The influence of deposition rate on the stress and microstructure of AlN films deposited from a filtered cathodic vacuum arc

Abstract

Aluminium nitride (AlN) thin films have been reactively deposited using a filtered cathodic vacuum arc system. A pulsed substrate bias was applied in order to increase the average energy of the depositing species. The stress and microstructure of the films were determined as a function of the deposition rate and pulse bias amplitude/frequency. The stress generated in films grown with high voltage pulsed bias depended on the deposition rate and a transition from tensile stress to compressive stress occurred as the deposition rate increased. This trend was accompanied by progressive changes in the microstructure. In order of increasing deposition rate, the films exhibited: a porous structure with tensile stress; a dense AlN film with compressive stress; and a dense AlN film showing evidence of a thermally induced reduction in stress.