Influence of molybdenum bottom electrodes on crystal growth of aluminum nitride thin films

The authors have found that molybdenum (Mo) bottom electrodes strongly influence the crystal growth of aluminum nitride (AlN) thin films. AlN films were prepared on Si, Mo/Si and Mo/AlN-interlayer/Si substrates. The crystal orientation and microstructure of AlN films prepared on Si substrates strongly depend on sputtering pressure. On the other hand, the crystal orientation and microstructure of AlN films prepared on Mo/Si and Mo/AlN-interlayer/Si hardly depends on sputtering pressure. The local epitaxial growth of AlN films is observed in an almost random texture, and the crystal orientation of the Mo electrodes strongly influences that of the AlN films.