Tantalum based multilayers for high temperature sensor applications

In this study, the impact of post deposition annealings performed at 500degC in air up to 12 h on the electrical performance and the microstructure of sputter-deposited tantalum (Ta) and tantalum nitride (TaN) thin films is investigated. Morphological investigations are done using techniques such as focused ion beam and X-ray diffraction. A multi-layered metallization is proposed consisting of a porous Ta start layer and a dense Ta mid layer. The TaN top film serves for passivation purposes. Compared to the ldquoas depositedrdquo state, the increase in sheet resistance of the three layered set-up is about 50% upon annealing for 12 h.