Integrated thin film resistor arrays for electronic implants based on microcrystalline silicon carbide

Phosphorus doped silicon carbide thin films are produced by plasma enhanced chemical vapor deposition (PECVD) to be used for integrated resistor arrays applied in electronic implants for electrotherapy. A DC magnetron sputtered aluminum film serves as the metallization layer. Depending on the deposition and annealing parameters the electrical properties of the amorphous or microcrystalline films can be varied over several orders of magnitude. With regard to the tolerable temperature coefficient (TCR) of 500 ppm/K the maximum sheet resistance (R/sub s/) is 2 k/spl Omega//sub /spl square// up to now. The patterning of the silicon carbide/aluminum system is done by a conventional 5 /spl mu/m-lithography and etch process resulting in an integration density of 40 M/spl Omega//mm/sup 2/. The applied thin film techniques prove to be more reliable and reproducible than the thick film processes used so far.