• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.11a
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• pp.11-17
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• 2000

The electric contact resistance between ball and disk was measured to estimate the real area of contact under dry and lubrication conditions. The results from the measured constriction resistance using the hypothesis of a single circular contact was compared with those of Hertzian contact theory and hardness. The resistance correlated well with the asperity contact area and friction when the ball slides on the flat disk spreaded with lubricant film. Therefore, the constriction resistance method was useful to identify the lubrication regimes with respect to various loads and speeds. The results of this work will aid in better prediction of lubrication regimes with respect to the operating conditions.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.2
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• pp.210-214
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• 2016

In this paper, the decrease in the contact resistance of Ni germanide/Ge contact was studied as a function of the thickness of the antimony (Sb) interlayer for high performance Ge MOSFETs. Sb layers with various thickness of 2, 5, 8 and 12 nm were deposited by RF-Magnetron sputter on n-type Ge on Si wafers, followed by in situ deposition of 15nm-thick Ni film. The contact resistance of samples with the Sb interlayer was lower than that of the reference sample without the Sb interlayer. We found that the Sb interlayer can lower the contact resistance of Ni germanide/Ge contact but the reduction of contact resistance becomes saturated as the Sb interlayer thickness increases. The proposed method is useful for high performance n-channel Ge MOSFETs.

• Carbon letters
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• v.14 no.3
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• pp.171-174
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• 2013

The high quality contact between graphene and the metal electrode is a crucial factor in achieving the high performance of graphene transistors. However, there is not sufficient research about contact resistance reduction methods to improve the junction of metal-graphene. In this paper, we propose a new method to decrease the contact resistance between graphene and metal using directly grown graphene over a metal surface. The study found that the grown graphene over copper, as an intermediate layer between the copper and the transferred graphene, reduces contact resistance, and that the adhesion strength between graphene and metal becomes stronger. The results confirmed the contact resistance of the metal-graphene of the proposed structure is nearly half that of the conventional contact structure.

• Journal of the Korean Institute of Telematics and Electronics
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• v.20 no.1
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• pp.50-54
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• 1983

Contact resistance variation which may be called sliding noise in carbon film variable resistors whose resistance elements consists of linear resistivity distribution were measured with several kinds of sliders and were analyzed to reduce the contact resistance variation. About the measuring method, the standard method of measuring contact resistance variation specified by the variable Resistance Components Institute was adupted. By analyzing the experimental results, it has been shown that the primary cause of contact resistance variation is due to current constriction and small discharge sparks in the resistance film in the area close to the slide contact. Moreover, it has been found that the sliding noise would be reduced by increasing the number of contact points, sliding speed, and pressure, and by using some kinds of insulation oil on the contacting surface. High contact resistance variation is likely to occur in the area of high resistance variation in a logrithmic resistance taper.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.404-409
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• 2004

The electrical contact resistance is here estimated using the multiscale microcontact distribution of elastic contact between rough surfaces, simulated from the Archard's model, and the electrical contact conduction theory suggested by Greenwood. These analysis confirms that the electrical contact resistance is converged to a values, larger than would be obtained if the contact spots were widely separated and hence independent. In multiscale process, the base potential is close to the value of the potential difference between the contact surface and the extremity of body, suggesting a possibility to obtain the multiscale electrical contact resistance relations.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.3 no.4
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• pp.256-262
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• 1991

The corrosion effects on thermal contact resistance were experimentally studied for a given contact interface of a couple of metals. 2 cylindrically shaped test pieces, the one was carbon steel whose surface was machined by lathe and the other was stainless steel, ground, were come into contact under pressure, and then submerged to $HNO_3$ gas environment. While the corrosion process was going on, the thermal contact resistance was measured with time. The experiment was performed for 2 cases; 1) Highly compress the test pieces and then bring them to $HNO_3$ gas environment. 2) Anteriorly corrode the interface under low contact pressure and then increase the contact pressure. The results were as follows; In 1st. case of experiment, the thermal contact resistance seemed to be very stable, and showed low values with a tendancy of small decrease with time. But in 2nd. case the resistance was unstable and jumped to a value of 200-250% more then that expected for uncontaminated interface. More over it demonstrated some increase with time.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.279-282
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• 2002

In this paper, we discuss influence of process condition on contact resistance in WSix deposition process. In the WSix deposition process, we confirmed that word line to bit line contact resistance(WBCR) due to temperature of word line WSix deposition among various process condition split experiment. RTP treatment, d-poly ion implantation dose and thickness was estimated a little bit influence on contact resistance. Also, life time of shower head in the process chamber for WSix deposition related to contact resistance. The results obtained in this study are applicable to process control and electrical characteristics for high reliability and high density DRAM's.

