• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1992년도 하계학술대회 논문집 B
• /
• pp.806-808
• /
• 1992

This paper describes a buried-island SOI MOSFET structure which can reduce the edge channel effect by improving the interface properties at the side wall of active island and by reducing the strength of electric field applied at the upper corner of the side wall from the gate. Also, the buried-island SOl structure can obtain the uniform thickness of SOl film. The buried-island structure can be achieved by Zone- Melting-Recrystallization of polysilicon and polishing. Both simulated and experimental results show that the buried-island SOl NMOSFET has less edge channel effect than the conventional SOl NMOSFET using LOCOS or mesa isolation technique.

• Journal of Korean Neurosurgical Society
• /
• 제44권5호
• /
• pp.285-294
• /
• 2008

Objective: Jugular foramen schwannomas are uncommon pathological conditions. This article is constituted for screening these tumors in a wide perspective. Materials: One-hundred-and-ninty-nine patients published in 19 articles between 1984 to 2007 years was collected from Medline/Index Medicus. Results: The series consist of 83 male and 98 female. The mean age of 199 operated patients was 40.4 years. The lesion located on the right side in 32 patients and on the left side in 60 patients. The most common presenting clinical symptoms were hearing loss, tinnitus, disphagia, ataxia, and hoarseness. Complete tumor removal was achieved in 159 patients. In fourteen patients tumor reappeared unexpectedly. The tumor was thought to originate from the glossopharyngeal nerve in forty seven cases; vagal nerve in twenty six cases; and cranial accessory nerve in eleven cases. The most common postoperative complications were lower cranial nerve palsy and facial nerve palsy. Cerebrospinal fluid leakage, meningitis, aspiration pneumonia and mastoiditis were seen as other complications. Conclusion: This review shows that jugular foramen schwannomas still have prominently high morbidity and those complications caused by postoperative lower cranial nerve injury are life threat.

• 전자공학회논문지A
• /
• 제29A권10호
• /
• pp.29-34
• /
• 1992

JFET's with gate lengths ranging from 1$\mu$m to 8.3$\mu$m are successfully fabricated on InP substrate where the long haul (1.3$\mu$m~8.3$\mu$m) OEIC's(OptoElectronic Integrated Circuits) have been made. The pn junction of InP JFET's is made by co-implantation and RTA process. JFET's have etched-mesa-gate structure and the maximum gm larger than 90mS/mm was measured and this is the highest record in JFET's of such structure without S/D n$^{+}$ ion implantation. To maintain maximum g$_m$ should be well controlled the overetch of n-layer which inevitably occurs during etching off the unused p-layer. The I-V characteristic is checked during p-layer etch, for this purpose. A dc voltage gain of 11 is obtained from a preamplifier circuit thus fabricated.

• 천문학회보
• /
• 제41권2호
• /
• pp.53.2-53.2
• /
• 2016

We present our experiences with open-source spatio-temporal database systems for managing and analyzing big astronomical data acquired by wide-field time-domain sky surveys. Considering performance, cost, difficulty, and scalability of the database systems, we conduct comparison studies of open-source spatio-temporal databases such as GeoMesa and PostGIS that are already being used for handling big geographical data. Our experiments include ingesting, indexing, and querying millions or billions of astronomical spatio-temporal data. We choose the public VVV (VISTA Variables in the Via Lactea) catalogs of billions measurements for hundreds of millions objects as the test data. We discuss issues of how these spatio-temporal database systems can be adopted in the astronomy community.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2002년도 하계학술대회 논문집
• /
• pp.206-209
• /
• 2002

With the progress of semiconductor processing technology, avalanohe photodiodes (APDs) based on InP/InGaAs are used for high-speed optical receiver modules. Planar-type APDs give higher reliability than mesa-type APDs. However, Planar-type APDs are struggled with a problem of intensed electric field at the junction curvature, which causes edge breakdown phenomena at the junction periphery. In this paper, we focused on studying the effects of junction curvature for APDs performances by different etching processes followed by single diffusion to from p-n junction. The performance of each process is characterized by observing electric field profiles and carrier generation rates. From the results, it can be understood to predict the optimum structure, which can minimize edge breakdown and improve the manufacturability.

