Eur. Phys. J. D 41, 303-309 (2007)
https://doi.org/10.1140/epjd/e2006-00218-8

Characterization of the ion cathode fall region in relation to the growth rate in plasma sputter deposition

Surfaces, Interfaces and Devices, Department of Physics & Astronomy, Utrecht University, P.O. Box 80, 3508TA Utrecht, The Netherlands

Corresponding author: ^a a.palmeroacebedo@phys.uu.nl

Received: 19 May 2006
Published online: 27 September 2006

Abstract

In plasma-assisted magnetron sputtering, the ion cathode fall region is the part of the plasma where the DC electric field and ion current evolve from zero to their maximum values at the cathode. These quantities are straightforwardly related to the deposition rate of the sputtered material. In this work we derive simple relations for the measurable axially averaged values of the ion density and the ion current at the ion cathode fall region and relate them with the deposition rate. These relations have been tested experimentally in the case of an argon plasma in a magnetron sputtering system devoted to depositing amorphous silicon. Using a movable Langmuir probe, the profiles of the plasma potential and ion density were measured along an axis perpendicularly to the cathode and in front of the so-called race-track. The deposition rate of silicon, under different conditions of pressure and input power, has been found to compare well with those determined with the relations derived.