GAS-PRESSURE DEPENDENCE OF ALN FILM PROPERTIES IN ALTERNATING SPUTTERING SYSTEM

AlN films were prepared in N-2 and N-2/Ar gas by the alternating DC sp uttering method wherein two Al targets facing each other were sputtere d alternately, and the mechanism of film damage in AlN film preparatio n was investigated. When the gas pressure was lower than 3 mTorr, the crystalline orientation of the film inclined slightly toward the direc tion of incidence of depositing atoms. In this system, the influence o f plasma exposure on the film properties was decreased. This was due t o the decrease of electron Bow into the substrate. Degradation of the c-axis orientation was ascribed to both the tilt of the growth directi on of the (00 . 2) plane at low gas pressures and film bombardment by positive ions with energies above 60 eV.