• Journal of IKEEE
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• v.27 no.4
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• pp.399-404
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• 2023

In this paper, we analyzed the current path in the O/N/O (Oxide/Nitride/Oxide) structure of 3D NAND Flash memory and in the O/N/F (Oxide/Nitride/Ferroelectric) structure where the blocking oxide is replaced by a ferroelectric. In the O/N/O structure, when V_read is applied, a current path is formed on the backside of the channel due to the E-fields of neighboring cells. In contrast, the O/N/F structure exhibits a current path formed on the front side due to the polarization of the ferroelectric material, causing electrons to move toward the channel front. Additionally, we performed an examination of device characteristics considering channel thickness and channel length. The analysis results showed that the front electron current density in the O/N/F structure increased by 2.8 times compared to the O/N/O structure, and the front electron current density ratio of the O/N/F structure was 17.7% higher. Therefore, the front current path is formed more effectively in the O/N/F structure than in the O/N/O structure.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.9
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• pp.751-755
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• 2009

We proposed circular AlGaN/GaN schottky barrier diode, which has no mesa structure near the current path. Proposed device showed low leakage current of 10 nA/mm at -100 V while that of the rectangular device was 34 nA/mm at the same condition. Proposed circular AIGaN/GaN SBD showed high forward current of 88.61 mA at 3,5 V while that of the conventional device was 14.1 mA at the same condition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.04b
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• pp.89-90
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• 2009

Three kind of surface-leakage-test-patterns were fabricated and measured in order to investigate the surface leakage current of AlGaN/GaN heterostructures through etched GaN buffer surface and mesa wall. The pattern which contain the mesa wall has the largest surface leakage current among them. The leakage current due to the mesa wall is predominant source of the leakage current of AlGaN/GaN devices.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.6
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• pp.617-621
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• 2013

This study examined the effect of electron-beam (E-beam) irradiation on the electrical properties of n-GaN, AlGaN and AlGN/GaN structures on sapphire substrates. E-beam irradiation resulted in a significant decrease in the gate leakage current of the n-GaN, AlGaN and HEMT structure from $4.0{\times}10^{-4}A$, $6.5{\times}10^{-5}A$, $2.7{\times}10^{-8}A$ to $7.7{\times}10^{-5}A$, $7.7{\times}10^{-6}A$, $4.7{\times}10^{-9}A$, respectively, at a drain voltage of -10V. Furthermore, we also investigated the effect of E-beam irradiation on the AlGaN surface in AlGaN/GaN heterostructure high electron mobility transistors(HEMTs). The results showed that the maximum drain current density of the AlGaN/GaN HEMTs with E-beam irradiation was greatly improved, when compared to that of the AlGaN/GaN HEMTs without E-beam irradiation. These results strongly suggest that E-beam irradiation is a promising method to reduce leakage current of AlGaN/GaN HEMTs on sapphire through the neutralization the trap.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.4
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• pp.21-27
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• 2009

In this work, Er-silicided SB-SOI nMOSFET and Pt-silicided SB-SOI pMOSFET have been fabricated to investigate the current-voltage characteristics of Schottky barrier SOI nMOS and pMOS at elevated temperature. The dominant current transport mechanism of SB nMOS and pMOS is discussed using the measurement results of the temperature dependence of drain current with gate voltages. It is observed that the drain current increases with the increase of operating temperature at low gate voltage due to the increase of thermal emission and tunneling current. But the drain current is decreased at high gate voltage due to the decrease of the drift current. It is observed that the ON/Off current ratio is decreased due to the increased tunneling current from the drain to channel region although the ON current is increased at elevated temperature. The threshold voltage variation with temperature is smaller and the subthreshold swing is larger in SB-SOI nMOS and pMOS than in SOI devices or in bulk MOSFETs.

