The Zr-Si-N films were deposited using an unbalanced dc reactive magnetron sputtering of the alloyed ZrSi2 target in a mixture of argon and nitrogen onto steel and silicon substrates. This article reports on a systematic investigation of dependences of the structure, elemental composition, mechanical properties and oxidation resistance of Zr-Si-N films with a high (>= 25 at.%) Si content on the partial pressure of nitrogen p(N2), magnetron discharge current I-d, total sputtering gas pressure p(tau), substrate temperature T-s and dc and pulsed substrate bias U-s. It was demonstrated that (i) ZrSi2 films sputtered in (a) a pure argon (p(N2) = 0) and (b) Zr-Si-N films sputtered at very low values of p(N2) <= 0.03 Pa are crystalline, electrically conductive, optically opaque and exhibit a relatively high value of the microhardness H approximate to 17-20 GPa; (ii) Zr-Si-N films sputtered at p(N2)>= 0.1 Pa are X-ray amorphous, electrically insulating, optically transparent and exhibit (a) a high microhardness H of about 30 GPa and (b) a low compressive macrostress sigma of about -1.2 GPa; (iii) an increase in the substrate temperature T-s from 300 to 750 degrees C has no effect on the structure and H of as-deposited films; the structure of the Zr-Si-N film sputtered at T-s=750 degrees C remains X-ray amorphous and its hardness H does not decrease with increasing T-s, i.e. it is approximately the same (approximate to 30 GPa) as that of the film sputtered at T-s=500 degrees C; (iv) the Zr-Si-N films with high (>= 25 at.%) Si content and high H approximate to 30 GPa can be produced in the metallic mode of sputtering, i.e. they can be produced approximately four times faster than the binary nitrides such as, for instance, the TiN films-, and (v) the Zr-Si-N films with a high (>= 55 vol. %) content of the a-Si3N4 phase, composed of a mixture of a-Si3N4+ZrNx>1 phases, exhibit a high oxidation resistance in flowing air, greater than 1300 degrees C. (c) 2004 Elsevier B.V. All rights reserved.