Study On The Properties Of Pretreated And Ion Implanted Gallium Nirtide

Gallium nitride materials have become one of the forefront research topics in semiconductor materials due to their excellent properties. In this paper, GaN films were grown on sapphire substrate by Metal Organic Chemical Vapor Deposition (MOCVD). The properties of GaN were studied. In addition, Fe-, Ni-doped GaN thin films have been made by ion implantation technology and the origin of ferromagnetism was discussed. The main results are as followings:1. The etching technology of the sapphire substrate has been studied. The results showed that the sapphire substrates with ideal graphic were obtained in the H3PO4 etch solution at 265?C for 45⁵0min.2. The properties of the GaN epilayer were analyzed by X-ray diffraction (XRD), Atomic force microscope (AFM) and Raman spectra in order to study the influence of the spphire substrate pretreated on the crystal quality of GaN film. These results showed that the GaN epilayer grown on the pretreated sapphire substrate exhibited excellent crystal quality, the XRD FWHMs of the GaN epilayer in (0002) plane and (10 2) plane were 293arcsec and 560arcsec, respectively; the dislocation density was reduced to 9.6×10⁶cm^-2; the residual stress was reduced to 0.071GPa.3. The effect of heat treatment on GaN epilayer was studied. The results showed that the quality of the GaN epilayer was improved by rapid thermal processor. The XRD FWHMs becomes narrow and the carrier concentration becomes larger. When the GaN epilayers were annealed at 950?C, the XRD FWHM of GaN (0002) plane is 301arcsec and the carrier concentration is up to 1×10¹⁸cm^-3.4. Fe^-, Ni-doped GaN films have been prepared by ion implantation and obviously room-temperature ferromagnetic behavior were obtained. The magnetic property of GaN samples was determined by the kind of ion, dose and annealing temperature. GaN epilayers with better lattice quality and ferromagnetic properties were obtained after being annealed at 800?C, when the dose of Fe ion with energy of 150keV was 1×10¹⁶cm^-2. In addition, the origin of ferromagnetism was discussed.