• 태양에너지
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• 제17권1호
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• pp.59-66
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• 1997

개방전압과 단락전류와 같은 태양전지 출력변수들은 접합깊이, 도핑농도, 금속접합 및 태양전지구조에 의한 변수들이다. 태양전지 설계의 중요한 요소로서 인이 도핑된 에미터와 금속사이의 금속접합은 일함수 차이가 작아 낮은 직렬저항을 가져야 한다. PESC 태양전지는 금속 접합장벽 전극으로 티타늄을 사용한다. 새로운 접합장벽 전극물질로 티타늄과 일함수가 비슷하지만 전기전도도가 우수한 크롬은 금속 접합장벽 전극으로 유망한 금속이다. 티타늄은 일함수 차가 작지만, 접합장벽으로 크롬은 태양전지 제조시 티타늄보다 우수한 전기적 특성들을 갖는다. 본 논문에서는 실리콘 태양전지의 접합장벽 금속전극의 특성을 비교 분석하였다.

• E2M - 전기 전자와 첨단 소재
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• 제8권1호
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• pp.56-63
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• 1995

MESFETs of the Ti/Au and Ti/Pd/Au gate were fabricated on n-type GaAs. Interdiffusion at Schottky interfaces, Schottky contact properties, and MESFET characteristics with heat treatment were investigated. Ti of Ti/Au contact and Pd of Ti/Pd/Au contact acted as a barrier metal against interdiffusion of Au at >$220^{\circ}C$. Pd of Ti/Pd/Au contact acted as a barrier metal even at >$360^{\circ}C$, however, Ti of Ti/Au contact promoted interdiffusion of Au instead of role of barrier metal. As the heat treatment temperature increases, in the case of both contact, saturated drain current and pinch off voltage decreased, open channel resistance increased, and degree of parameter variation in Ti/Au gate was higher than in Ti/Pd/Au gate at >$360^{\circ}C$ Schottky barrier height of Ti/Au and Ti/Pd/Au contacts was 0.69eV and 0.68eV in the as-deposited state, respectively, and Fermi level was pinned in the vicinity of 1/2Eg. As the heat treatment temperature increases, barrier height of Ti/Pd/Au contact increased, however, decreased at >$360^{\circ}C$ in the case of Ti/Au contact. Ideality factor of Ti/Au contact was nearly constant regardless of heat treatment, however, increased at >$360^{\circ}C$ in the case of Ti/Au contact. From the results above, Ti/Pd/Au was stable gate metal than Ti/Au.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.571-574
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• 2009

Metal oxide/metal bilayer structures are explored as contacts with a low injection barrier in organic thin-film transistors (OTFTs) in an effort to realize their true potential for low-cost electronics. OTFTs with a bilayer electrode of $WO_3$ (10nm) and Al shows a saturation mobility as large as 0.97 $cm^2$/Vsec which are comparable to those of Au-based control samples (~0.90 $cm^2$/Vsec). Scaling of contact resistance with respect to the thickness of $WO_3$ layer is also discussed.

• 한국전기전자재료학회논문지
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• 제23권7호
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• pp.575-579
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• 2010

The technologies of Ni/Cu plating contact is attributed to the reduced series resistance caused by a better contact conductivity of Ni with Si and the subsequent electroplating of Cu on Ni. The ability to pattern narrower grid lines for reduced light shading was combined with the lower resistance of a metal silicide contact and an improved conductivity of the plated deposit. This improves the FF (fill factor) as the series resistance is reduced. This is very much requried in the case of low concentrator solar cells in which the series resistance is one of the important and dominant parameter that affect the cell performance. A Selective emitter structure with highly dopeds regions underneath the metal contacts, is widely known to be one of the most promising high-efficiency solution in solar cell processing In this paper the formation of a selective emitter, and the nickel silicide seed layer at the front side metallization of silicon cells is considered. After generating the nickel seed layer the contacts were thickened by Cu LIP (light induced plating) and by the formation of a plated Ni/Cu two step metallization on front contacts. In fabricating a Ni/Cu plating metallization cell with a selective emitter structure it has been shown that the cell efficiency can be increased by at least 0.2%.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.91.2-91.2
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• 2010

The use of plated front contact for metallization of silicon solar cell may alternative technologies as a screen printed and silver paste contact. This technologies should allow the formation of contact with low contact resistivity a high line conductivity and also reduction of shading losses. The better performance of Ni/Cu contacts is attributed to the reduced series resistance due to better contact conductivity of Ni with Si and subsequent electroplating of Cu on Ni. The ability to pattern narrower grid lines for reduced light shading combined with the lower resistance of a metal silicide contact and improved conductivity of plated deposit. This improves the FF as the series resistance is deduced. This is very much required in the case of low concentrator solar cells in which the series resistance is one of the important and dominant parameter that affect the cell performance. A selective emitter structure with highly dopes regions underneath the metal contacts, is widely known to be one of the most promising high-efficiency solution in solar cell processing. This paper using selective emitter structure technique, fabricated Ni/Cu plating metallization cell with a cell efficiency of 17.19%.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.209.2-209.2
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• 2015

