Influence of post-deposition annealing on the microstructure and properties of Ga_2O_3:Mn thin films deposited by RF planar magnetron sputtering

摘要

Thin films of Ga_2O_3:Mn have been deposited on silicon (100) substrates without intentional heating by radio frequency (RF) planar magnetron sputtering from a Mn-doped Ga_2O_3 target in an oxygen-argon mixture atmosphere. Microstructure and properties of the deposited Ga_2O_3:Mn films were systematically investigated as a function of the post-deposition annealing temperature in the range between 500 ℃ and 1200 ℃. X-ray diffraction (XRD) measurements showed that the as-deposited Ga_2O_3:Mn films were of an amorphous structure in nature. The Ga_2O_3:Mn films became crystalline by the post-deposition annealing above 800 ℃ and the crystallinity of the films was continuously improved up to the annealing temperature of 1200 ℃. It was shown that the annealed Ga_2O_3:Mn films possessed a monoclinic β-Ga_2O_3 phase having a textured structure with (400) and (-401) crys-tallographic planes oriented preferentially parallel to the substrate surface. The lattice parameters of the monoclinic β-Ga_2O_3 phase in the 1200 ℃ annealed Ga_2O_3:Mn films were measured to be a = 12.152 A, b = 3.043 A, and c = 5.785 A.