Siemens Aktiengesellschaft

Manfred Roschy

Alois Schauer

Wilfried Juergens

A thin-film circuit which includes temperature-compensated RC elements consisting of an AlTa alloy layer having approximately 3-17 at % tantalum in aluminum, which is sputtered or vapor deposited onto a non-conductive substrate, is produced by a process in which the AlTa alloy layer is deposited in an operative, reactive gas mixture, containing at least one of the gases O.sub.2, CO.sub.2, and N.sub.2 and the TC.sub.R value is established by the tantalum component of the alloy layer and/or partial pressure of the reactive gas, and the TC.sub.C value of the capacitors formed from the AlTa alloy layer is established by tempering to be at least approximately oppositely equal to the TC.sub.R value.

Process for the production of a thin-film circuit

Al-Ta alloy films containing 2 to 20 atomic % of Ta in Al exhibit an improved temperature stability. An Al-alloy film containing 7 atomic % of Ta has a resistivity of 60.mu..OMEGA. cm, a temperature coefficient of resistance of +100 ppm.degree./K and a sparking potential of about 400 V when anodizing in 0.1% H.sub.3 PO.sub.4. An Al-alloy film containing 15 atomic % of Ta has a specific resistance of 200.mu..OMEGA. cm, a temperature coefficient of resistance of -100 ppm.degree./K and a sparking potential of about 300 V when anodizing in 0.1% H.sub.3 PO.sub.4. The alloy films are applied on a non-conductive substrate, as by RF-cathode sputtering in a desired thickness and are useful for thin-film circuits, discrete resistors, capacitors, etc.

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Munich, Germany

Manfred Roschy