Resistors, thick-film conduction mechanisms

Several kinds of conduction mechanisms are operative in ceramic thermistors, resistors, varistors, and chemical sensors. Negative temperature coefficient (NTC) thermistors make use of the semiconducting properties of heavily doped transition metal oxides such as tf-type Fe2 Ty03 and type Ni1 LyO. Thick film resistors are also made from transition-metal oxide solid solutions. Glass-bonded By 2 Pb2yRu207 having the pyrochlore [12174-36-6] structure is typical. 

The conduction mechanisms in thick-film resistors are very complex and have not yet been well defined. Mechanisms with metallic, semiconductor, and insulator properties have all been identified. High ohmic value resistors tend to have more of the properties associated with semiconductors, whereas low ohmic values tend to have more of the properties associated with conductors ... 

EHfferent conduction mechanisms of thick-film conductors and resistors. 

Pike, G.E. and Seager C.H., Electrical properties and conduction mechanism of Ru-based thick film resistors. Journal cf Applied Physics, 48(12), 5152-5169, December 1977. 

Tobita, T, Takasago, H., and Kariya, K., Investigation of conduction mechanism in thick film resistors trimmed by pulse voltage method, IEEE Transactions on CHMT, Vol. 15, No. 4, August 1992. 

Prudenziati, M. et al.. High Frequency Response and Conduction Mechanism in Thick Film (Cermet) Resistors, European Physical Societp Antwerp, Belgium, April 1980, pp. 399—407. 

G. E. Pike and C. H. Seager, Electrical properties and conduction mechanisms ofRu-based thick-film (cermet) resistors, J. Appl. Phys., Vol. 48, (1977), pp. 5152-68. 

It has been demonstrated that, by considering simple resistor microstructures and utilizing the multipath model, conduction mechanisms with very high activation energies (0.5 eV) can be used to explain the temperature dependence of resistors which exhibit very low activation energies. However, no single quantitative model developed thus far completely explains the conduction mechanism of thick-film resistors. 

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