• Journal of Sensor Science and Technology
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• v.31 no.1
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• pp.31-35
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• 2022

The efficacy improvement of the light emitting diode (LED) was studied for the realization of small-size, low power consumption, and highly sensitive bio-sensor instrument. The performance of the LED with Mg delta-doping at the interface of AlGaN/GaN super-lattice in p type cladding layer was simulated. The device with Mg delta-doping showed improved current, radiative recombination rate, electroluminescence, and light output power compared to the conventional LED structure. Under the bias condition of 5 V, the improved device exhibited 20.8% increase in the light output power. This is attributed to the increment of hole concentration from stable ionization of Mg in p type cladding layer. This result is expected to be used for the miniaturization, power saving, and sensitivity improvement of the bio-sensor system.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.37 no.3
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• pp.332-336
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• 2024

High-energy bandgap material silicon carbide (SiC) is gaining attention as a next-generation power semiconductor material, and in particular, SiC-based MOSFETs are developed as representative power semiconductors to increase the breakdown voltage (BV) of conventional planar structures. However, as the size of SJ (Super Junction) MOSFET devices decreases and the depth of pillars increases, it becomes challenging to uniformly form the doping concentration of pillars. Therefore, a structure with different doping concentrations segmented within the pillar is being researched. Using Silvaco TCAD simulation, a SJ VVD (vertical variation doping profile) MOSFET with three different doping concentrations in the pillar was studied. Simulations were conducted for the width of the pillar and the doping concentration of N-epi, revealing that as the width of the pillar increases, the depletion region widens, leading to an increase in on-specific resistance (R_on,sp) and breakdown voltage (BV). Additionally, as the doping concentration of N-epi increases, the number of carriers increases, and the depletion region narrows, resulting in a decrease in R_on,sp and BV. The optimized SJ VVD MOSFET exhibits a very high figure of merit (BFOM) of 13,400 KW/cm², indicating excellent performance characteristics and suggesting its potential as a next-generation highperformance power device suitable for practical applications.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.288-288
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• 2012

In this study, we investigated that the resistance switching characteristics of W-doped NbOx films with increasing W doping concentration. The W-doped NbOx based ReRAM devices with a TiN/W-doped NbOx/Pt/Ti/SiO2 were fabricated on Si substrates. The 50 nm thick W-doped NbOx films were deposited by reactive dc magnetron co-sputtering at $400^{\circ}C$ and oxygen partial pressure of 35%. Micro-structure of W-doped NbOx films and atomic concentration were investigated by XRD, TEM and XPS, respectively. The W-doped NbOx films showed set/reset resistance switching behavior at various W doping concentrations. The process voltage of set/reset is decreased and whereas the initial current level is increased with increasing W doping concentration in NbOx films. The change of resistance switching behavior depending on doping concentration was discussed in terms of concentration of metallic tungsten of oxygen of W-doped NbOx.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.344-345
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• 2012

The Gate-Induced-Drain-Leakage (GIDL) current with channel doping and width dependence are characterized. The GIDL currents are found to increase in MOSFETs with higher channel doping levels and the observed GIDL current is generated by the band-to-band-tunneling (BTBT) of electron through the reverse-biased channel-to-drain p-n junction. A BTBT model is used to fit the measured GIDL currents under different channel-doping levels. Good agreement is obtained between the modeled results and experimental data. The increase of the GIDL current at narrower widths in mainly caused by the stronger gate field at the edge of the shallow trench isolation (STI). As channel width decreases, a larger portion of the GIDL current is generated at the channel-isolation edge. Therefore, the stronger gate field at the channel-isolation edge causes the total unit-width GIDL current to increases for narrow-width devices.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2005.05a
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• pp.173-179
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• 2005

