Synthesis of c-axis oriented AlN thin films at room temperature

Abstract

In this study, aluminium nitride (AlN) thin films were synthesised by plasma-enhanced reactive DC magnetron sputtering on glass and Si (100) substrates and the effect of bias voltages on the structural, optical and morphological properties of the coatings has been studied. According to the grazing angle XRD studies, AlN in hexagonal (wurtzite) structure has been obtained for all the coatings. (002) plane c-axis oriented films have been achieved at 150 and 175 V bias voltages. AFM analyses demonstrated that with the increase in the bias voltages, a transformation from coarse to fine granular morphology has been occurred and smoother surfaces with a decrease in the surface roughness from 3.40 nm to about 1.90 nm were obtained. The results also demonstrated that the high transmittance values of AlN films were not affected by the change in the bias voltages and about 80% of transmittance obtained for all AlN films deposited in this study.

Keywords:

• c-axis oriented AlN thin films
• Plasma-enhanced DC magnetron sputtering
• Bias voltage
• Surface morphology
• Microstructure
• Crystallinity
• Optical properties
• Transmittance