• 한국전기전자재료학회논문지
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• 제21권4호
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• pp.296-299
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• 2008

The effects of radio frequency (RF) source power for decoupled plasma nitridation (DPN) process on the electrical properties and Fowler-Nordheim (FN) stress immunity of the oxynitride gate dielectrics for deep nano-technology devices has been investigated. With increase of RF source power, the threshold voltage (Vth) of a NMOS transistor(TR) decreased and that of a PMOS transistor increased, indicating that the increase of nitrogen incorporation in the oxynitride layer due to higher RF source power induced more positive fixed charges. The improved off-current characteristics and wafer uniformity of PMOS Vth were observed with higher RF source power. FN stress immunity, however, has been degenerated with increasing RF source power, which was attributed to the increased trap sites in the oxynitride layer. With the experimental results, we could optimize the DPN process minimizing the power consumption of a device and satisfying the gate oxide reliability.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.307-307
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• 2013

초고집적 회로에 적용되는 반도체 소자의critical dimension (CD)이 수 nano 사이즈로 줄어들고 있기 때문에, 다양한 물질의 식각을 할 때, 건식식각의 중요성이 더 강조되고 있다. 특히 $SiO_2$와 같은 유전체 물질을 식각할 때, plasma process induced damages (P2IDs)가 관찰되어 왔고, 이러한 P2IDs를 줄이기 위해, pulsed-time modulation plasma가 광범위하게 연구되어 왔다. Pulsed plasma는 정기적으로 radio frequency (RF) power on과 off를 반복하여 rf power가 off된 동안, 평균전자 온도를 낮춤으로써, 웨이퍼로 입사되는 전하 축적을 효과적으로 줄일 수 있다. 또한 fluorocarbon plasmas를 사용하여 $SiO_2$를 식각하기 위해 Dual-Frequency Capacitive coupled plasma (DF-CCP)도 널리 연구되어 왔는데, 이것은 기존의 방법과는 다르게 plasma 밀도와 ion bombardment energy를 독립적으로 조절 가능하다는 장점이 있어서 미세 패턴을 식각할 때 효과적이다. 본 연구에서는 Source power에는 60 MHz pulsed radio frequency (RF)를, bias power에는 2 MHz continuous wave (CW) rf power가 사용된 system에서 Ar/$C_4$ F8/$O_2$ 가스 조합으로, amorphous carbon layer (ACL)가 hard mask로 사용된 $SiO_2$를 식각했다. 그리고 source pulse의 duty ratio와 pulse frequency의 효과에 따른 $SiO_2$의 식각특성을 연구하였다. 그 결과, duty ratio의 감소에 따라 $SiO_2$, ACL의 etch rate이 감소했지만, $SiO_2$/ACL의 etch selectivity는 증가하였다. 반면에 pulse frequency의 변화에 따른 두 물질의 etch selectivity는 크게 변화가 없었다. 그 이유는 pulse 조건인 duty ratio의 감소가 전자 온도 및 전자 에너지를 낮춰 $C_2F8$가스의 분해를 감소시켰으며, 이로 인해 식각된 $SiO_2$의 surface와 sidewall에 fluorocarbon polymer의 형성이 증가하였기 때문이다. 또한 duty ratio의 감소에 따라 etch selectivity뿐만 아니라 etch profile까지 향상되는 것을 확인할 수 있었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 C
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• pp.1913-1916
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• 1996

With a progress of electrical and electronic technology, radio-frequency circuits including high frequency components are widely applied to various industrial installations. Some of them are used in hazardous locations where explosive or flammable gases exist. As a result, ignition of such gases may be induced by a spark discharge when the radio frequency circuits are switched on or off. The purpose of this study is to investigate the ignition hazards of acetylene-air and ethylen-air mixtures experimentally based on the IEC 79-3 publication. In this experiment, we used a high frequency resistive circuit which consists of a co-axial cable, a $10{\Omega}$, $20{\Omega}$, $30{\Omega}$, $40{\Omega}$ or $50{\Omega}$ resistor and a power amplifier with frequency range up to almost 1 MHz. Experimental results show that the ignition of the acetylene-air and ethylen-air mixtures due to spark discharge depends primarily on the frequency of the power source in the resistive circuit: the minimum ignition voltage increases gradually with the increase of the frequency.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.157.1-157
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• 2001

A new methodology is presented to diagnose faults in equipment plasma. This is accomplished by using neural networks as a pattern recognizer of radio frequency(rf) impedance match data. Using a realtime match monitor system, the match data were collected. The monitor system consisted mainly of a multifunction board and a signal flow diagram coded by Visual Designer. Plasma anomaly was effectively represented by electrical match positions. Twenty sets of fault-symptom patterns were experimentally simulated with experimental variations in process factors, which include rf source power, pressure, Ar and O$_2$ flow rates. As the inputs to neural networks, two means and standard deviations of positions were used ...

• 반도체디스플레이기술학회지
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• 제22권2호
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• pp.64-71
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• 2023

If an impedance mismatch occurs between the source and load in a Radio Frequency transmission system, reflected power is generated. This results in incomplete power transmission and the generation of Reflected Power, which returns to the Radio Frequency generator. To minimize this Reflected Power, Impedance matching is performed. Fast and efficient Impedance matching, along with converging reflected power towards zero, is advantageous for achieving desired plasma characteristics in semiconductor processes. This paper explores Impedance matching by adjusting the Vacuum Variable Capacitor of an L-type Matching Module based on the trends observed in the voltage of the Phase Sensor and Electromotive Force voltage. After assessing the impedance matching characteristics, the findings are described.