• Journal of the Korean Ceramic Society
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• v.33 no.11
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• pp.1231-1236
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• 1996

The electrode resistance of semiconducting PTC BaTiO3 ceramic material was studied in some detail. Comme-rical In-Ag paste In-Ga alloy and electroless plated Ni as well as evaporated Al were chosen as electrode. The contact resistance of electroded samples were measured by both dc resistivity and ac impedance analysis. The aging effect on contact resistance under cyclic loading from -1$0^{\circ}C$ to 85$^{\circ}C$ was also monitored for the prolonged period of time. In case of Al electroded samples the heat treatment and protective coating had effects on the stability against contact resistance degradation. It was also found that the samples with commercial In-Ag paste and electroless plated Ni electrode had good properties of contact resistance against aging.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.348-348
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• 2011

Carbon nanotube (CNT) field effect transistors and sensors use CNT as a current channel, of which the resistance varies with the gate voltage or upon molecule adsorption. Since the performance of CNT devices depends very much on the CNT/metal contact resistance, the CNT/electrode contact must be stable and the contact resistance must be small. Depending on the geometry of CNT/electrode contact, it can be categorized into the end-contact, embedded-contact (top-contact), and side-contact (bottom-contact). Because of difficulties in the sample preparation, the end-contact CNT device is seldom practiced. The embedded-contact in which CNT is embedded inside the electrode is desirable due to its rigidness and the low contact resistance. Fabrication of this structure is complicated, however, because each CNT has to be located under a high-resolution microscope and then the electrode is patterned by electron beam lithography. The side-contact is done by depositing CNT electrophoretically or by precipitating on the patterned electrode. Although this contact is fragile and the contact resistance is relatively high, the side-contact by far has been widely practiced because of its simple fabrication process. Here we introduce a simple method to embed CNT inside the electrode while taking advantage of the bottom-contact process. The idea is to utilize a eutectic material as an electrode, which melts at low temperature so that CNT is not damaged while annealing to melt the electrode to embed CNT. The lowering of CNT/Au contact resistance upon annealing at mild temperature has been reported, but the electrode in these studies did not melt and CNT laid on the surface of electrode even after annealing. In our experiment, we used a eutectic Au/Al film that melts at 250$^{\circ}C$. After depositing CNT on the electrode made of an Au/Al thin film, we annealed the sample at 250$^{\circ}C$ in air to induce eutectic melting. As a result, Au-Al alloy grains formed, under which the CNT was embedded to produce a rigid and low resistance contact. The embedded CNT contact was as strong as to tolerate the ultrasonic agitation for 90 s and the current-voltage measurement indicated that the contact resistance was lowered by a factor of 4. By performing standard fabrication process on this CNT-deposited substrate to add another pair of electrodes bridged by CNT in perpendicular direction, we could fabricate a CNT cross junction. Finally, we could conclude that the eutectic alloy electrode is valid for CNT sensors by examine the detection of Au ion which is spontaneously reduced to CNT surface. The device sustatined strong washing process and maintained its detection ability.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.82-84
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• 2003

In case contact between point of contacts is not achieved well, contact resistance is grown, and by current concentration at current conducting contacts can weld. In order to decrease contact resistance between contacts in case of busbar, installing spring between fixed contact and moving contact. and then force on faying surface of contacts increase and contact resistance decrease. But, in case increase force of spring to widen contact area, operating force moving contact can grow, on the contrary force of spring is small, contact resistance becomes low. Therefore, need to optimize force and number of spring. position, and also need to examine force change on contact surface at point of contact moving. In this paper, dynamic kinetics analysis for force on faying surface of contacts is performed at unsteady state. It is showed to not uniform force on surface between contacts, and we can got more uniform force by means of change spring position.