Pradeep Waduge

Macom Technology Solutions
  • Thermal Stability, Uniformity and Electrical Properties of Sputtered and Evaporated NiCr Thin Film Resistors

    Peter Ersland, Macom Technology Solutions
    Pradeep Waduge, Macom Technology Solutions
    Maik Katko, Macom Technology Solutions
    Lisza Elliot, MACOM

    NiCr is one of the most commonly used resistive materials for fabricating precision thin film resistors due to its wide range of resistivity, low temperature coefficient of resistivity (TCR), and high stability of electrical properties. NiCr thin film resistors are usually manufactured by evaporation or sputtering. It is well known that thermal evaporation of NiCr from a finite mass of molten alloy causes a film composition change away from the composition of the source, as well as film composition changes from run to run. Some electrical properties of NiCr thin film resistors strongly depend on the film microstructure (i.e. Ni:Cr ratio) in addition to its spatial geometry (film thickness) and the deposition parameters in the evaporator. As a result, while film thickness and deposition parameters are well controlled, often time resistivity of evaporated NiCr thin film resistors goes out of spec. Therefore, in this paper we are investigating the possibility of replacing the evaporated NiCr thin films with the sputtered NiCr thin films as resistors. Here, we present a comprehensive study of NiCr thin film resistors developed using DC sputtering system and discuss the effects of sputtering process parameters and substrate conditions on film microstructure, TCR and electrical properties.

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