• 전자공학회논문지A
• /
• 제32A권1호
• /
• pp.129-137
• /
• 1995

AlGaAs/GaAs HBTs have been fabricated using SABM (Self-Aligned Base Metal) process technique. The mesa type HBTs were fabricated through following steps: isolation implant, wet etching, metal lift-off, and airbridge interconnection process. The fabricated HBTs with 2umx10um size emitter showed a common emitter current gain of 10 at a collector current density of Jk=100kA/cm$^{2}$, a breakdown volgate BVCEO of 8V, and the ideality factors of base and collector junctions of 1.6 and 1.1, respectively. On-wafer S-Parameter measurement at 0.5~18GHz has been made for the characterization of the common emitter HBTx with a 2umx10um size emitter. The extrapolated current gain cut-off frequency of ft=30GHz and maximum oscillation frequency of fmax=23 GHz were obtained at a collector current density of Jc=70kA/cm$^{2}$. Small signal HBT equivalent circuit was extracted from the S-Parameter data.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2001년도 하계종합학술대회 논문집(2)
• /
• pp.189-192
• /
• 2001

We have studied fabrication processes that form asymmetric $\Gamma$-gate with a 0.1${\mu}{\textrm}{m}$ gate length in MMIC's(Monolithic Microwave Integrated Circuits). Asymmetric $\Gamma$-gate was fabricated using mixture of PMMA and MCB. Thus pseudomorphic high electron mobility transistor (PHEMT's) with 0.1${\mu}{\textrm}{m}$ gate length was fabricated via several steps such as mesa isolation, metalization, recess, passivation. PHEMT's has the -1.75 V of pinch-off voltage (Vp), 63 mA of drain saturation current(Idss and 363.6 mS/mm of maximum transconductance (Gm) in DC characteristics and current gain cut-off frequency of 106 GHz and maximum frequency of oscillation of 160 GHz in RF characteristics.

• 전자공학회논문지A
• /
• 제33A권6호
• /
• pp.164-171
• /
• 1996

We report the experimental resutls on AlGaAs/GaAs heterojunction bipolar transistors (HBTs) with carbon-doped base structure. To characterize the output power, load-pull mehtod was employed. By characterizing the devices with HP8510C, we extracted the small-signal equivalent circuit. The HBTs were fabricated employing wet mesa etching and lift-off process of ohmic metals. the implementation of polyimide into the fabriction process was accomplished to obtain the lower dielectric constant resultig in significant reduction of interconnect routing capacitance. The fabricated HBTs with an emitter area of 6${\times}14{\mu}m^{2}$ exhibited current gain of 45, BV$_{CEO}$ of 10V, cut-off frequency of 30GHz and power gain of 1 3dBm. To extract the small signal equivalent circuit, the de-embedded method was applied for parasitic parameters and the calculation of circuit equations for intrinsic parameters.

• 한국연초학회지
• /
• 제5권2호
• /
• pp.47-54
• /
• 1983

Tobacco leaves cultivated in Korea, U.S A., Greece and Turkey were analyzed for their essential oils that are solanone, nor- solanadione, damascenone, dana scone and mesa stigmatrienone (4- isomer). Regardless of tobacco varieties and cultivated localities, solanone was the most abundant. Among them particularly, Basma has the highest amounts of the solanone than other varieties. Flue-cured tobacco leaf has much higher amounts of damascellone than burley and aromatic tobacco leaf do. U.S. A. flue-cured, U.S. A. burley and Basma clave much higher concentration of solanone than corresponding Korean varieties, but significant differences could not be observed in other components. The order of total amounts of 8 essential oils in tobacco varieties were as follows; Aromatic) Burley) Flue-cured

• 전자공학회논문지D
• /
• 제34D권7호
• /
• pp.15-22
• /
• 1997

A 10Gbit/s limiting amplifier IC for optical transmission system was implemented with AlGaAs HBT (heterojunction bipolar transistor) technology. HBTs with 2x10.mu. $m^{2}$ and 6x20.mu. $m^{2}$ emitter size were used. The HBT structures are based on metal-organic chemical vapor deposition (MOCVD) epitxy and employ a mesa structure with self-aligned emitter/base and sidewall dielectric passivation. IC was designed to support differnetial input and output. Small signal performance of the packaged IC showed 26dB gain and $f_{3dB}$ of 8GHz. A single ouput has 800m $V_{p-p}$ swing with more than 26dB dynamic range. The performance of the limiting amplifier was verified through single mode fiber320km transmission link test.est.