• Bulletin of the Korean Chemical Society
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• 제11권1호
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• pp.11-15
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• 1990

The temperature dependence of electrical conductivities and thermoelectric power of $I_2$-doped poly(1,4-penylene vinylene-co-2,5-dimethoxy-1,4-phenylene vinylene)s [poly(PV-co-DMPV)] and poly(1,4-phenylene vinylene-co-2,5-thienylene vinylene)s [poly(PV-co-TV)] were studied. The former copolymers were also doped with $FeCl_3$. All the samples used were in thin film forms. The temperature dependence of electrical conductivity implies that the variable range hopping conduction mechanism applises to these systems. The activation energy for the electrical conduction in dimethoxy-phenylene vinylene (DMPV) copolymers ranged from about 7 to 30 meV depending on the polymer composition and the nature of the dopant. It was significantly higher for $I_2$-doped thienylene vinylene (TV) copolymers, namely 90-200 meV. The values of the room temperature thermoelectric power were $30-70{\mu}V/K$ for DMPV copolymer and $100-800{\mu}V/K$ for TV copolymers. Anisotropy in the electrical conductivities was also studied for oriented films obtained by uniaxial stretching of the precursor polymer films.

• 한국재료학회지
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• 제1권3호
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• pp.132-138
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• 1991

2충의 BPSG를 사용하는 서브마이크론 CMOS DRAM에 있어 전기적 특성에 관한 BPSG flow온도의 영향을 비교하였다. BPSG flow온도를 $850^{\circ}C/850^{\circ}C,\;850^{\circ}C/900^{\circ}C,\;900^{\circ}C/900^{\circ}C$의 3가지 다른 조합을 적용하여 문턱전압, 파괴전압, Isolation전압과 더불어 면저항과 접촉 저항을 조사하였다. $900^{\circ}C/900^{\circ}C$ flow의 경우 NMOS에서 문턱전압은 $0.8\mu\textrm{m}$ 미만의 채널길이에서 급격히 감소하나 PMOS 경우는 차이가 없었다. NMOS와 PMOS의 파괴전압은 각각 $0.7\mu\textrm{m}$와 $0.8\mu\textrm{m}$ 이하에서 급격히 감소하였다. 그러나 $850^{\circ}C/850^{\circ}C$ flow의 경우에는 NMOS와 PMOS모두 문턱전압과 파괴전압은 채널길이 $0.7\mu\textrm{m}$까지 감소하지 않았다. Isolation전압은 BPSG flow온도 감소에 따라 증가하였다. 면저항과 접촉 저항은 BPSG flow온도가 $900^{\circ}C$에서 $850^{\circ}C$로 감소됨에 따라 급격히 증가되었다. 이와 같은 결과는 열처리 온도에 따라 dopant의 확산과 활성화에 관련 있는 것으로 생각된다. 접촉 저항 증가에 대한 개선 방법에 대하여 고찰하였다.

• 한국진공학회지
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• 제11권3호
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• pp.151-158
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• 2002

Decaborane ($B_{10}H_{14}$) 이온 주입법으로 n-type Si (100) 기판에 ultra-shallow $p^{+}-n$ 접합을 형성시켰다. 이온 주입에너지는 5kV와 10kV, 이온 선량은 $1\times10^{12}\textrm{cm}^2$와 $1\times10^{13}\textrm{cm}^2$로 decaborane을 이온 주입시켰다. 이온 주입된 시료들은 $N_2$ 분위기에서 $800^\{\circ}C$, $900^{\circ}C$, $1000^{\circ}C$에서 10초 동안 RTA(Rapid Thermal Annealing) 처리를 하였다. 또한 가속에너지에 따른 결함을 확인하기 위해서 15 kV의 이온 주입 에너지에서 $1\times10^{14}\textrm{cm}^2$만큼 이온 주입하였다. 2 MeV $^4He^{2+}$ channeling spectra에서 15 kV로 주입된 시료가 bare n-type Si와 5 kV, 10 kV의 에너지로 주입된 시료보다 주입시 생긴 결함에 의해 backscattering yield가 더 높게 나타났으며 spectra로부터 얻은 이온 주입으로 인한 비정질층의 두께는 표면으로부터 가속전압이 5kV, 10kV, 15kV일 때 각각 1.9nm, 2.5nm, 4.3nm였다. 10 kV에서 이온 주입된 시료를 $800^{\circ}C$ 열처리 한 결과 결함의 회복으로 인해 bare Si와 비슷한 backscattering yield를 보였으며 이때의 계산된 비정질 층의 두께는 0.98 nm이었다. 홀 측정과 면저항 측정은 dopant의 활성화가 주입된 에너지, 이온 선량, 열처리 온도에 따라 증가함을 보여주었다. I-V 측정 결과 누설 전류 밀도는 열처리 온도가 $800^{\circ}C$에서 $1000^{\circ}C$까지 증가함에 따라 감소하였고 주입에너지가 5kV에서 10kV까지 증가함에 따라 증가하였다.

