S Tudy On Preparation And Characterization S Of Transition Metal-Doped AlN Thin Films

Diluted magnetic semiconductors (DMSs) attract many researchers’ interests due to its potential applications in spintronic devices, but the magnetic source of DMSs has always been the focus of debate. Thus it is quite necessary to further study for proving magnetic source. The A1N film is a III-V semiconductor compound with direct gap and wide band gap and has good photoelectric properties. Therefore, the study on the transition metal-doped AlN films has great significance for theory development and practical application.In this paper, using radio frequence (RF) and direct current (DC) magnetron co-sputtering method, transition metal-doped AlN films were deposited on Si (100) substrates by controlling the experimental parameters, such as working pressure, working current, etc. The preferred orientation and crystallinity of AlN films was characterized by X-ray diffraction (XRD) and Raman spectrum. At first, AlN film samples with (100) preferred orientation were obtained. Then they were doped with non-magnetic transition metal Ti and Zn, and magnetic transition metal Fe and Mn. Later, the preferred growth orientations of Ti-and Fe-doped AlN film samples on (100) direction and Zn-and Mn-doped AlN film samples on (002) direction were found. Two peaks of Mn were observed in XRD spectra of Mn-doped AlN film samples, it was shown that Mn has been incompletely doped into the crystal lattice of AIN.The surface morphology of Ti-and Zn-doped AlN films was described by scanning electron microscope (SEM). It was observed that the surface structure of the film was very compact and had a good uniformity, which means that the film with good crystallinity was obtained. In the experiment, the atomic concentration of Zn-doped AIN films was measured. The atomic concentration of Zn decreased with the increase of the sputtering current of Zn target.The magnetism of Mn-and Fe-doped AIN films were measured by vibrating sample magnetometer (VSM) at room temperature. Due to the incompletely doping of Mn into crystal lattice, Mn-doped AIN films appeared to be paramagnetism. Fe-doped AIN films expressed ferromagnetism, and the saturation magnetization was about5.85×10-6emu/g and the coercive field was about0.198koe for the Fe-doped AIN film deposited at the sputtering current of0.4A.