• Journal of Radiation Protection and Research
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• v.18 no.1
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• pp.25-35
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• 1993

To develop a technique of theoretical alpha track density calculation for comparison with measured track density, an electrostatic ion spectrometer was specially designed and fabricated. The mobility spectrum of first radon daughter(Po-218) in the range of $0.07{\sim}5.0cm^2/V\;s$ from the radon chamber was measured using-the electrostatic ion spectrometer. Measurement was taken in a radon chamber operated using dry particle free air passed through silica gel, activated charcoal and molecular sieve filters. The mobility of a new-born Po-218 ion measured by the electrostatic ion spectrometer was determined to be $1.92cm^2/V\;s$. A comparison of the theoretical and measured alpha track densities was completed and uncertainties concerning the shape of the spectrum were analyzed. It was found that the discrepancies in track densities are primarily Que to the neglect of wall loss of ions in the theoretical track density calculation.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.4
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• pp.204-208
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• 2006

In this study, we investigated the ion energy distributions in a chlorine based inductively coupled plasma by quadrupole mass spectrometer with an electrostatic ion energy analyzer. Ion energy distributions are presented for various plasma parameters such as $BCl_3/Ar$ gas mixing ratio, RF power, and process pressure. As the $BCl_3/Ar$ gas mixing ratio and process pressure decreases, and RF power increases, the saddle-shaped structures is enhanced. The reason is that there are ionized energy difference between $BCl_3$ and Ar, change of plasma potential, alteration of mean free path. and variety of ion collision in the sheath.

• Journal of Sensor Science and Technology
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• v.7 no.3
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• pp.163-170
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• 1998

An ion energy spectrometer which has the $45^{\circ}$ parallel electrostatic deflection plate was designed and constructed for measuring ion temperature in high temperature plasma. The energy calibration and the energy resolution were studied in detail for a hydrogen ion at the $0.24{\sim}1.92\;keV$ energy using electrostatic accelerator with a duoplasmatron ion source. The voltage of the deflection plate was linearly increased for the decreased ion detector position at the constant ion energy and decreased for the increased ion energy at the fixed ion detector position. The inclination of the deflection plate voltage to the ion energy was between 0.92 and 1.61, and linearly decreased for the increased the ion detector position. The measured energy resolution, which is $4.2%\;{\sim}\;11.6%$ in this experiment region, was improved for the increased ion dector position and ion energy. The relative efficiency was increased for the decreased the ion detector position. The ion energy spectrum of the DC plasma in the multi-purpose plasma generator was measured using this equipment. The ion temperature was 203-205 eV at the discharge voltage 320 V, discharge current 1.7 A.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.2
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• pp.349-354
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• 2007

In this work, we investigated etching characteristics of $HfO_2$ thin film and Si using inductive coupled plasma(ICP) system. The ion energy distribution functions in an ICP system was analyzed by quadrupole mass spectrometer(QMS) with an electrostatic ion energy analyzer. The maximum etch rate of $HfO_2$ thin film is 85.5 nm/min at a $BCl_3/(BCl_3+Ar)$ of 20 % and decreased with further addition of $BCl_3$ gas. From the QMS measurements, the most dominant positive ion energy distributions(IEDS) showed a maximum at 20 % of $BCl_3$. These tendency was very similar to the etch characteristics. This result agreed with the universal energy dependency of ion enhanced chemical etching yields. And the maximum selectivity of $HfO_2$ over Si is 3.05 at a $O_2$ addition of 2 sccm into the $BCl_3/(BCl_3+Ar)$ of 20 % plasma.

• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.117-118
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• 2006

In this work, we investigated etching characteristics of $HfO_2$ thin film and Si using inductive coupled plasma (ICP) system. The ion energy distribution functions in an inductively coupled plasma was analyzed by quadrupole mass spectrometer with an electrostatic ion energy analyzer. The maximum etch rate of $HfO_2$ is 85.5 nm/min at a $BCl_3/(BCl_3+Ar)$ of 20% and decreased with further addition of $BCl_3$ gas. From the QMS measurements, the most dominant positive ion energy distributions (IEDs) showed a maximum at 20 % of $BCl_3$. These tendency was very similar to the etch characteristics. This result agreed with the universal energy dependency of ion enhanced chemical etching yields. And the maximum selectivity of $HfO_2$ over Si is 3.05 at a O2 addition of 2 sccm into the $BCl_3/(BCl_3+ Ar)$ of 20% plasma.

• Journal of Radiation Protection and Research
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• v.20 no.2
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• pp.79-83
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• 1995

A number of investigators have reported formation of radiolytic ultrafine particles produced by the interaction of ionizing radiation with atmospheric trace gases. Previous studies have suggested that a very high localized concentration of the hydroxyl radical produced by the radiolysis of water can react with atmospheric trace gases such as $SO_2$ and produce lower vapor pressure compounds that can subsequently nucleate. To determine the trace gas and water vapor concentration dependence of the active, positively charged, first decayt product of radon (Po-218), a well-controlled radon chamber was used in this research. The mobility spectrum of the decay products in the range of $0.07-5.0cm^2/V\;sec$ from the radon chamber was measured using alpha track detector installed inside a specially-designed electrostatic spectrometer. Measurements were taken for different concentrations (0.5ppm to 5ppm) of $SO_2$ in Purified, Compressed air. A kinetics Study following the clustering of $SO_2$ around the $PoO_x^+$ ion in an excess of $SO_2$ for interpretation of the reaction processes was performed.