• Journal of Biomedical Engineering Research
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• v.18 no.3
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• pp.307-313
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• 1997

he photoconductive gain mechanism in amorphus silicon devices was investigated in connection with applications to radiation detection. Various device types such as p-i-n, n-i-n and i-i-p-i-n structures were fabricated and tested. Photoconductive gain was measured in two time scales : one for short pulses of visible light(<$1{\mu}sec$) which simulate the transit of energetic charged particles or ${\gamma}$-rays, and the other for rather long pulses of light(1msec) which simulate x-ray exposure in medical imaging, We used two definitions of phtoconductive gain : current gain and charge gain which is an integration of the current gain. We obtained typical charge gains of 3~9 for short pulses and a few hundreds for long pulses at a dark current density level of 10mA/$cm^2$. Various gain results are discussed in terms of the device structure, applied bias and dark current density.

• Proceedings of the Optical Society of Korea Conference
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• 2008.02a
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• pp.231-232
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• 2008

The effect of n-electrode patterns on the current distribution in active region is investigated in GaN-based blue vertical light emitting diodes (VLEDs). A 3-dimension circuit model is adopted to analyze the current flow patterns in VLEDs. We had fabricated VLEDs having different n-electrode patterns, measured their current-voltage characteristics, and compared to the numerical simulation. It turns out that the current spreading in VLEDs is strongly dependent on the n-electrode pattern. Some design guidelines for n-electrode patterns to produce uniform current injection are presented.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.8
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• pp.116-121
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• 2005

To realize the tap coefficient of a finite impulse response(FIR) filter or the twiddle factor of a fast Fourier transform(FFT) using a current-mode analog circuit, a high accurate current-attenuator circuit is needed This paper introduces an accuracy enhancement technique in the current-mode signal processing. First of all, the DC of set-current error in a conventional current-attenuator using a gate-ratioed orient mirror circuit is analyzed and then, the current-attenuator circuit with a negligibly small DC offset-current error is introduced. The circuit consists of N-output current mirrors connected in parallel with me another. The output current of the circuit is attenuated to 1/N of the input current. On the basis of the Kirchhoff current law, the current scale ratio is determined simply by the number of the current mirrors in the N-current mirrors connected in parallel. In the proposed current-attenuator circuit the scale accuracy is limited by the ac gain error of the current mirror. Considering that a current mirror has a negligibly small ac gain error, the attainable maximum scale accuracy is theoretically -80[dB] to the input current.

• Journal of Sensor Science and Technology
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• v.21 no.1
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• pp.1-6
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• 2012

Using a current-mode multiple reset, a current-to-voltage(I-V) converter with a wide dynamic range was produced. The converter consists of a trans-impedance amplifier(TIA), an analog-to-digital converter(ADC), and an N-bit counter. The digital output of the I-V converter is composed of higher N bits and lower bits, obtained from the N-bit counter and the ADC, respectively. For an input current that has departed from the linear region of the TIA, the counter increases its digital output, this determines a reset current which is subtracted from the input current of the I-V converter. This current-mode reset is repeated until the input current of the TIA lies in the linear region. This I-V converter is realized using 0.35 ${\mu}m$ LSI technology. It is shown that the proposed I-V converter can increase the maximum input current by a factor of $2^N$ and widen the dynamic range by $6^N$. Additionally, the I-V converter is successfully applied to a photometric sensor.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.12S
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• pp.1268-1272
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• 2003

In order to enhance current Injection efficiency of Y-groove inner strife(VIS) quantum wire lasers, three different current configurations, n-blocking on p-substrate(VIPS), p-n-p-n blocking on n-substrate(VI(PN)nS), p-blocking on n-substrate(VINS) have been designed and fabricated. Among them VIPS laser showed the most stable characteristics of lasing up to 5 mW/facet, a threshold current of 39.9 mA at 818 nm, and an external differential quantum efficiency of 24 %/facet. The current tuning rate was almost linear 0.031 nm/mA, and the temperature tuning rate was measured to be 0.14 nm/$^{\circ}C$.