Effect of nitrogen gas pressure on residual stress in AlN films deposited by the planar magnetron sputtering system

The crystal orientation and residual stress development in AlN films deposited on borosilicate (BLC) glass substrates were investigated by X-ray diffraction. Deposition was performed using two kinds of planar magnetron sputtering system: a conventional system (CPM system) and a special system with two facing targets (FTPM system). The nitrogen gas pressure (P-N) was varied over a suitable range for each system. The diffraction patterns of the AlN films showed that the c-axis orientation was improved when the films were deposited using the CPM system at a nitrogen gas pressure lower than 1 Pa. For the CPM system, compressive residual stress was found in films deposited at P-N less than or equal to 2 Pa and tensile residual stress at P-N>2 Pa. For the FTPM system, tensile residual stress was found in films deposited at P-N less than or equal to 0.8 Pa and compressive residual stress at P-N>0.8 Pa.