Increasing the deposition rate of oxide films by increasing the plasma reactivity

One of the major problems of reactive sputtering is the dramatically deposition rate decrease when the target surface is poisoned. For decades, numerous papers have been published in order to solve this problem using the same basic idea: prepare a compound film while the target remains non-poisoned. In this work, we propose an original way to reach this goal. From previous results, we have shown that the substrate oxidation occurs mainly by the reactive gas atomic species. In order to favour this reaction we have increased the plasma reactivity by a RF coil located between the DC magnetron target and the substrate. We have studied three reactive systems: Sn–Ar/O2, Ti–Ar/O2 and Ag–Ar/O2. For each of these systems, we have estimated the RF coil influence on the chemical behavior of both the discharge and the films. The discharge is characterized by mass spectrometry measurements whereas the filmsʹ compositions are obtained by XPS. Increasing the RF coil power, we observe an increase of the oxygen concentration in the films for the same introduced pO2. On the other hand, the target metal-compound transition, observed on the deposition rate measurements, is not influenced by the amplification. So, using the RF coil, the fully oxidized films is reached at lower reactive gas flow and consequently at higher deposition rate.