• The Journal of the Korea Contents Association
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• v.8 no.11
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• pp.235-241
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• 2008

If the target volume cannot be included with one field at head and neck cancer, we commonly used two or more field. It is very important to irradiate uniform dose at junction area of the fields. However, according to body shape of patient or general condition of patient, skin junction area can be matched incorrect, So overdose area or underdose area can be appeared in the junction area. This study researched therapy technique which can give uniform dose at skin junction owing to applying the edge block of lateral field at head and neck cancer. We measured the changed distance and rotational angle between central line of anterior supraclavicle lymph node and low margin of right lateral field on simulation process using the shielding block of variable rotation. As a result, the changed distance between central line of anterior supraclavicle lymph node and low margin of right lateral field was below 2mm to ${\pm}$10cm distance at central line of Y axis, changed angle was average 1.28 degree. But by using it the shielding block of variable rotation, the incorrect match at junction can be minimized. We think that this technique is very efficient one to apply this technique at head and neck cancered by the movement of organs can be not included, Therefore we have to pay attention on the process to imput MLC layer

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.6
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• pp.300-304
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• 2004

We have proposed the junction termination design employing shallow trench filled with silicon dioxide and field limiting ring (FLR). We have designed trenches between P+ FLRs to decrease the junction termination radius without sacrificing the breakdown voltage characteristics. We have successfully fabricated and measured improved breakdown voltage characteristics of the Proposed device for 1200 V-class applications. The junction termination radius of the proposed device has decreased by 15%-21% compared with that of the conventional FLR at the identical breakdown voltage. The junction termination area of the proposed device has decreased by 37.5% compared with that of the conventional FLR. The breakdown voltage of the proposed device employing 7 trenches was 1156 V, which was 80% of the ideal parallel-plane .junction breakdown voltage.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.6
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• pp.257-260
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• 2003

We have proposed the junction termination structure of IGBT (Insulated Gate Bipolar Transistor) by employing trench and FLR (Field Limiting Ring), which decrease the junction termination area at the same breakdown voltage. Our proposed junction termination structure, trench FLR is verified by numerical simulator MEDICI. In 600V rated device, the junction termination area is decreased 20% compared with that of the conventional FLR structure. The breakdown voltage of trench FLR with 4 trenches is 768 V, 99 % of ideal parallel-plane junction(1-D) $BV_ceo$.

• Journal of IKEEE
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• v.11 no.4
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• pp.235-238
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• 2007

The planar edge termination techniques of field-ring and deep junction field-ring were investigated and optimized using a two-dimensional device simulator TMA MEDICI. By trenching the field ring site which would be implanted, a better blocking capability can be obtained. The results show that the p-n junction with deep junction field-ring can accomplish near 30% increase of breakdown voltage in comparison with the conventional field-rings. The deep junctionfield-rings are easy to design and fabricate and consume same area but they are relatively sensitive to surface charge. Extensive device simulations as well as qualitative analyses confirm these conclusions.

• ETRI Journal
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• v.37 no.5
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• pp.951-960
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• 2015

For a conventional power metal-oxide-semiconductor field-effect transistor (MOSFET), there is a trade-off between specific on-state resistance and breakdown voltage. To overcome this trade-off, a super-junction trench MOSFET (TMOSFET) structure is suggested; within this structure, the ability to sense the temperature distribution of the TMOSFET is very important since heat is generated in the junction area, thus affecting its reliability. Generally, there are two types of temperature-sensing structures-diode and resistive. In this paper, a diode-type temperature-sensing structure for a TMOSFET is designed for a brushless direct current motor with on-resistance of $96m{\Omega}{\cdot}mm^2$. The temperature distribution for an ultra-low on-resistance power MOSFET has been analyzed for various bonding schemes. The multi-bonding and stripe bonding cases show a maximum temperature that is lower than that for the single-bonding case. It is shown that the metal resistance at the source area is non-negligible and should therefore be considered depending on the application for current driving capability.

• Journal of Radiation Protection and Research
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• v.36 no.3
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• pp.168-173
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• 2011

This study investigated characteristics of dose distribution at junction field of X-ray and electron beams according to the method for fabricating the insert block on the electron cone. Insert block were fabricated to the divergency cutout block and the straight cutout block. For the 6 MV X-ray and 10 MeV nominal energy of electron beam, we was adjacent to the light field of X-ray and electron beam at a surface of matrix chamber and measured to beam profile of abutted field in the 0, 1, 2, 3 cm measurement depth. As a result, characteristics of dose distribution at junction field, straight block was existent that over dose area exceed the give dose more than 5% and under dose area with a rapid change in dose distribution. However, divergency block had remarkably decreased the over dose area caused by the lateral scattering effects of decrease, and being existed uniformity dose distribution in the junction field. Therefore, divergency block were the benefits of radiation dose delivery, in order to applied the clinical, measurement of electron beams according to the fabrication method of the block should be considered carefully.

