A carbon-based hybrid resistor was fabricated using carbon nanotube (CNT) paste as an adhesive layer to establish electrically continuous ohmic contacts between CNT sheets and different CNT sheet or copper based metal alloy plates, and its electrical properties were evaluated. CNT sheets were fabricated using vacuum filtration with a CNT solution dispersed in isopropyl alcohol (IPA) solvent. The electrical characteristics of these carbon-based hybrid resistors were investigated.The CNT paste fulfilled the requirements for forming ohmic contacts between CNT sheets and metal alloy plates, which was attributed to the lowest work function difference and excellent wettability at the interface.

We prepared carbon nanotube (CNT) paper by a vacuum filtration method for the use of a chip-typed resistor as a precision passive device with a constant resistance. Hybrid resistor composed of the CNT resistor with a negative temperature coefficient of resistance (T.C.R) and a metal alloy resistor with a positive T.C.R could lead to a constant resistance, because the resistance increase owing to the temperature increase at the metal alloy and decrease at the CNT could counterbalance each other. The constant resistance for the precision passive devices should be maintained even when a heat was generated by a current flow resulting in resistance change. Performance reliabilities of the CNT resistor for the precision passive device applications such as electrical load limit, environmental load limit, and life limit specified in IEC 60115-1 must be ensured. In this study, therefore, the rated power determination and T.C.R tests of the CNT paper were conducted. -900~-700 ppm/℃ of TCR, 0.1~0.2 A of the carrying current capacity, and 0.0625~0.125 W of the rated power limit were obtained from the CNT paper. Consequently, we confirmed that the application of CNT materials for the precision hybrid passive devices with a metal alloy could result in a better performance reliability with a zero tolerance.

In this study, we fabricated plate-type shunt resistors with thermal stability by parallelly connecting metal alloy plates with positive temperature coefficient of resistance (TCR) and carbon nanotube (CNT) plates with negative TCR. The metal alloy plates, which were prepared by alloying Cu and Mn with a composition of 91 wt% of Cu and 9 wt% of Mn, showed around 800 ppm/℃ of TCR, and the CNT plates prepared from the CNT solution by using the vacuum filtration method showed around -800 ppm/℃ of TCR. The shunt resistor that was fabricated by stacking metal alloy plates and CNT plates in this work showed about 46.93 ppm/℃ of TCR. Therefore, we conclude that a shunt resistor with low TCR can be realized by simply adjusting the TCR of the metal alloy only, because the TCR of the CNT plate has an identical value.