본 연구에서는 Nickel-Metal Induced Lateral crystallization(Ni-MILC)에 depart에 따른 영향을 관찰함에 있어 Nickel에 Palladium Metal을 인접시켜(Pd assisted Ni-MILC) 그 결정화 속도를 향상시키는 방법을 제안하였다. a-Si에 Phosphorous가 doping 되어 있는 경우 Ni-MILC의 성장은 intrinsic에 비해 2.5배 감소되는 반면, Boron을 doping한 경우 Ni-MILC의 성장은 intrinsic의 경우보다 5배 이상의 성장을 보이게 되는데, well type의 Pd을 인접시킨 경우 Pd에 의해 유도된 tensile stress가 각 doping에 따른 성장 속도를 더욱 증대시키는 것을 확인할 수 있었으며, 이와 같은 현상을 MILC mechanism으로 설명하였다. 이는 Ni-MILC를 이용하여 다결정 실리콘 TFT 제작 시 결정화 속도로 인하여 문제가 되었던 N-type에서의 적용이 가능함과 동시에 contact MILC 등의 방법에도 이용가능성을 의미한다.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.1
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• pp.9-14
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• 2004

In this paper, temperature dependence of effective ionization coefficient in Si is formulated as a single polynomial function of temperature, which allows analytical expressions for breakdown voltage of Si $p^+n$ junction as a function of temperature. The analytical breakdown voltages agree well with the simulation as well as the experimental ones reported within $3\%$ in error for the doping concentrations in the range of $10^{14}cm^{-3}{\~} 10^{17}cm^{-3}$ at 100K, 300K and 500K.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1650-1653
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• 2007

We demonstrate fluorescent green organic lightemitting diodes employing a rhenium oxide ($ReO_3$)-doped N,N-diphenyl-N,N'-bis(1,1'-biphenyl)-4,4'-diamine (NPB) hole transporting layer (HTL). The devices exhibit significantly reduced driving voltages as well as prolonged lifetime. Details of $ReO_3$ doping effects are described in terms of charge transfer complex and stabilization of HTL morphology.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.3
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• pp.235-238
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• 2009

This paper describes the mechanical properties of poly (Polycrystalline) 3C-SiC thin films with $N_2$ in-situ doping. In this work, the poly 3C-SiC film was deposited by APCVD (Atmospheric Pressure Chemical Vapor Deposition) method using single-precursor HMDS (Hexamethyildisilane: $Si_2(CH_3)_6)$ at $1200^{\circ}C$. The mechanical properties of doped poly 3C-SiC thin films were measured by nono-indentation according to the various $N_2$ flow rate. In the case of 0 sccm $N_2$ flow rate, Young's Modulus and hardness were obtained as 285 GPa and 35 GPa, respectively. Young's Modulus and hardness were decreased according to increase of $N_2$ flow rate. The crystallinity and surface roughness was also measured by XRD (X-Ray Diffraction) and AFM (Atomic Force Microscopy), respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.11a
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• pp.97-100
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• 1994

The present paper is devoted to the physical and electrical characteristics of N-docosyl- quinolinium-TCNQ films compared with the films doped with I$_2$. Iodine affects the degree of charge transfer and the conductivity of the films. The UV-visible absorption spectra of the film doped with I$_2$ shows that the peak of I$_3$ which had electronic transition at 300∼350nm and (TCNQ-)$_2$ dimer absorption disappered. The in-plane electrical conductivity of the films doped with I$_2$ were 1.4${\times}$10$\sub$-6/S/cm, which is two orders of magnitude higher conductivity than undoped LB films. The film structural difference between Y and Z-type may cause the conductivity. Another possible reasons of the structural difference was the overlapping TCNQ anion radical in LB films.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.1
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• pp.19-22
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• 1999

N-doped and low-hydrogenated DLC thin films were coated on the Mo-tip FEAs in order to improve the field emission performance and their electrical properties were evaluated. The fabricated devices showed improved field emission performance in terms of turn-on voltage, emission current and current fluctuation. This result might be caused both by the shift of Fermi level toward conduction band by N-doping and by the inherent stability of DLC material. Furthermore, the transconductance of the DLC-coated Mo-tip FEA and electrical conductivity and optical band-gap of the deposited DLC films were investigated.