• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.8 s.99
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• pp.777-782
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• 2005

In this paper, adaptive bias circuit and PBG structure have been employed to suppress IMD(Inter-Modulation Distortion) and improve PAE(Power Added Efficiency) of the Doherty amplifier. Gate bias voltage has been controlled with the envelope of the input RF signal and PBG structure has been employed on the output port of Doherty amplifier. The proposed power amplifier using adaptive bias circuit and PBG has been improved the $IMD_3$ by 7.5 dBc, and the average PAR by $12\%$, respectively.

• Analytical Science and Technology
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• v.7 no.2
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• pp.155-164
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• 1994

A conventional Grimm-type glow discharge source was constructed and applied to radio-frequency(13.56MHz) discharge for metal and ceramic analysis. We investigated the emission spectrum for aluminium and aluminium oxide and the influence of discharge operating paramaters including argon pressure, rf-power and DC-bias voltages at the sample-side electrode. Scanning Electron Microscope(SEM) also was used to investigate the effect of rf-sputtering on the microstructure formation of the aluminium oxide. Linear analytical calibration curves were constructed for Manganese and zinc element in samples of low alloy steel(BAS 401-405) and brass(NIST 1108-1117).

• Journal of the Korean Institute of Telematics and Electronics A
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• v.28A no.11
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• pp.894-901
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• 1991

Contact-type linear image sensors have been fabricated by means of RF glow discharge decomposition method of silane and hydrogen mixtures. The dependences of the electrical and optical properties of these sensor on thickness, RF power, substrate temperature and ambient gas pressure have been investigated. the ITO/i-a-Si:H/Al structure film shows photosensitivity of 0.85 and photocurrent to dark current ratio ($I_{ph}/I_{d}$) of 150 at 5V bias voltage under 200${\mu}W/cm^[2}$ red light intensity. Under 200${\mu}W/cm^[2}$ green light intensity, the ratio is 100. In order to investigate photocarrier transport mechanism and to obtain ${\mu}{\gamma}$ product we have measured the I-V characteristics of these sensors favricated with several different deposition parameters under various light sources. The linear inage sensor for document reading has been operated under reverse bias condition with green light source, resulting in ${\mu}{\gamma}$ product of about 1.5$[\times}10^{-9}cm^{2}$/V.

• Journal of the Korean institute of surface engineering
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• v.42 no.6
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• pp.251-255
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• 2009

In this study, the plasma etching of the TaN thin film with $O_2/BCl_3$/Ar gas chemistries was investigated. The equipment for the etching was an inductively coupled plasma (ICP) system. The etch rate of the TaN thin film and the selectivity of TaN to $SiO_2$ and PR was studied as a function of the process parameters, including the amount of $O_2$ added, an RF power, a DC-bias voltage and the process pressure. When the gas mixing ratio was $O_2$(3 sccm)/$BCl_3$(6 sccm)/Ar(14 sccm), with the other conditions fixed, the highest etch rate was obtained. As the RF power and the dc-bias voltage were increased, the etch rate of the TaN thin film was increased. X-ray photoelectron spectroscopy (XPS) was used to investigate the chemical states of the surface of the TaN thin film.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.12
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• pp.1051-1056
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• 2008

In this study, the investigations of the TiN etching characteristics were carried out with addition of $Cl_2$ gas in an inductively coupled $BCl_3$-base plasma system. Dry etching of the TiN was studied by varying the etching parameters including $Cl_2$ gas addition ratio, RF power, DC-bias voltage and pressure. The etch rate of TiN thin film was maximum when the $Cl_2$ gas addition flow was 2 sccm with fixed other conditions. As the RF power DC-bias voltage were increased, the etch rate of TiN thin film showed increasing tendency. $BCl_3/Cl_2$/Ar plasmas were characterized by optical emission spectroscopy (OES) analysis. The chemical reaction on the surface of the etched TiN films was investigated with X-ray photoelectron spectroscopy (XPS).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.382-382
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• 2010

