Electrical Properties of Amorphous Rh Oxide Thin Films Prepared by Reactive Sputtering

Abstract

Conducting Rh oxide thin films were prepared by sputtering a Rh target in an Ar and O 2 mixed gas. Effects of the oxygen gas flow ratio on the crystallinity, chemical bonding state and resistivity were studied. Amorphous Rh 2 O 3 films were prepared at an O 2 flow ratio of 20%. The Rh 2 O 3 films had a relatively high resistivity of 2 mΩcm and a negative temperature coefficient of resistance (TCR) of -1000 ppm/°C, which indicated semiconducting characteristics. On the other hand, amorphous RhO x films with a composition of 1.5 ≤ x ≤1.7 were prepared at O 2 flow ratios above 40%. Resistivity of these RhO x films were 800 µΩcm and had almost no temperature dependence. Metallic conduction characteristics of RhO 2 were assumed to be revealed by the decrease in the oxygen deficiency.