AlN Epitaxial Film Growth Using MOCVD For a GHz-band FBAR

Chung-Mo Yang,Seong-Kweon Kim 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.55 No.3

We present the fabrication of a film-bulk-acoustic resonator (FBAR) with a highly c-axis- oriented AlN film on Mo/SiO2/Si (100) by using metal-organic chemical-vapor deposition (MOCVD). The resonant frequency and the anti-resonant frequency of the fabricated resonator were 3.219 GHz and 3.249 GHz, respectively. The quality factor and the effective electromechanical coupling coefficient (k2 eff ) were 24.7 and 2.65%, respectively. The conditions of AlN deposition were a substrate temperature of 950℃, a pressure of 20 Torr, and a V-III ratio of 25000. We successfully grew highly c-axis-oriented AlN film with 4 × 10−5 Ωcm resistivity for the Mo bottom electrode. The full widths at half maximum (FWHM) for the AlN (0002) deposited on Mo/SiO2/Si (100) and Mo/SiO2/Si (111) were 4˚ and 3.8˚, respectively. The FWHM value of the deposited AlN film meets the RF band-pass-filter specification for a GHz-band wireless local area network. We present the fabrication of a film-bulk-acoustic resonator (FBAR) with a highly c-axis- oriented AlN film on Mo/SiO2/Si (100) by using metal-organic chemical-vapor deposition (MOCVD). The resonant frequency and the anti-resonant frequency of the fabricated resonator were 3.219 GHz and 3.249 GHz, respectively. The quality factor and the effective electromechanical coupling coefficient (k2 eff ) were 24.7 and 2.65%, respectively. The conditions of AlN deposition were a substrate temperature of 950℃, a pressure of 20 Torr, and a V-III ratio of 25000. We successfully grew highly c-axis-oriented AlN film with 4 × 10−5 Ωcm resistivity for the Mo bottom electrode. The full widths at half maximum (FWHM) for the AlN (0002) deposited on Mo/SiO2/Si (100) and Mo/SiO2/Si (111) were 4˚ and 3.8˚, respectively. The FWHM value of the deposited AlN film meets the RF band-pass-filter specification for a GHz-band wireless local area network.

Mo/SiO₂/Si(100)기판 위에 MOCVD법으로 성장시킨 AIN박막이용 GHz대역의 FBAR제작에 관한 연구

양충모,김성권,차재상,박구만,Yang, Chung-Mo,Kim, Seong-Kweon,Cha, Jae-Sang,Park, Ku-Man 한국조명전기설비학회 2006 조명·전기설비학회논문지 Vol.20 No.4

본 논문에서는 $Mo/SiO_2/Si(100)$ 기판 위에 MOCVD(Metal-Organic-Chemical-Vapor Deposition)법을 이용하여 C축 방향으로 성장시킨 AIN(Aluminum Nitride) 박막을 이용하여 GHz대역 무선 통신에서 사용할 수 있는 FBAR(Film-Bulk-Acoustic Resonator)을 제작하였다. 제작된 공진부의 공진주파수와 반공진주파수는 각각 3.189[GHz]와 3.224[GHz]으로 측정되었으며, Q값(Quality Factor)과 유효한 전기기계 결합계수(${k_{eff}}^2$)는 각각 24.7과 2.65[%]로 평가되었다. AIN의 증착(Deposition) 조건은 $950[^{\circ}C]$의 기판표면(Substrate) 온도, 20Torr의 압력, 25000의 N/Al의 V/III비로 증착하였다. $4{\times}10^{-5}[\Omega{cm}]$의 Mo 하부전극 고유저항과 $Mo/SiO_2/Si(100)$ 기판 위에 AIN(0002) FWHM(Full-Width at Half-Maximum) 4를 갖는 C축 방향성의 AIN 박막을 성공적으로 성장시켰다. 따라서 증착된 AIN박막의 FWHM값은 GHz대역 무선 통신용 RF(Radio Frequency) 밴드 패스 필터 설계에 유용하게 사용될 것이다. In this paper, it is reported that film-bulk-acoustic resonator with high c-axis oriented AIN film on $Mo/SiO_2/Si(100)$ using metal-organic-chemical-vapor deposition was fabricated. The resonant frequency and anti-resonant frequency of the fabricated resonator were observed with 3.189[GHz] and 3.224[GHz], respectively. The quality factor and the effective electromechanical coupling coefficient(${k_{eff}}^2$) were measured with 24.7 and 2.65[%], respectively. The conditions of AIN deposition were substrate temperature of $950[^{\circ}C]$, pressure of 20Torr, and V-III ratio of 25000. A high c-axis oriented AIN film with $4{\times}10^{-5}[\Omega{cm}]$ resistivity of Mo bottom electrode and $4[^{\circ}]$ of AIN(0002) full-width at half-maximum(FWHM) on $Mo/SiO_2/Si(100)$ was grown successfully. The FWHM value of deposited AIN film is useful for the RF band pass filter specification for GHz-band wireless local area network.

