Stabilization of high-deposition-rate reactive magnetron sputtering of oxides by in situ spectroscopic ellipsometry and plasma diagnostics

A control system for stabilizing the reactive magnetron-sputter process is applied that is based on a combination of a short-term stabilization of the plasma and a long-term stabilization employing an in situ spectroscopic el lipsometer. For the formation of niobium pentoxide, a measurement of the re active gas partial pressure with a lambda-probe measurement was employed. I t turns out that the specific deposition rate, i.e,, deposition rate divide d by the power density, is a suitable control parameter. Compared to the ox ide model the deposition rate of niobium pentoxide films deposited in the t ransition mode could be enlarged by a factor of more than 4. The films were grown at different process parameters (oxygen partial pressure, target pow er, absolute pressure, midfrequency and de technique) onto unheated substra tes. In situ! spectroscopic ellipsometry and ex situ spectroscopic ellipsom etry at different angles of incidence and scanning electron microscopy inve stigations were applied to study the optical properties and the morphology of the films. (C) 2000 American Vacuum Society. [S0734-2101(00)07604-1].