지는 band filling 현상이 일어나게 되어 짧은 파장에서 재결합이 증가하기 때문이다. 그리고 청색과 녹색 다중 양자우물구조의 짧은 파장 쪽으로의 편이 차이는 In 농도에 기인한 것으로 In 농도가 높으면 양자우물 깊이가 증가되어 더 강한 양자속박효과가 작용하여 캐리어 구속력이 증가하기 때문 것으로 볼 수 있다. Temperature and injection current dependence of electroluminescence(EL) spectral intensity of the $In_xGa_{1-x}N$/GaN multi-quantum wells(MQW) have been studied over a wide temperature range and as a function of injection current level. It is found that a temperature-dependent variation pattern of the EL efficiency under very low and high injection currents shows a drastic difference. This unique EL efficiency variation pattern with temperature and current can be explained field effects due to the driving forward bias in presence of internal(piezo and spontaneous polarization) fields. Increase of the indium content in $In_xGa_{1-x}N$/GaN multiple quantum wells gives rise to a redshift of 80 meV and 22 meV for green and blue MQW, respectively. It can be explained by carrier localization by potential fluctuation of multiple quantum well and MQW structures also shows a keen difference owing to the different indium content in InGaN/GaN MQW.

표면 광전압 방법에 의한 ${Al_{0.24}}{Ga_{0.76}}As/GaAs$ 다중 양자우물 구조의 광 흡수 특성

김기홍,최상수,손영호,배인호,황도원,신영남,Kim, Gi-Hong,Choe, Sang-Su,Son, Yeong-Ho,Bae, In-Ho,Hwang, Do-Won,Sin, Yeong-Nam 한국재료학회 2000 한국재료학회지 Vol.10 No.10

$Al_{0.24}Ga_{0.76}As/GaAs$ 다중 양자우물 구조의 고아 흡수 특성을 표면 광전압 방법을 사용하여 연구하였다. SPV 측정결과 1.42eV 부근에서 두 개의 신호가 나탔으며, 이는 화학적 에칭으로 GaAs 기판의 신호와 GaAs 완충층과 관련된 신호임을 확인 할 수 있었다. $Al_{0.24}Ga_{0.76}As$와 관련된 전이 에너지를 관찰하고, Kuech 등이 제안한 조성식을 이용하여 Al 조성(x=24%)을 결정하였다. 그리고 다중 양자우물에서 나타나는 전이 에너지 값들은 envelope-weve function approximation(EFA)로 계산한 이론치와 잘 일치하였다. 입사광의 세기에 따라 광 전압이 선형적으로 변한다는 것을 알 수 있었고, 온도가 감소함에 따른 전이 에너지의 변화를 관찰하였다. The characteristics of optical absorption in $Al_{0.24}Ga_{0.76}As/GaAs$ multi-quantum wells(MQWs) structure were investigated by using the surface photovoltage(SPV). The Spy features near 1.42 eV showed two overlapping signals. By chemical etching, we found associated with the GaAs substrate and the GaAs cap layer. The Al composition(x=24 %) was determined by Kuech's composition formula. In order to identify the transition energies. the experimentally observed energies were compared with results of the envelope function approximation for a rectangular quantum wells An amplitude variation of the relative Spy intensity from the GaAs substrate, llH, and llL was observed at different light intensities. A variation in the SPY line shape of the transition energies were observed with decreasing tempera­t ture.

대구지역 대학생 가족에서 족부 백선의 유병율

김기홍,조해욱,신동훈,최종수,방용준,서순봉 ( Ki Hong Kim,Hae Ook Cho,Dong Hoon Shin,Jong Soo Choi,Young Jun Bang,Soon Bong Suh ) 대한피부과학회 1997 대한피부과학회지 Vol.35 No.1

Background: Tinea pedis is one of the most comrnon dermatoses in the general population. But its prevalence in the general populat,ion was not yet reported in Korea. Objective : Prevalence of tinea pedis and associated tinea unguium were checked in the general population. Methods : Six hundred fifty eight persons from 179 families of the college students were evaluated. Clinical examinatior. for tinea pedis and onychomycosis and collecting scales from the suspicious lesions of the family members were perforrned by educated college students. Then dermatologists exarnined those specimens mycologically by KOH ~tnount and fungal culture. Results . The results were as follows 1. The prevalence of tinea pedis was 41.2% in the studied 658 persons. 2. Among all 271 patients with tinea pedis, 201 strains of dermatophytes were isolated. They were 143 strains of Trichophyton(T) rubrum, 49 strains of T. mentagrophytes and 9 mixed infections of T. rubrum and T. mentagrophytes. In the co existence of i,inea pedis and tinea unguiurn, isolated species were corresponding. 3. Among 179 families, 143 families (79.9%) had at least one patient with tinea pedis. The isolated species of derrnatophytes in a farnily were one organism, 71.4% and two or more organisms, 28.6% of 77 familiys with more than one patient. Conclusion : In our study, the prevalence rate of tinea pedis was 41.2%. That suggests that tinea pedis is a wide spr .ad disease in healthy adult in Korea. (Kor J Dermatol 1997;35(1): 114-120)