The etch characteristics of the $HfAlO_3$ thin films and selectivity of $HfAlO_3$ to $SiO_2$ in $Cl_2/BCl_3$/Ar plasma were investigated in this work. The maximum etch rate was 108.7 nm/min and selectivity of $HfAlO_3$ to $SiO_2$ was 1.11 at $Cl_2$(3sccm)/$BCl_3$(4sccm)/Ar(16sccm), RF power of 500 W, DC-bias voltage of - 100 V, process pressure of 1 Pa and substrate temperature of $40^{\circ}C$. As increasing RF power and DC-bias voltage, etch rates of the $HfAlO_3$ thin films increased. Whereas as decreasing of the process pressure, those of the $HfAlO_3$ thin films were increased. The chemical reaction on the surface of the etched the $HfAlO_3$ thin films was investigated with X-ray photoelectron spectroscopy (XPS).

• Applied Science and Convergence Technology
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• v.23 no.6
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• pp.357-365
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• 2014

A non-invasive method for ion energy distribution measurement at a RF biased surface is proposed for monitoring the property of ion bombardments in capacitively coupled plasma sources. To obtain the ion energy distribution, the measured electrode voltage is analyzed based on the circuit model which is developed with the linearized sheath capacitance on the assumption that the RF driven sheath behaves like a simple diode for a bias power whose frequency is much lower than the ion plasma frequency. The method is verified by comparing the ion energy distribution function obtained from the proposed model with the experimental result taken from the ion energy analyzer in a dual cathode capacitively coupled plasma source driven by a 100 MHz source power and a 400 kHz bias power.

• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.867-869
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• 1999

In this study, $SrBi_{2}Ta_{2}O_{9}$(SBT) thin films were etched as a function of $SF_6$/Ar gas mixing ratio in magnetically enhanced inductively coupled plasma(MEICP) system fer a fixed rf power, dc-bias voltage, and chamber pressure. The etch rate of SBT thin film was $1500{\AA}/min$ and the selectivities of photoresist (PR) and $SiO_2$ to SBT thin film were 0.48 and 0.62, respectively when the samples were etched at a rf power of 600W, a dc-bias voltage of -150V, a chamber pressure of 10 mTorr and a gas mixing ratio of $SF_6/(SF_6+A)$=0.1. In order to examine the chemical reactions on the etched surface, X-ray photoelectron spectroscopy(XPS) and secondary ion mass spectrometry(SIMS) were done.

• Transactions on Electrical and Electronic Materials
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• v.11 no.4
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• pp.166-169
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• 2010

In this study, we changed the etch parameters (gas mixing ratio, radio frequency [RF] power, direct current [DC]-bias voltage, and process pressure) and then monitored the effect on the $HfAlO_3$ thin film etch rate and the selectivity with $SiO_2$. A maximum etch rate of 108.7 nm/min was obtained in $Cl_2$ (3 sccm)/$BCl_3$ (4 sccm)/Ar (16 sccm) plasma. The etch selectivity of $HfAlO_3$ to $SiO_2$ reached 1.11. As the RF power and the DC-bias voltage increased, the etch rate of the $HfAlO_3$ thin film increased. As the process pressure increased, the etch rate of the $HfAlO_3$ thin films increased. The chemical state of the etched surfaces was investigated with X-ray photoelectron spectroscopy. According to the results, the etching of $HfAlO_3$ thin film follows the ion-assisted chemical etching.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.4
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• pp.305-310
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• 2008

Deep trench etching of silicon was investigated as a function of RF source power, DC bias voltage, $C_4F_8$ gas flow rate, and $O_2$ gas addition. On increasing the RF source power from 300 W to 700 W, the etch rate was increased from $3.52{\mu}m/min$ to $7.07{\mu}m/min$. The addition of $O_2$ gas improved the etch rate and the selectivity. The highest etch rate is achieved at the $O_2$ gas addition of 12 %, The selectivity to PR was 65.75 with $O_2$ gas addition of 24 %. At DC bias voltage of -40 V and $C_4F_8$ gas flow rate of 30 seem, We were able to achieve etch rate as high as $5.25{\mu}m/min$ with good etch profile.