• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제53권10호
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• pp.495-499
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• 2004

Characteristics of ohmic Ni/Si/Ni contacts to n-type 4H-SiC are investigated systematically. The ohmic contacts were formed by annealing Ni/Si/Ni sputtered sequentially The annealings were performed at 950℃ using RTP in vacuum ambient and N₂ ambient, respectively. The specific contact resistivity(p/sub c/), sheet resistance(R/sub s/), contact resistance (R/sub c/) transfer length(L/sub T/) were calculated from resistance(R/sub T/) versus contact spacing(d) measurements obtained from TLM(transmission line method) structure. While the resulting measurement values of sample annealed at vacuum ambient were p/sub c/ = 3.8×10/sup -5/Ω㎠, R/sub c/ = 4.9 Ω and R/sub T/ = 9.8 Ω, those of sample annealed at N₂ ambient were p/sub c/ = 2.29×10/sup -4/Ω㎠, R/sub c/ = 12.9 Ω and R/sub T/ = 25.8 Ω. The physical properties of contacts were examined using XRD 3nd AES. The results showed that nickel silicide was formed on SiC and Ni was migrated into SiC. This result indicates that Ni/Si/Ni ohmic contact would be useful in high performance electronic devices.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 제5회 영호남 학술대회 논문집
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• pp.59-62
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• 2003

Our Zn diffusion into n-type $GaAs_{0.60}P_{0.40}$ used ampoule-tube method to increase IV. N-type epitaxial wafers were preferred by $H_2SO_4$-based pre-treatment. $SiO_2$ thin film was deposited by PECVD for some wafers. Diffusion times and diffusion temperatures respectability are 1, 2, 3 hr and 775, $805^{\circ}C$. LED chips were fabricated by the diffused wafers at Fab. The peak wavelength of all chips showed about 625~650 nm and red color. The highest IV is about 270 mcd at the diffusion condition of $775^{\circ}C$, 3h for the wafers which didn't deposit $SiO_2$ thin films. Also, the longer diffusion time is the higher IV for the wafers which deposit $SiO_2$ thin films.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.15-16
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• 2008

We have grown N-doped ZnO thin films on sapphire substrate by employing dielectric barrier discharge in pulsed laser deposition (DBD-PLD). DBD guarantees an effective way for massive in-situ generation of N-plasma under the conventional PLD process condition. Low-temperature photoluminescence spectra of the N-doped ZnO film provided near band-edge emission after thermal annealing process. The emission peak was resolved by Gaussian fitting and showed a dominant acceptor-bound exciton peak ($A^0X$) that indicated the successful p-type doping of ZnO with N.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.312-312
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• 2013

GaN based light emitting diodes (LEDs) are important devices that are being used extensively in our daily life. For example, these devices are used in traffic light lamps, outdoor full-color displays and backlight of liquid crystal display panels. To realize high-brightness GaN based LEDs for solid-state lighting applications, the development of p-type ohmic electrodes that have low contact resistivity, high optical transmittance and high refractive index is essential. To this effect, indiumtin oxide (ITO) have been investigated for LEDs. Among the transparent electrodes for LEDs, ITO has been one of the promising electrodes on p-GaN layers owing to its excellent properties in optical, electrical conductivity, substrate adhesion, hardness, and chemical inertness. Sputtering and e-beam evaporation techniques are the most commonly used deposition methods. Commonly, ITO films on p-GaN by sputtering have better transmittance and resistivity than ITO films on p-GaN by e-bam evaporation. However, ITO films on p-GaN by sputtering have higher specific contact resistance, it has been demonstrated that this is due to possible plasma damage on the p-GaN in the sputtering process. In this paper, we have investigated the advanced sputtering using plasma damage-free p-electrode. Prepared the ITO films on the GaN based LEDs by e-beam evaporation, normal sputtering and advanced sputtering. The ITO films on GaN based LEDs by sputtering showed better transmittance and sheets resistance than ITO films on the GaN based LEDs by e-beam evaporation. Finally, fabricated of GaN based LEDs by using advanced sputtering. And compared the electrical properties (measurement by using C-TLM) and structural properties (HR-TEM and FE-SEM) of ITO films on GaN based LEDs produced by e-beam evaporation, normal sputtering and advanced sputtering. As a result, It is expected to form plasma damage free-electrode, and better light output power and break down voltage than LEDs by e-beam evaporation and normal sputter.

• 한국전기전자재료학회논문지
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• 제22권11호
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• pp.910-917
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• 2009

We have designed a new structures of Junction Field Effect Transistor(JFET) using SILVACO simulation to improve electrical properties and process reliability. The device structure and process conditions of Si control JFET(Si JFET) were determined to set cut off voltage and drain current(at Vg=0 V) to -0.46 V and $300\;{\mu}A$, respectively. Among many design parameters influencing the performance of the device, the drive-in time of p-type gate is presented most predominant effects. Therefore we newly designed SiGe JFET, in which SiGe layers were placed above and underneath of Si-channel. The presence of SiGe layer could lessen Boron into the n-type Si channel, so that it would be able to enhance the structural consistency of p-n-p junction. The influence of SiGe layer could be explained in conjunction with boron diffusion and corresponding I-V characteristics in comparison with Si-control JFET.

