Resistive overlayer for thin film devices

摘要

A thin film, solid state device includes a conductive thin film formed on a substrate, with a resistive layer overlying the conductive thin film and with electrical contacts formed on the upper surface of the resistive layer. Electrical current flows between the electrical contacts through the resistive overlayer and the conductive thin film. The resistivity and dimensions of the resistive layer are such that, preferably, only a small fraction of any current flowing between the electrical contacts will flow solely within the resistive layer, yet the magnitude of the current will not be reduced below a desired signal level due to the presence of the resistive layer. The resistive layer is comprised of material which will not diffuse into the thin film conductive layer during device processing. Nitrogen doped tantalum is the preferred material for the resistive layer. A compound or mixture of a metal and either nitrogen or oxygen, where the compound or mixture will not diffuse into the thin film conductive layer, is also a useful material for the resistive layer.