• 한국전기전자재료학회논문지
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• 제24권12호
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• pp.962-968
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• 2011

In this study, we investigated the effects of Mn dopant (0.1~3.0 at% $Mn_3O_4$ sintered at 1000$^{\circ}C$ for 1 h in air) on the bulk trap (i.e. defect) and grain boundary properties of ZnO, ZM(0.1~3.0) using admittance spectroscopy (AS), and impedance-modulus spectroscopy (IS & MS). As a result, three kinds of defect were found below the conduction band edge of ZnO as 0.09~0.14 eV (attractive coulombic center), 0.22~25 eV ($Zn^{{\cdot}{\cdot}}_i$), and 0.32~0.33 eV ($V^{\cdot}_o$). The oxygen vacancy increased with Mn doping. In ZM, an electrically single grain boundary as double Schottky barrier was formed with 0.82~1.0 eV of activation energies by IS & MS. We also find out that the barriers of grain boundary of Mn-doped ZnO (${\alpha}$-factor=0.13) were more stabilized and homogenized with temperature compared to pure ZnO.

• 대한전자공학회논문지
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• 제25권11호
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• pp.1342-1349
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• 1988

플리즈마 변수로서 가스조성과 압력 및 RF 전력이 인 및 붕소가 각각 다른 양으로 주입된 다결정 실리콘의 식각율 변화에 미치는 영향을 고찰하였다. $POCl_3$에 의해 인이 주입된 경우, 염소조성보다 불소조성이 많은 영역, 즉 $Cl_2$와 $SF_4$의 비가 17대 33일 때, 가장 큰 비등방성과 가장 작은 선폭손실을 달성하였다. 플라즈마 조건에 관계없이 주입된 불순물 농도의 증가에 다라, 인이 주입된 경우는 식각율이 증가하였고, 붕소가 주입된 경우는 식각율이 반대로 감소하였다. 또한, 급속 열처리에 의한 활성화 시간의 함수로서 인이 주입된 다결정실리콘의 식각율변화를 측정한 결과, 도우핑 농도뿐 아니라 활성화된 운반자, 즉 전자의 농도가 그 식각율 증가에 중요한 역할을 한다는 것을 확인하였다.

• 한국세라믹학회지
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• 제44권12호
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• pp.655-659
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• 2007

Zirconia polycrystals co-doped with x mol% CaO and (10-x) mol% $Y_2O_3$ were prepared by solid state reaction method. The compositions were chosen for nominally the same oxygen vacancy concentration of 5 mol%. X-ray diffraction patterns indicated the formation of cubic zirconia by heat treatment at $1600^{\circ}C$. Impedance spectroscopy was applied to deconvolute the bulk and grain boundary response. Electrical conductivity was measured using the complex impedance technique from 516 to 874 K in air. Maximum conductivity was exhibited by the composition with equal amounts of CaO and $Y_2O_3$, which may be ascribed to the smaller degree of defect-interactions in that composition due to the competition of different ordering schemes between the two systems. When compared to the composition containing $Y_2O_3$ only, co-doping of CaO increases the grain boundary resistance considerably. The activation energy of grain and grain boundary conductivity was 1.1 eV and 1.2 eV, respectively, with no appreciable dependence on dopant compositions.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.358-361
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• 2002

Self-aligned MOSFETS using a polysilicon gate are widely fabricated in silicon technology. The polysilicon layer acts as a mask for the source and drain implants and does as gate electrode in the final product. However, the usage of polysilicon gate as a self-aligned mask is restricted in fabricating SiC MOSFETS since the following processes such as dopant activation, ohmic contacts are done at the very high temperature to attack the stability of the polysilicon layer. A metal instead of polysilicon can be used as a gate material and even can be used for ohmic contact to source region of SiC MOSFETS, which may reduce the number of the fabrication processes. Co-formation process of metal-source/drain ohmic contact and gate has been examined in the 4H-SiC based vertical power MOSFET At low bias region (<20V), increment of leakage current after RTA was detected. However, the amount of leakage current increment was less than a few tens of ph. The interface trap densities calculated from high-low frequency C-V curves do not show any difference between w/ RTA and w/o RTA. From the C-V characteristic curves, equivalent oxide thickness was calculated. The calculated thickness was 55 and 62nm for w/o RTA and w/ RTA, respectively. During the annealing, oxidation and silicidation of Ni can be occurred. Even though refractory nature of Ni, 950$^{\circ}C$ is high enough to oxidize it. Ni reacts with silicon and oxygen from SiO$_2$ 1ayer and form Ni-silicide and Ni-oxide, respectively. These extra layers result in the change of capacitance of whole oxide layer and the leakage current