• Transactions on Electrical and Electronic Materials
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• v.11 no.6
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• pp.271-274
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• 2010

We examined the tunneling current behaviors of magnetic tunneling junction (MTJ) cells utilizing conductive atomic force microscopy (AFM) interfaced with an external magnetic field generator. By introducing current through coils, a magnetic field was generated and then controlled by a current feedback circuit. This enabled the characterization of the tunneling current under various magnetic fields. The current-voltage (I-V) property was measured using a contact mode AFM with a metal coated conducting cantilever at a specific magnetic field intensity. The obtained magnetoresistance (MR) ratios of the MTJ cells were about 21% with no variation seen from the different sized MTJ cells; the value of resistance $\times$ area (RA) were 8.5 K-12.5 K $({\Omega}{\mu}m^2)$. Since scanning probe microscopy (SPM) performs an I-V behavior analysis of ultra small size without an extra electrode, we believe that this novel characterization method utilizing an SPM will give a great benefit in characterizing MTJ cells. This novel method gives us the possibility to measure the electrical properties of ultra small MTJ cells, namely below $0.1\;{\mu}m\;{\times}\;0.1\;{\mu}m$.

• ETRI Journal
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• v.19 no.4
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• pp.402-413
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• 1997

A CMOS device which has an extended heavily-doped amorphous silicon source/drain layer on the field oxide and an amorphous silicon local interconnection (ASLI) layer in the self-aligned source/drain region has been studied. The ASLI layer has some important roles of the local interconnections from the extended source/drain to the bulk source/drain and the path of the dopant diffusion sources to the bulk. The junction depth and the area of the source/drain can be controlled easily by the ASLI layer thickness. The device in this paper not only has very small area of source/drain junctions, but has very shallow junction depths than those of the conventional CMOS device. An operating speed, however, is enhanced significantly compared with the conventional ones, because the junction capacitance of the source/drain is reduced remarkably due to the very small area of source/drain junctions. For a 71-stage unloaded CMOS ring oscillator, 128 ps/gate has been obtained at power supply voltage of 3.3V. Utilizing this proposed structure, a buried channel PMOS device for the deep submicron regime, known to be difficult to implement, can be fabricated easily.

• Journal of the Korean Magnetics Society
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• v.12 no.2
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• pp.68-72
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• 2002

In this research, the effects of capacitance to the access time were studied at the junction area of tunneling magnetoresistance when these were used as memory devices. These results were obtained by applying electric signal input and magnetic field was not used. We applied bipolar square waves of 1MHz to the MTJ samples to obtain the results and time constant ($\tau$) calculated by observing wave responses utilizing an oscilloscope. And time constant was compared with junction area. Each part of MTJ sample, such as electrical pad, lead and contact area, was modeled as an electrical equivalent circuit based on experimental results. For the 200㎛$\times$200㎛ cell, junction capacitance was 90 pF. Also, measurement and simulation results were compared, which showed those similarity.

• Journal of the Korean Institute of Telematics and Electronics
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• v.21 no.1
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• pp.62-70
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• 1984

N+NPP+ HLEBSF (high low emitter back surface field) solar cells which have N+N high low junction in the emitter as well as N+PP+ BSF cells were designed and fabricated by using <111> oriented P type Si wafers with the resistivity of 10$\Omega$/$\textrm{cm}^2$ and the thickness of 13-15 mil. Physical parameters (impurity concentration, thickness) at each region of N+PP+ and N+NPP+ cell were made equally through same masks and simultaneous process except N region of HLEBSF cell to investigate the high low emitter junction effect for efficiency improvement. Under the light intensity of 100 mW/$\textrm{cm}^2$, total area (active area) conversion efficiency were typically 10.94% (12.16%) for N+PP+ BSF cells and 12.07% (13.41%) for N+N PP+ cells. Efficiency improvement of N+NPP+ cell which has high low emitter Junction structure is resulted from the suppression of emitter recombination current and the increasement of open circuit voltage (Voc) and short circuit current (Ish) by removing heavy doping effects occurring in N+ emitter region.