Two dimensional layered materials, such as transition metal dichalcogenides (TMDs) family have been attracted significant attention due to novel physical and chemical properties. Among them, molybdenum disulfide ($MoS_2$) has novel physical phenomena such as absence of dangling bonds, lack of inversion symmetry, valley degrees of freedom. Previous studies have shown that the interface of metal/$MoS_2$ contacts significantly affects device performance due to presence of a scalable Schottky barrier height at their interface, resulting voltage drops and restricting carrier injection. In this study, we report a new device structure by using few-layer graphene as the bottom interconnections, in order to offer Schottky barrier free contact to bi-layer $MoS_2$. The fabrication of process start with mechanically exfoliates bulk graphite that served as the source/drain electrodes. The semiconducting $MoS_2$ flake was deposited onto a $SiO_2$ (280 nm-thick)/Si substrate in which graphene electrodes were pre-deposited. To evaluate the barrier height of contact, we employed thermionic-emission theory to describe our experimental findings. We demonstrate that, the Schottky barrier height dramatically decreases from 300 to 0 meV as function of gate voltages, and further becomes negative values. Our findings suggested that, few-layer graphene could be able to realize ohmic contact and to provide new opportunities in ohmic formations.

• 한국전기전자재료학회논문지
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• 제24권2호
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• pp.152-155
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• 2011

Even though nano-scale materials were very advantageous for various applications, there are still problems to be solved such as the stabilization of surface state and realization of low contact resistances between a semiconducting nanowire and electrodes in nano-electronics. It is well known that the effects of contacts barrier between nano-channel and metal electrodes were dominant in carrier transportation in individual nano-electronics. In this report, it was investigated the electrical properties of GaN nanorod devices after chemical etching and rapid thermal annealing for making good contacts. After KOH wet-etching of the contact area the devices showed better electrical performance compared with non-treated GaN individual devices but still didn't have linear voltage-current characteristics. The shape of voltage-current properties of GaN devices were improved remarkably after rapid thermal annealing as showing Ohmic behaviors with further bigger conductivities. Even though chemical etching of the nanorod surfaces could cause scattering of carriers, in here it was shown that the most important and dominant factor in carrier transport of nano-electronics was realization of low contact barrier between nano-channel and metal electrodes surely.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 광주전남지부
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• pp.87-90
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• 2006

Two SiC radiation detector samples were irradiated by Co-60 gamma rays. The irradiation was performed with dose rates of 5 kGy/hour and 15 kGy/hour for 8 hours, respectively. Metal/semiconductor contacts on the surface were fabricated by using a thermal evaporator in a high vacuum condition. The SiC detectors have metal contacts of Au(2000 ${\AA}$)/Ni(300 ${\AA}$) at Si-face and of Au(2000 ${\AA}$)/Ti(300 ${\AA}$) at C-face. I-V characteristics of the SiC semiconductor were measured by using the Keithley 4200-SCS parameter analyzer with voltage sources included. From the I-V curve, we analyzed the Schottky barrier heights(SBHs) on the basis of the thermionic emission theory. As a result, the 6H-SiC semiconductor showed- similar Schottky barrier heights independent to the dose rates of the irradiation with Co-60 gamma rays.

• JSTS:Journal of Semiconductor Technology and Science
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• 제3권1호
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• pp.1-12
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• 2003

This paper describes a study on the abnormal behavior of the electrical characteristics of the (n)GaAs/Ti/Pt/Au Schottky contacts prepared by the two techniques of electron beam deposition and rf sputtering and after an annealing treatment. The samples were characterized by I-V and C-V measurements carried out over the temperature range of 150 - 350 K both in the as prepared state and after a 300 C, 30 min. anneal step. The variation of ideality factor with forward bias, the variation of ideality factor and barrier height with temperature and the difference between the capacitance barrier and current barrier show the presence of a thin interfacial oxide layer along with barrier height inhomogenieties at the metal/semiconductor interface. This barrier height inhomogeneity model also explains the lower barrier height for the sputtered samples to be due to the presence of low barrier height patches produced because of high plasma energy. After the annealing step the contacts prepared by electron beam have the highest typical current barrier height of 0.85 eV and capacitance barrier height of 0.86 eV whereas those prepared by sputtering (at the highest power studied) have the lowest typical current barrier height of 0.67 eV and capacitance barrier height of 0.78 eV.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.657-657
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• 2013

In-situ observations of nano-scale behavior of nanomaterials are very important to understand onthe nano-scale phenomena associated with phase change, atomic movement, electrical or optical properties, and even reactions which take place in gas or liquid phases. We have developed on the in-situ experimental technologies of nano-materials (nano-cluster, nanowire, carbon nanotube, and graphene, et al.) and their interactions (percolation of metal nanoclusters, inter-diffusion, metal contacts and phase changes in nanowire devices, formation of solid nano-pores, melting behavior of isolated nano-metal in a nano-cup, et al.) by nano-discovery membrane platform [1-4]. Between two microelectrodes on a silicon nitride membrane platform, electrical percolations of metal nano-clusters are observed with nano-structures of deposited clusters. Their in-situ monitoring can make percolation devices of different conductance, nanoclusters based memory devices, and surface plasmonic enhancement devices, et al. As basic evidence on the phase change memory, phase change behaviors of nanowire devices are observed at a nano-scale.