• 한국전기전자재료학회논문지
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• 제24권11호
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• pp.882-889
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• 2011

In this study, we have investigated the effects of Co doping on I-V curves, bulk trap levels and grain boundary characteristics of ZnO-$Bi_2O_3$ (ZB) varistor. From I-V characteristics the nonlinear coefficient (a) and the grain boundary resistivity (${\rho}_{gb}$) decreased as 32${\rightarrow}$22 and 18.4${\rightarrow}0.6{\times}10^9{\Omega}cm$ with sintering temperature (900~1,300$^{\circ}C$), respectively. Admittance spectra and dielectric functions show two bulk traps of zinc interstitial, $Zn_i^{{\cdot}{\cdot}}$(0.16~0.18 eV) and oxygen vacancy, $V_o^{{\cdot}}$ (0.28~0.33 eV). The barrier of grain boundaries in ZBCo (ZnO-$Bi_2O_3-Co_3O_4$) could be electrochemically single type. However, its thermal stability was slightly disturbed by ambient oxygen because the apparent activation energy of grain boundaries was changed from 0.93 eV at the 460~580 K to 1.13 eV at the 620~700 K. It is revealed that Co dopant in ZB reduced the heterogeneity of the barrier in grain boundaries and stabilized the barrier against the ambient temperature.

• 한국전기전자재료학회논문지
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• 제23권5호
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• pp.368-373
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• 2010

In this study, we have investigated the effects of Cr dopant on the bulk trap levels and grain boundary characteristics of $Bi_2O_3$-based ZnO (ZB) varistor using admittance spectroscopy and dielectric functions (such as $Z^*,\;Y^*,\;M^*,\;{\varepsilon}^*$, and $tan{\delta}$). Admittance spectra show more than two bulk traps of $Zn_i$ and $V_o$ probably in different ionization states in ZnO-$Bi_2O_3-Cr_2O_3$ (ZBCr) system. Three kinds of temperature-dependant activation energies ($E_{bt}'s$) were calculated as 0.11~0.14 eV of attractive coulombic center, 0.16~0.17 eV of $Zn_{\ddot{i}}$, and 0.33 eV of $V_o^{\cdot}$ as dominant bulk defects. The grain boundaries of ZBCr could be electrochemically divided into two types as a sensitive to ambient oxygen i.e. electrically active one and an oxygen-insensitive i.e. electrically inactive one. The grain boundaries were electrically single type under 460 K (equivalent circuit as parallel $R_{gb1}C_{gb1}$) but separated as double one ($R_{gb1}C_{gb1}-R_{gb2}C_{gb2}$) over 480 K. It is revealed that the dielectric functions are very useful tool to separate the overlapped bulk defect levels and to characterize the electrical properties of grain boundaries.

• 대한전자공학회논문지SD
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• 제47권4호
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• pp.13-19
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• 2010

중수소 결합이 존재하는 게이트 산화막을 갖는 MOSFET는 일반 MOSFET에 비해 신뢰성이 개선된다고 알려져 있다. 본 연구에서는 MOS 소자의 게이트 산화막내에 중수소를 분포시키기 위해 새로운 중수소 이온 주입법을 제안하였다. MOS 소자를 구성하는 층간 물질 및 중수소가 분포할 위치에 따라 중수소 이온 주입 에너지는 다양하게 변하게 된다. 이온 주입 후 발생할 수 있는 물질적 손상을 방지하기 위해 후속 열처리 공정이 수반된다. 제조된 일반 MOSFET를 사용하여 제안된 중수소이온 주입을 통해 게이트 산화막내 계면 및 bulk 결함이 감소함을 확인하였다. 그러나 이온 주입으로 인해 실리콘 기판의 불순물 농도가 변화할 수 있으므로 이온 주입 조건의 최적화가 필요하다. 중수소 이온 주입된 MOSFET의 CV 및 IV 특성 조사를 통해 이온 주입으로 인한 트랜지스터의 성능 변화는 발생하지 않았다.