Minimizing residual stress of aluminum nitride (AlN) thin films using multi-step deposition of DC pulsed sputtering

Abstract

In this study, the minimum residual stress of aluminum nitride (AlN) thin films was obtained controllably using a multi-step deposition technique in a pulsed DC sputtering system. The link between film crystal orientation and residual stress received from X-ray diffraction (XRD) data analyses on this growing AlN experiment was investigated by the comparison of film stress characteristics between one-step deposition and multi-step deposition. The structure, thickness, crystalline status and residual stress of AlN thin films were measured using scanning electron microscope (SEM), atomic force microscope (AFM) and X-ray diffraction (XRD) respectively. The results reveal that, under the same processing duration, with various intervals of deposition, the AlN film has a distinct structure with various stress properties. It can be concluded from this experiment that the AlN film residual stress can be effectively reduced by multi-step deposition. In addition, we are aiming to examine the spectrum data acquired by optical emission spectroscopy (OES) in order to see whether there is any association with OES data, the crystalline state, and thin-film quality obtained by the measured result in this study. In our findings, OES data in conjunction with XRD analyses, it is convinced that this multi-step deposition approach can be used to determine the minimum residual stress of thin-film characteristics in AlN thin-film deposition.