• Journal of the Semiconductor & Display Technology
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• v.23 no.1
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• pp.110-116
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• 2024

Despite the continuous advancement of science and technology, fire accidents continue to occur without decreasing over time, so there is a constant need for a system that can accurately detect fires at an early stage. However, because most existing fire detection systems detect fire in the early stage of combustion when smoke is generated, rapid fire prevention actions may be delayed. Therefore we propose an early fire detection system that can perform early fire detection at a reasonable cost using LSTM, a deep learning model based on multi-gas sensors with high selectivity in the early stage of decomposition rather than the smoke generation stage. This system combines multiple gas sensors to achieve faster detection speeds than traditional sensors. In addition, through window sliding techniques and model light-weighting, the false alarm rate is low while maintaining the same high accuracy as existing deep learning. This shows that the proposed fire early detection system is a meaningful research in the disaster and engineering fields.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.245-247
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• 1987

In this thesis, ZnO semiconductor gas sensors doped by the $Al^{3+}$ were fabricated by the miexed oxide method. The specimens were sintered for 5(hr) at $1000-1200^{\circ}C$ and the I-V, sensitivity were investigated in acetone gas or ammonia gas. As a result, I-V curves of specimens as a function of temperature variation showed characteristics of linear resistor that the current was proportional to the, temperature at constant voltage. For the sensitivity of acetone, 1Wt $Al^{3+}$-ZnO has the hight 0.91, ammonia gas, 2Wt $Al^{3+}$-ZnO specimen has the hight 0.90. Hence, the operating temperature of specimens were both $300^{\circ}C$.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2002.06a
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• pp.356-360
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• 2002

Polluting the air with such pollutants as CO, H₂S and SO₂, industrial development huts increased the danger of gas toxication. Futhermore, as the: living standard goes higher, the consumption of explosive hydrocarbonic gases such as butane(C₄H/sub 10/) or propane(C₃H/sub 8/) has been soaring, which results in the danger of a gas explosion. As measures to cope with such dangers, the development of highly sensitive gas sensors, gas detectors adopting gas-sensing technologies, and gas recognition systems are urgently required. The objective of the present research is to develop a gas recognition system that is capable of identifying specific types of selected gases by formulating a semiconductor-typed gas sensor array, which not only improves the selectivity of semiconductor-typed gas sensors but also minimizes the erect of drifts on a single sensor signal, and applying the input pattern data of gases detected by the array to a neural network.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.3
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• pp.705-711
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• 2000

A thin film oxide semiconductor micro gas sensor array which shows only 60 mW of power consumption at an operating temperature of $300^{\circ}C$ has been fabricated using microfabrication and micromachining techniques. Excellent thermal insulation of the membrane is achieved by the use of a double-layer structure of $0.1\mum\; thick\; Si_3N_4 \;and\; 1 \mum$ thick phosphosilicate glass (PSG) prepared by low-pressure chemical-vapor deposition (LPCVD) and atmospheric-pressure chemical-vapor deposition (APCVD), respectively. The sensor array consists of such thin film oxide semiconductor sensing materials as 1 wt.% Pd-doped $SnO_2,\; 6 wt.% A1_2O_3-doped\; ZnO,\; WO_3$/ and ZnO. Baseline resistances of the four sensing materials were found to be stable after the aging for three days at $300^{\circ}C$. The thin film oxide semiconductor micro gas sensor array exhibited resistance changes usable for subsequent data processing upon exposure to various gases and the sensitivity strongly depended on the sensing layer materials.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.2
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• pp.315-322
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• 2002

A thin film oxide semiconductor micro gas sensor array which shows only 60㎽ of power consumption at an operating temperature of 30$0^{\circ}C$ has been fabricated using microfabrication and rnicrornachining techniques. Excellent thermal insulation of the membrane is achieved by the use of a double la! or structure of 0.1${\mu}{\textrm}{m}$ thick Si$_3$N$_4$ and 1${\mu}{\textrm}{m}$ thick phosphosilicate glass(PSG) prepared by low pressure chemical vapor deposition(LPCVD) and atmospheric－pressure chemical-vapor deposition(APCVD), respectively. The sensor way consists of such thin film oxide semiconductor sensing materials as 1wt.％ Pd-doped SnO$_2$, 6wt.% AI$_2$O$_3$-doped ZnO, WO$_3$ and ZnO. The thin film oxide semiconductor micro gas sensor array exhibited resistance changes usable for subsequent data processing upon exposure to various gases and the sensitivity strongly depended on the sensing layer materials. Heater Part of the sensor structure has been modified in order to improve the process yield of the sensor, and as a result of modified heater structure improved process yield has been achieved.

