Korean Journal of Materials Research ISSN:1225-0562(Print) 2287-7258(Online) 한국재료학회지

AlN thin film is highly valued for use as a high-temperature material because of its excellent heat resistance, thermal conductivity and high mechanical strength. In addition, it is known as a replacement material for ZnO, because it can be applied to surface acoustic wave elements and high-frequency filters using piezoelectric properties or sound velocity. In this study, an alternating sputtering method was used to fabricate an AlN thin film with excellent film quality. The c-axis orientation and residual stress of the fabricated AlN thin film were measured using an X-ray diffraction method. Nitrogen gas pressure and target electrode conversion time are important deposition conditions when producing a thin film using the alternating sputtering method. The AlN thin film fabricated on the glass substrate using the alternating planar magnetron sputtering method exhibited a crystal structure in which the c-axis was preferentially oriented in the normal direction of the substrate surface. The c-axis orientation was better when the target electrode switching time was short under the condition of low nitrogen gas pressure. Residual stress is tensile stress in the very low nitrogen gas pressure range (P_N ≤ 0.3 Pa), compressive stress in the low nitrogen gas pressure range (0.3 < P_N < 0.9 Pa), and in the high nitrogen gas pressure range (P_N ≥ 0.9 Pa), it becomes tensile stress. Residual stress shows tensile stress when the switching time is short, tensile stress decreases as the switching time increases, and becomes compressive stress when the switching time is sufficiently long (300 to 600 s). Compared to the simultaneous sputtering of two targets, the use of the alternating sputtering method can produce a high-quality thin film with excellent c-axis orientation and low residual stress.