Growth of highly c-axis-oriented aluminum nitride thin films on molybdenum electrodes using aluminum nitride interlayers

Highly c-axis-oriented aluminum nitride (AlN) thin films have been prepared on molybdenum (Mo) electrodes by using AlN interlayers. AlN interlayers were prepared between the Mo electrodes and silicon substrates, such as AlN/Mo/AlN/SiO2/Si. The crystallinity and crystal orientation of the AlN films and Mo electrodes strongly depend on the thickness of the AlN interlayers. Although the sputtering conditions were the same, the full-width at half-maximum of the X-ray rocking curves of the AlN films decreased from 9.1° to 2.5° by using the AlN interlayer with a thickness of 200 nm. Furthermore, the interlayers drastically changed the morphologies of the AlN films by affecting the grain growth patterns.