• JSTS:Journal of Semiconductor Technology and Science
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• v.8 no.1
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• pp.11-20
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• 2008

The structure of 2-bit/cell flash memory device was characterized for sub-50 nm non-volatile memory (NVM) technology. The memory cell has spacer-type storage nodes on both sidewalls in a recessed channel region, and is erased (or programmed) by using band-to-band tunneling hot-hole injection (or channel hot-electron injection). It was shown that counter channel doping near the bottom of the recessed channel is very important and can improve the $V_{th}$ margin for 2-bit/cell operation by ${\sim}2.5$ times. By controlling doping profiles of the channel doping and the counter channel doping in the recessed channel region, we could obtain the $V_{th}$ margin more than ${\sim}1.5V$. For a bit-programmed cell, reasonable bit-erasing characteristics were shown with the bias and stress pulse time condition for 2-bit/cell operation. The length effect of the spacer-type storage node is also characterized. Device which has the charge storage length of 40 nm shown better ${\Delta}V_{th}$ and $V_{th}$ margin for 2-bit/cell than those of the device with the length of 84 nm at a fixed recess depth of 100 nm. It was shown that peak of trapped charge density was observed near ${\sim}10nm$ below the source/drain junction.

• Journal of Sensor Science and Technology
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• v.29 no.4
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• pp.275-278
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• 2020

In this study, we evaluated the temperature-dependent characteristics of homojunction InGaAs vertical Fin-shaped Tunnel Field-Effect Transistors (Fin TFETs), which were fabricated using a novel nano-fin patterning technique in which the Au electroplating and the high-temperature InGaAs dry-etching processes were combined. The fabricated homojunction InGaAs vertical Fin TFETs, with a fin width and gate length of 60 nm and 100 nm, respectively, exhibited excellent device characteristics, such as a minimum subthreshold swing of 80 mV/decade for drain voltage (V_DS) = 0.3 V at 300 K. We also analyzed the temperature-dependent characteristics of the fabricated TFETs and confirmed that the on-state characteristics were insensitive to temperature variations. From 77 K to 300 K, the subthreshold swing at gate voltage (V_GS) = threshold voltage (V_T), and it was constant at 115 mV/decade, thereby indicating that the conduction mechanism through band-to-band tunneling influenced the on-state characteristics of the devices.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.9
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• pp.687-692
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• 1998

Silicon doped $Al_{0.32}Ga_{0.68}As$ were growth by molecular beam epitaxy. Electroreflectance(ER) spectra of the $E_1$ transition of Schottky barrier Au/n-$Al_{0.32}Ga_{0.68}As$ have been measured at various modulation voltage($V_{ac}$) and dc bias voltage($V_{bias}$). from the $E_1$peak, band gap energy of the $Al_{0.32}Ga_{0.68}As$ is 1.883 eV which corresponds to an Al composition of 32%. As modulation voltage($V_{bias}$) is changed, a line shape at the $E_1$transition does not change, but its amplitude varies linearly. The amplitude of $E_1$signal decrease with increasing the forward dc bias voltage($V_{bias}$), but the line shape does not change. It suggests that the low field theory rather than Franz-Keldysh oscillation is Required to interpret spectra. Also, spectra at the $E_1$transition were broadened with increasing the reverse dc bias voltage($V_{bias}$) which suggests the presence of Field-induced broadening.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.37-37
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• 2009

박막태양전지는 p-i-n substrate형과 n-i-p substrate형 두가지구조로 제조된다. 각 layer에서 activation energy와 band gap energy를 ASA simulator를 통해 조절해보았다. Simulation결과 p-i-n substrate형에서 p-layer와 n-i-p substrate형 n-layer에서 동일하게 activation energy 0.2eV, band gap energy 1.80eV에 최고효율 나왔고 각각 10.07%, 10.17%의 최고효율을 구할 수 있었다. 최적화 과정을 통하여 같은 조건에서 p-i-n substrate형 보다 n-i-p substrate형이 보다 높은 효율을 낸다는 것을 알 수 있었으며 본 연구를 통해 각 구조의 차이를 알 수 있었고 이는 높은 효율의 박막태양전지 설계에 도움이 될 것 이다.

