• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.1
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• pp.7-11
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• 1998

In this paper, a new synapse cell with nonvolatile SONOS semiconductor memory device is proposed and it's fundamental function electronically implemented SONOS NVSM has shown characteristics that the memory value, synaptic weights, can be increased or decreased incrementally. A novel SONOS synapse is used to read out the stored analog value. For the purpose of synapse implementation using SONOS NVSM, this work has investigated multiplying characteristics including weight updating characteristics and neuron output characteristics. It is concluded that SONOS synapse cell has good agreement for use as a synapse in artificial neural networks.

• Electrical & Electronic Materials
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• v.8 no.5
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• pp.626-632
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• 1995

In this paper, The effect of the impedances in SNOSFET's memory devices has been developed. The effect of source and drain impedances measured by means of two bias resistances - field effect bias resistance by inner region, external bias resistance. The effect of the impedances by source and drain resistance shows the dependence of the function of voltages applied to the gate. It shows the differences of change in source drain voltage by means of low conductance state and high conductance state. It shows the delay of threshold voltages. The delay time of low conductance state and high conductance state by the impedances effect shows 3[.mu.sec] and 1[.mu.sec] respectively.

• Transactions on Electrical and Electronic Materials
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• v.4 no.5
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• pp.24-27
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• 2003

We have been investigated phase-change with temperature and electric field in chalcogenide Ge$_2$Sb$_2$Te$\sub$5/ thin film. T$\sub$c/(crystallization temperature) is confirmed by measuring the resistance with the varying temperature on the hotplate. We have measured I-V characteristics with Ge$_2$Sb$_2$Te$\sub$5/ chalcogenide thin film. It is compared with I-V characteristics after impress the variable pulse. The pulse has variable height and duration.

• Transactions on Electrical and Electronic Materials
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• v.15 no.1
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• pp.37-40
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• 2014

A novel memory is reported, in which $Ge_2Sb_2Te_5$ (GST) has been used as a floating gate. The threshold voltage was shifted due to the phase transition of the GST layer, and the hysteretic behavior is opposite to that arising from charge trapping. Finite Element Modeling (FEM) was adapted, and a new simulation program was developed using c-interpreter, in order to analyze the small shift of threshold voltage. The results show that GST undergoes a partial phase transformation during the process of RESET or SET operation. A large $V_{TH}$ shift was observed when the thickness of the GST layer was scaled down from 50 nm to 25 nm. The novel 1 transistor PCM (1TPCM) can achieve a faster write time, maintaining a smaller cell size.

• Proceedings of the Korean Information Science Society Conference
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• 2007.06b
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• pp.310-314
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• 2007

Log-Structured File system은 쓰기에 최적화한 파일 시스템으로 변경된 데이터를 최대한 모아서 순차적으로 기록하는 방식을 가지고 있다. 그러나 실제 시스템에서는 주기적인 동기화로 인해 작은 크기의 데이터들이 디스크로 쓰여지게 되면서 원래의 디자인 목표를 살리지 못하게 된다. 본 연구에서는 최근 급속도로 발전하고 있는 비휘발성 메모리(NVRAM)를 이용해서 주기적인 동기화를 없애고 작은 단위의 쓰기는 NVRAM을 통해 흡수하도록 하였다. 이를 통하여 DRAM만 있는 LFS에 비해 33% 가량 TPC-C 수행 성능이 향상되고, 더 빠르고 고른 응답 시간을 보일 수 있었다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.199-200
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• 2007

본 논문에서는 $SiO_2$ Gate 유전체를 대체할 재료의 하나인 $TiO_2$, Gate 유전체의 기판 증착 온도에 따른 특성을 알아보고자 한다. 디바이스의 고집적화가 높아짐에 따라 얇은 두께의 Gate 유전체의 절대적인 필요에 따라 두께를 최소화하면서 유전율은 높아 전기적 특성이 우수한 소재를 찾게 되었다. 본 논문의 실험에서는 비휘발성 메모리 소자 제작시 Gate Blocking Layer 적용을 위해 High-k 물질인 $TiO_2$, 박막 증착 실험을 하였고, APCVD 방법을 사용하여 성장하였다. 증착 온도에 따른 I-V 특성을 분석하고 그에 따른 소자의 물리적 구조를 SEM을 통해 확인하면서 소자 제작시 최적의 온도를 찾고자 하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.340-343
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• 2004

The phase transition between amorphous and crystalline states in chalcogenide semiconductor films can controlled by electric pulses or pulsed laser hem: hence some chalcogenide semiconductor films can be applied to electrically write/erase nonvolatile memory devices, where the low conductive amorphous state and the high conductive crystalline state are assigned to binary states. This letters researched into the characteristic of phase change transition in differential Chalcogenide thin films materials. The electrode used Al and experimented on 100nm, 300nm, 500nm respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.377-380
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• 2004

The phase transition between amorphous and crystalline states in chalcogenide semiconductor films can controlled by electric pulses or pulsed laser beam; hence some chalcogenide semiconductor films can be applied to electrically write/erase nonvolatile memory devices, where the low conductive amorphous state and the high conductive crystalline state are assigned to binary states. GeSbTe(GST), AsSbTe(AST), SeSbTe(SST) used to phase change materials by appling electrical pulses. Thickness of ternary chalcogenide thin films have about 100nm. Upper and lower electrode were made of Al. It is compared with I-V characteristics after impress the variable pulses.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.5
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• pp.840-845
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• 1998

This study was conducted to produce the high quality of chunggugjang. The taste compounds of chunggugjang produced with Bacillus subtilis DC-2, pigment producing bacterium, were analysed, and palatability of chunggugjang was compared to that of commercial chunggugjang. Among the volatile organic acids, the contentof acetic acid was contained more than any other volatile organic acid. The major nonvolatile organic acid was lactic acid, followed by oxalic acid and citric acid. Tartaric acid was not detected. In case of free sugars, raffinose was sharply decreased between 72 and 96 hours after fermentation. Free amino acid was increased to 20 folds at 48 hours after fermentation compared to that of stemed soybean. As a result of sensory test, it was founded that the chunggujang fermented by Bacillus subtilis DC-2 was suitable to produce for commercial purpose.

• Korean Journal of Food Science and Technology
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• v.26 no.6
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• pp.665-669
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• 1994

A rapid gas chromatographic (GC) profiling method was applied to dairy products (milk and cheeses) for the simultaneous analysis of volatile and nonvolatile organic acids. Cheese samples were first made into aqueous samples by dissolving in water. The aqueous samples were then extracted with organic solvents after the acidification and NaCI saturation. The organic layers (diethyl ether : hexane= 1 : 1) were extracted with $NaHCO_3$ saturated solution with subsequent solid-phase extraction of the aqueous phases using Chromosorb P column/diethyl ether followed by triethylamine treatment. The resulting triethylammonium salts of acids were directly converted into volatile tert.-butyldimethylsilyl derivatives, which were analyzed by dual-capillary column GC, and GC-mass spectrometry. From milk and four cheese samples studied, 31 organic acids including 21 fatty acids and other hydroxy and dioic acids were tentatively identified. The amounts of the fatty acids were different among the kinds of cheese and thus the simplified retention index (RI) spectra of organic acids were useful for the visual pattern recognition of each sample, when the Direct Comparision method between cheese and a blind sample were attempted, it was quickly recognized to be a gouda cheese with the 999 ppt match quality value.