• 한국안전학회지
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• 제27권4호
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• pp.26-32
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• 2012

With a progress of electrical and electronic technology, radio-frequency including high frequency components are widely to various industrial installations. Some of them are used in hazardous locations where explosive or flammable gases exist. As a result, ignition of such gases may be induced by a spark discharge when the radio frequency circuits are switched on or off. The purpose of this study is to investigate the ignition hazards of some kind of flammable mixtures based on the IEC 60079-11 publication. In this experiment, we used a high frequency resistive circuit which consists of a co-axial cable, a 20 ${\Omega}$, 30 ${\Omega}$, 40 ${\Omega}$ and 50 ${\Omega}$ resistor and two kind of power amplifier with frequency range up to almost 1 MHz and 50 MHz. Experimental results show that the ignition of the acetyleneair, ethylene-air mixtures and methane-air mixtures due to spark discharge depends primarily on the frequency of the power source in the resistive circuit the minimum ignition voltage increases gradually with the increase of the frequency.

• 한국진공학회지
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• 제8권3B호
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• pp.368-375
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• 1999

The Maxwell equation and the transformer equivalent-circuit model are applied to a radio frequency planar inductively coupled plasma. The spatial distribution of the vector potential, the magnetic field, and the electric field are obtained analytically. As a result, the plasma current, the mutual inductance between the coil and the plasma, and the self inductance of plasma are found to increase with increasing skin depth. The spatial distribution of absorbed power has maximum where the antenna coil exists, and has a similar profile to that of the induced electric field. The power transfer efficiency is found to increase with increasing gas pressure before a saturation around p+ 20mTorr, while it shows an increase with the plasma density before a slight decrease around a density of $5\times10^{11}/\textrm{cm}^3$.

• Journal of electromagnetic engineering and science
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• 제6권1호
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• pp.76-81
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• 2006

Ultra wideband(UWB) technologies have been developed to exploit a new spectrum resource in substances and to realize ultra-high-speed communication, high precision geo-location, and other applications. The energy of UWB signal is extremely spread from near DC to a few GHz. This means that the interference between conventional narrowband systems and UWB systems is inevitable. However, the interference effects had not previously been studied from UWB wireless systems to conventional wireless systems sharing the frequency bands such as Broadcasting system. This paper experimentally evaluates the interference from two kinds of UWB sources, namely a orthogonal frequency division Multiplex UWB source and an impulse radio UWB source, to a Broadcasting transmission system. The receive power degradations of broadcasting system are presented. From these experimental results, we show that in all practical cases UWB system can coexist 35 m distance in-band broadcasting network.

• 한국위성정보통신학회논문지
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• 제7권1호
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• pp.39-47
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• 2012

현재의 주파수 분배상황을 살펴보면 대부분의 주파수 대역이 고정 할당되어 있으며 특히 무선통신 환경에 가장 적합한 저주파 대역은 거의 사용할 여지가 없다. 이에 인지무선 기술은 무선통신환경에서 주파수 부족 문제를 해결하고 주파수 활용도를 높이기 위한 중요한 기술로 대두되고 있다. 본 논문에서는 SDR (Software Define Radio)플랫폼인 USRP (Universal Software Radio Peripheral) 보드와 SDR 개발 툴킷인 GNU Radio를 이용하여 실제 인지무선(Cognitive Radio : CR) 시스템에서 데이터를 송, 수신하였다. 구체적으로 스펙트럼 센싱 기술을 이용하여 면허 사용자의 주파수 사용 여부를 감지하여 이 정보를 데이터베이스로 넘겨준다. 정보를 넘겨받은 데이터베이스에서는 유전자 알고리즘을 이용하여 최적의 송신전력과 대역폭, 채널 정보를 인지무선 기기에 보내어 주어 인지무선 기기가 면허 사용자에게 아무런 간섭을 주지 않고 데이터 통신을 할 수 있도록 하였다.

• KIEE International Transactions on Electrophysics and Applications
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• 제2C권5호
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• pp.246-252
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• 2002

Two-dimensional steady state simulations of planar type radio frequency inductively coupled plasma (RFICP) have been performed. The characteristics of RFICP were investigated in terms of power transfer efficiency, equivalent circuit analysis, spatial distribution of plasma density and electron temperature. Plasma density and electron temperature were determined from the equations of ambipolar diffusion and energy conservation. Joule heating, ionization, excitation and elastic collision loss were included as the source terms of the electron energy equation. The electromagnetic field was calculated from the vector potential formulation of ampere's law. The peak electron temperature decreases from about 4eV to 2eV as pressure increases from 5 mTorr to 100 mTorr. The peak density increases with increasing pressure. Electron temperatures at the center of the chamber are almost independent of input power and electron densities linearly increase with power level. The results agree well with theoretical analysis and experimental results. A single turn, edge feeding antenna configuration shows better density uniformity than a four-turn antenna system at relatively low pressure conditions. The thickness of the dielectric window should be minimized to reduce power loss. The equivalent resistance of the system increases with both power and pressure, which reflects the improvement of power transfer efficiency.