• Proceedings of the IEEK Conference
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• 2004.06a
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• pp.201-204
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• 2004

In this paper, a down-converter that can work for L-band RF front-end of DMB receiver is designed. Since DRK-02, a reference for our work, had been designed for a stationary receiver, not for mobile one, the supply voltage is set relatively high of 8.5V. We improve it with 3.3V and save design space and cost by employing only one Mixer and IF_Amp comparing to the reference one in which two Mixers and two IF_Amps are used.

• Korean Journal of Materials Research
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• v.17 no.1
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• pp.1-5
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• 2007

GaN thin fan were grown by spin coated colloidal GaOOH precursor. Polycrystalline GaNs with crystalline size of $10{\sim}100nm$ were grown on $SiO_2$ substrate. The shape of crystallite above $900^{\circ}C$ had the hexagonal plate and column type. X-ray diffraction patterns for them correspond to those of the hexagonal wurtzite GaN. With increasing droplets. i.e, thickness of deposited layers, XRD intensity increased. PL (photoluminescence) spectrum consisted with an weak near band-edge emission at 3.45 eV and a broad donor-acceptor emission band at 3.32 eV. From the low temperature PL measurement on GaN grown at $800^{\circ}C$ that the shallow donor-acceptor recombination induced emission was more intense than the near band-edge excitonic emission.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.813-815
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• 1992

Accurate Capacitance-Voltage characteristics of Metal-Insulator-Semiconductor (MIS) devices in narrow band-gap semiconductors are presented. The unique band structure of narrow band-gap semiconductors is taken into account such as non-parabolicity and degeneracy. Compensated and partially ionized impurities either in the bulk or the space charge region are also considered. HgCdTe is a defect semiconductor, so this approach is very important for characterization and analysis of MIS devices.

• Journal of environmental and Sanitary engineering
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• v.15 no.2
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• pp.102-111
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• 2000

As IR-sensor for detecting pollution material, the iron silicide has a fit band gap, high physicochemical stability at high temperature and good acid resistance. The growing film was formed with the Fe-Si bond and the organic compound because plasma resolved the injected precursors into various active species. In the Raman scattering spectrum, the Fe-Si vibration mode showed at 250 {TEX}$cm^{-1}${/TEX}. The FT-IR peak indicated that the various organic compounds were deposited on the films. The iron silicide was epitaxially grown to β-phase by the high energy of plasma. The lattice structure of films had [220]/[202] and [115]. The thickness of the films increased with the flow rate of silane. But rf-power increased with decreasing the thickness. The optical gap energy and the band gap were shown about 3.8 eV and 1.182∼1.194 eV. The band gap linearly increased and the formula was below: {TEX}$E_g^{dir}${/TEX}= 8.611×{TEX}$10^{-3}N_{D}${/TEX}＋1.1775

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.977-979
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• 2006

Organic light-emitting diodes (OLEDs) based on the double wide band gap emissive layers in the range of 380 nm to 440 nm are reported. An efficient electroluminescence with a maximum at 400nm was observed at room temperature under a forward bias about 10V. With the wide band gap organic materials for near-ultraviolet emission, the low operating voltage (5V) and high current efficiency (3 cd/A) have been obtained at $2mA/cm^2$

• Journal of the Korean Ceramic Society
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• v.47 no.4
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• pp.353-356
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• 2010

Zinc oxide (ZnO) thin films were deposited using atomic layer deposition. The electrical and optical properties were characterized using Hall measurements, spectroscopic ellipsometry and UV-visible spectrophotometry. The electronic concentration and the mobility were found to be critically dependent on the deposition temperature, exhibiting increased resistivity and reduced electronic mobility at low temperature. The corresponding optical properties were measured as a function of photon energy ranging from 1.5 to 5.0 eV. The simulated extinction coefficients allowed the determination of optical band gaps, i.e., ranging from 3.36 to 3.41 eV. The electronic carrier concentration appears to be related to the reduction in the corresponding band gap in ZnO thin films.