• 한국재료학회지
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• 제8권10호
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• pp.931-937
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• 1998

순수한 Rutile에서 점결함의 형태와 전기적 특성을 연구하기 위해 $1~10{-23}$atm의 산소분압 범위 및 $700~1300^{\circ}C$의 온도 범위에서 전기전도도를 측정하였다. 전기전도도의 산소분압 의존성($log\sigma/logPo_2$)으로부터 산소분압 및 온도 변화에 따라 다음과 같은 지배적인 결함들을 제안한다. 1) $Ti_nO_{2n-1}$, 2)침입형 Ti 이온 3)2가로 하전된 산소빈자리 4)불순물에 의해 형성된 2가로 하전된 산소빈자리 5) n-p전이 및 p형 전도 또한, 고유범위의 실험결과로부터 계산한 Ti와 Vo의 결함형성 엔탈피는 각각, 10.2eV와 4.92eV였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.442-443
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• 2007

Al-N co-doped ZnO films were fabricated on n-Si (100) and homo-buffer layers in the mixture of oxygen and nitrogen at $450^{\circ}C$ by magnetron sputtering. Target was ZnO ceramic mixed with $2wt%Al_2O_3$. XRD spectra show that as-grown and $600^{\circ}C$ annealed films are prolonged along crystal c-axis. However they are not prolonged in (001) plane vertical to c-axix. The films annealed at $800^{\circ}C$ are not prolonged in any directions. Codoping makes ZnO films unidirectional variation. XPS show that Al content hardly varies and N escapes with increasing annealing temperature from $600^{\circ}C\;to\;800^{\circ}C$. The electric properties of as-grown films were tested by Hall Effect with Van der Pauw configuration show some of them to be p-type conduction.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.131-131
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• 2008

Silicon carbide (SiC) has attracted significant attention for high frequency, high temperature and high power devices due to its superior properties such as the large band gap, high breakdown electric field, high saturation velocity and high thermal conductivity. We performed Al ion implantation processes on n-type 4H-SiC substrate using a SILVACO ATHENA numerical simulator. The ion implantation model used a Monte-Carlo method. We studied the effect of channeling by Al implantation simulation in both 0 off-axis and 8 off-axis n-type 4H-SiC substrate. We have investigated the Al distribution in 4H-SiC through the variation of the implantation energies and the corresponding ratio of the doses. The implantation energies controlled 40, 60, 80, 100 and 120 keV and the implantation doses varied from $2\times10^{14}$ to $1\times10^{15}cm^{-2}$. In the simulation results, the Al ion distribution was deeper as increasing implantation energy and the doping level increased as increasing implantation doses. After the post-implantation annealing, the electrical properties of Al-implanted p-n junction diode were investigated by SILV ACO ATLAS numerical simulator.

• 한국전기전자재료학회논문지
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• 제20권10호
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• pp.883-888
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• 2007

Investigation of improving the properties of UV detector which uses the wide bandgap of ZnO are under active progress. The present study focused on the design and fabrication of i-ZnO/p-inversion $layer/n^--Si$ Epi. which is characterized with very thin p-type inversion layer for UV detectors. The i-ZnO thin film for achieving p-inversion layer which was grown by RF sputtering at $450^{\circ}C$ and then annealed at $400^{\circ}C$ in $O_2$ gas for 20 min shows good intrinsic properties. High (0002) peak intensity of the i-ZnO film is shown on XRD spectrum and it is confirmed by XPS analysis that the ratio of Zn : O of the i-ZnO film is nearly 1 : 1. Measurement shows high transmission of 79.5 % in UV range (< 400 nm) for the i-ZnO film. Measurement of $V_r-I_{ph}$ shows high UV photo-current of 1.2 mA under the reverse bias of 30 V.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.510-513
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• 2003

Our Zn diffusion into n-type $GaAs_{0.40}P_{0.60}$ used ampoule-tube method to increase IV. N-type epitaxial wafers were preferred by $H_2SO_4$-based pre-treatment. $SiO_2$ thin film was deposited by PECVD for some wafers. Diffusion times and diffusion temperatures respectability are 1, 2, 3 hr and 775, $805^{\circ}C$. LED chips were fabricated by the diffused wafers at Fab. The peak wavelength of all chips showed about $625{\sim}650\;nm$ and red color. The highest IV is about 270 mcd at the diffusion condition of $775^{\circ}C$, 3h for the wafers which didn't deposit $SiO_2$ thin films. Also, the longer diffusion time is the higher IV for the wafers which deposit $SiO_2$ thin films.