Fabrication of Nb2O5/SiO2 mixed oxides by reactive magnetron co-sputtering

Kęstutis Juškevičius, Martynas Audronis, Andrius Subačius, Simonas Kičas, Tomas Tolenis, Rytis Buzelis, Ramutis Drazdys, Mindaugas Gaspariunas, Vitalij Kovalevskij, Allan Matthews, Adrian Leyland

Research output: Contribution to journalArticlepeer-review


This paper investigates niobia/silica mixed oxide thin films deposited by reactive pulse-DC/RF magnetron co-sputtering of Nb and Si metal targets at room temperature. The reactive gas flow during the sputtering processes was either controlled by direct mass flow rate (i.e. constant reactive gas flow) or by an active feedback process control system. 61% and 137% higher deposition rates of Nb2O5 and SiO2 layers, respectively, were obtained using the latter technique as compared to constant reactive gas flow. Films exhibited bulk or near-bulk density. All mixture films produced in this study had an amorphous structure. A volume law of mixtures was used to determine the coating composition. It is shown that the fraction of SiO2 or/and Nb2O5 has a linear dependency on sputter target power density. On this basis, rugate filter coating designs can be easily deposited, where refractive index gradually varies between that of pure Nb2O5 and pure SiO2. Substantially less inhomogeneity of coating mixtures was found in films produced using a reactive sputtering process with feedback-control.

Original languageEnglish
Pages (from-to)95-104
Number of pages10
JournalThin Solid Films
Publication statusPublished - 1 Jan 2015


  • Niobia/silica mixtures
  • Reactive magnetron sputtering
  • Thin films


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