Effects of epigallocatechin gallate on CoCl_(2)-induced apoptosis in PC12 cells

Yang, Kyu-Ho,Mo, Hyun-Chul,Choi, Nam-Ki,Kim, Seon-Mi,Kim,Won-Jae 大韓小兒齒科學會 2006 大韓小兒齒科學會誌 Vol.33 No.1

Neuronal apoptotic events, consequently resulting in neuronal cell death, are occurred in hypoxic/ischemic condition. This cell death has been shown to be accompanied with the production of reactive oxygen species (ROS), which can attack cellular components such as nucleic acids, proteins and phospholipid. However, the underlying mechanisms of apoptosis induced in hypoxic/ischemic condition and its treatment methods are unsettled. Cobalt chloride (CoCl_(2)) has been known to mimic hypoxic condition including the production of ROS. Epigallocatechin gallate (EGCG). a green tea polyphenol, has diverse pharmacologial activities in cell growth and death. This study was aimed to investigate the apoptotic mechanism by CoCl_(2) and effects of EGCG on CoCl_(2)-induced apoptosis in PC12 cells. Administration of CoCl_(2) decreased cell survival in dose- and time-dependent manners and induced genomic DNA fragmentation. Treatment with 100 µM EGCG for 30 min before PC12 cells were exposed to 150 µM CoCl_(2), being resulted in the cell viability and DNA fragmentation being rescued. CoCl_(2) caused morphologic changes such as cell swelling and condensed nuclei, whereas EGCG attenuated morphologic changes by CoCl_(2). EGCG suppressed the apoptotic peak and a loss of Δψ_(m) induced by CoCl_(2). CoCl_(2) decreased Bcl-2 expression but Bax expression was not changed in CoCl_(2)-treated cells. EGCG attenuated the Bcl-2 underexpression by CoCl_(2). CoCl_(2) augumented the cytochrome c release from mitochondria into cytoplasm and increased caspase-8, -9 and caspase-3 activity, a marker of the apoptotic executing stage. EGCG ameliorated the incruement in caspase-8, -9 and -3 activity, and cytochrome c release by CoCl_(2). NAC (N-acetyl-cysteine), a scavenger of ROS, attenuated CoCl_(2)-induced apoptosis in consistent with those of EGCG. These results suggest, that CoCl_(2) induces apoptotic cell death through both mitochondria- and death receptor-dependent pathway and EGCG has neuroprotective effects against CoCl_(2)-induced apoptosis in PC12 cells. 신경세포자멸사는 저산소 및 허혈환경에서 일어나며 이러한 세포죽은 reactive oxidant species (ROS) 생성을 동반함이 알려져있다. 그러나, 저산소 및 허혈환경에서 일어나는 세포자멸사의 기전 및 그 치료방법은 아직 정립되어 있지 않다. CoCl_(2)는 ROS를 생성하는 등 저산소환경과 유사한 조건을 초래하는 것으로 알려져 있다. Epigallocatechin gallate (EGCG)는 녹차의 polyphenol 성분으로서 세포성장과 죽음에 다양한 약리학적 효과를 나타냄이 알려져 있다. 본 연구는 PC12 세포에서 CoCl_(2)에 의한 세포자멸사기전을 밝히고 이에 미치는 EGCG의 효과를 조사하는데 목적이 있다. Cell viability는 MTT 측정으로 조사되었고, DNA fragmentation은 DNA laddering으로 조사되었다. Bcl-2와 Bax발현 정도는 RT-PCR로, caspase-3와 -9의 활성은 spectrophotometer, caspase-8의 활성은 flow cytometry에 의해 측정되었다. 미토콘드리아에서 세포질로 분비된 cytochrome c는 western blot으로, 분해된 DNA 양과 미토콘드리아 세포막전위 (Δψ_(m))는 FACScan으로 조사되었다. CoCl_(2)투여로 PC12 세포수는 용량 및 시간 의존형태로 감소하였고, genomic DNA fragmentation이 발생하였다. CoCl_(2)투여로 야기된 cell viability의 감소와 DNA fragmentation은 EGCG 전처치에 의해 억제되었다. CoCl_(2)은 세포용적팽창과 condensed nuclei 같은 형태적 변화를 일으켰으며, apoptotic peak, Δψ_(m)감소 및 cytochrome c 유리를 야기하였다. EGCG는 CoCl_(2)에 의한 세포형태변화, apoptotic peak, Δψ_(m)소실 및 cytochrome c 유리를 억제시켰다. CoCl_(2)는 Bcl-2 발현을 감소시켰지만, Bax 발현에는 영향을 미치지 않았다. EGCG는 CoCl_(2)에 의해 야기된 Bcl-2 발현 감소를 억제시켰다. CoCl_(2)는 caspase-3, -8, 그리고 -9의 활성을 증가시켰으며, EGCG는 CoCl_(2)에 의한 세포자멸사를 억제시켰다. 본 실험결과는 PC12 세포에서 CoCl_(2)가 미토콘드리아 의존 및 death receptor의존 기전으로 세포자멸사를 일으키며, EGCG는 세포자멸사기전을 억세지킴으로 신경보호기능을 가짐을 시사하였다.