• Journal of IKEEE
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• v.17 no.4
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• pp.531-536
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• 2013

The impact of UV irradiation process on the AlGaN/GaN metal-oxide-semiconductor heterostructure field-effect transistor was investigated. Due to the high intensity UV irradiation before the gate dielectric deposition, the conductivity of AlGaN/GaN structure and the drain saturation current of the transistor increased by about 10 %. However, the pinch off characteristics of transistor was severely deformed by the process. By comparing the electrical characteristics of the transistors, it was proposed that the high intensity UV irradiation formed a sub-channel under the two dimensional electron gas of AlGaN/GaN structure even without additional impurity injection.

• Clean Technology
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• v.5 no.1
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• pp.62-77
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• 1999

Semiconductor industry has rapidly grown because of the need from electronic and computer industries. However the global environmental regulations for various hazardous chemical compounds, which are indispensably used in semiconductor manufacturing process, are getting stronger. The semiconductor industries should develop the cleaner technologies in order to both lead the future world market and avoid the regulations form environmentally developed countries. In this paper, cleaner technologies for semiconductor cleaning processes are surveyed, such as gas phase process, UV process, and plasma process. Advantages and disadvantages of these processes are discussed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.62-64
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• 2021

This paper relates to an improved method for using an semiconductor sensor. Although the basic usage of the commonly used semiconductor sensor is known, the data measured according to each usage method is limited in terms of use due to poor accuracy and stability. We propose a method to improve stability and accuracy by improving the method of use according to the characteristics of the semiconductor sensor.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.251-252
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• 2012

Recently, the growing interest in organic microelectronic devices including OLEDs has led to an increasing amount of research into their many potential applications in the area of flexible electronic devices based on plastic substrates. However, these organic devices require a gas barrier coating to prevent the permeation of water and oxygen because organic materials are highly susceptible to water and oxygen. In particular, high efficiency OLEDs require an extremely low Water Vapor Transition Rate (WVTR) of $1{\times}10^{-6}g/m^2$/day. The Key factor in high quality inorganic gas barrier formation for achieving the very low WVTR required ($1{\times}10^{-6}g/m^2$/day) is the suppression of defect sites and gas diffusion pathways between grain boundaries. In this study, we developed an $Al_2O_3$ nano-crystal structure single gas barrier layer using a Neutral Beam Assisted Sputtering (NBAS) process. The NBAS system is based on the conventional RF magnetron sputtering and neutral beam source. The neutral beam source consists of an electron cyclotron Resonance (ECR) plasma source and metal reflector. The Ar+ ions in the ECR plasma are accelerated in the plasma sheath between the plasma and reflector, which are then neutralized by Auger neutralization. The neutral beam energies were possible to estimate indirectly through previous experiments and binary collision model. The accelerating potential is the sum of the plasma potential and reflector bias. In previous experiments, while adjusting the reflector bias, changes in the plasma density and the plasma potential were not observed. The neutral beam energy is controlled by the metal reflector bias. The NBAS process can continuously change crystalline structures from an amorphous phase to nano-crystal phase of various grain sizes within a single inorganic thin film. These NBAS process effects can lead to the formation of a nano-crystal structure barrier layer which effectively limits gas diffusion through the pathways between grain boundaries. Our results verify the nano-crystal structure of the NBAS processed $Al_2O_3$ single gas barrier layer through dielectric constant measurement, break down field measurement, and TEM analysis. Finally, the WVTR of $Al_2O_3$ nano-crystal structure single gas barrier layer was measured to be under $5{\times}10^{-6}g/m^2$/day therefore we can confirm that NBAS processed $Al_2O_3$ nano-crystal structure single gas barrier layer is suitable for OLED application.

• 한국가스학회:학술대회논문집
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• 1997.09a
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• pp.292-301
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• 1997