Goethe의 사유형식에 관한 고찰

양인모 ( In Mo Yang ) 한국독어독문학교육학회 1989 獨語敎育 Vol.7 No.-

원심압축기의 선회실속특성에 관한 연구

모양우,나기대,유영태,김지환 朝鮮大學校 機械技術硏究所 2003 機械技術硏究 Vol.6 No.2

In the present study, the performance characteristics and the number of stall cell during rotating stall of a centrifugal air compressor were experimentally investigated. Rotating stall in the vaneless diffuser were investigated by measuring unsteady pressure fluctuations at several different diffuser radius using a high frequency pressure transducer. The number of stall cell and their rotational speeds are distinctive features of the rotating stall phenomenon. The present study is mainly forced on the analysis for the stall cell number and its propagation speed unstable operating region of the compressor. The interpretation method of visualization is based on the pressure distribution in the circumference pressure fields while plotting the pressure and its harmonics variations in time in polar coordinates. To obtain the visualize the existence rotating stall, auto-correlation function and the frequency spectra of the pressure fluctuations were measured at rh-2 = 1.52. When the flow coefficient is lower than 0.150, the static pressure at impeller inlet is higher than that at inlet duct of the Compressor. And the flow coefficient is lower than 0.086, several stall cell groups of discrete frequencies are observed.

유압관로의 비정상유동에 따른 임피던스 전달특성

모양우,유영태,나기대,김지환 한국공작기계학회 2004 한국생산제조학회지 Vol.13 No.6

Design for quite operation of fluid power system requires the understanding of noise and vibration characteristics of the system. This paper presents a dynamic response of design of hydraulic circuit. Experimental investigations on the attenuation of pressure ripple in automotive power steering hydraulic pipe line is examined. Also, a mathematical model of hydraulic pipe is proposed to support a design of the hydraulic circuit. and the impedance characteristics of pressure ripple is analyzed. It is experimentally shown that power steering hydraulic pipe attenuates pressure ripple with high frequency.

우리나라 제약산업의 경쟁력 강화

양봉민,이모세 서울大學校 保健大學院 1998 보건학논집 Vol.35 No.1

With economic crisis in 1998, Korean pharmaceutical industry faces a new challenge for a change. The challenge began in 1987, when the IPR (intellectual property right) was enforced in the area of pharmaceutical products by the developed countries. Domestically, the challenge is related with the cost containment of pharmaceutical industry, analyzes problems that the industry is facing these days, and suggests future strategies for the industry to be competitive in the international market. Efforts to increase M&A among pharmaceutical firms are recommended as potential strategies.

直角變調의 AM 多重通信方法에 있어서의 位相偏移에 관한 硏究

金良模 충남대학교 공업교육연구소 1982 論文集 Vol.5 No.1

We analysed the Harris' s system, one of the AM stereo broadcasting systems, and derived the boundaries of the distortion and RC time constant to the phase shifts of both sidebands in the envelope detector of the existing monaural radio receiver. In that result, we obtained that the approximate distortion was secθ/2-1 and the maximum RC time constant of envelope detector was 35.3×tanθ(μsec).

임신중 뇌동맥류의 외과적 치료 : 증례보고 A Case Report

이익모,김상진,박순필,도종웅,주양자 대한신경외과학회 1988 Journal of Korean neurosurgical society Vol.17 No.1

A multiparous 28-year-old woman, suffering ruptured intracranial aneurysm during pregnancy is presented. Clipping of the aneurysm was performed in 32 weeks of gestational age. Three weeks after operation, she delivered vaginally without complication. Delivery may be managed according to obstetrical indication following surgical correction of the aneurysm. The authors reviewed the literature, and discussed the neurosurgical and obstetric management of such patients.

物質特許導入前後 醫藥品市場의 構造變化에 관한 硏究

이모세,양봉민 서울大學校保健大學院 1995 國民保健硏究所硏究論叢 Vol.5 No.2

This study intended to investigate change in pharmaceutical market structure in relation to the introduction of product patent protection in Korea. The ultimate purpose of this study is to help the government seek the ways of improving pharmaceutical social benefit. The main results of this study is as follows; Concentration ratios decreased in total pharmaceutical market but has increased or decreased in therapeutic markets since the introduction of product patent protection in Korea. The share of multinational and cooperative enterprises had sharply increased 21.1% in 1989 to 29.7% in 1994 in hospital pharmaceutical market. On the contrary it had decreased a little in pharmacy pharmaceutical market, 10.9% in 1989 to 9.4% in 1994. Accordingly the introduction of product patent protection and its impact have resulted in change in pharmaceutical market structure of Korea. They have forced the total pharmaceutical market to be competitive. But it maybe force therapeutic market to be monopolic. The government policies on pharmaceutical products have to be directed to improve pharmaceutical socialbenefits with regard to these aspects.