后退火对射频磁控溅射法制备Mg掺杂Ga2O3薄膜性质的影响

Effect of post-annealing on Mg doped Ga2O3 films deposited by RF magnetron sputtering

本文采用双靶材交替溅射的射频磁控溅射法生长了高质量的Mg掺杂氧化镓薄膜,并将制备的样品在1000℃条件下进行后退火处理,以研究退火前后Mg掺杂Ga2O3薄膜的性质变化。XRD结果表明,退火后的(004)、(202)和(120)峰从无到有,(401)、(601)和(122)峰由强变弱,表明退火改变了Mg掺杂Ga2O3薄膜的结构。AFM结果表明,退火后的薄膜表面均方根粗糙度由1.3637nm增大到17.1133nm。EDS结果表明,退火处理后的Mg元素重量百分比有所提高。紫外可见透射光谱研究表明,退火前薄膜在200-1500nm波长范围内的平均光透过率较低,大约为80%,退火后平均光透过率明显提高到90%以上,此外薄膜光学吸收边蓝移,带隙宽度变大,表明退火有助于改善薄膜结构,增强光透性。光致发光谱实验结果表明,相比较退火处理后的薄膜,退火前的光致发光峰几乎可以忽略不计,这说明退火可显著改变Mg掺杂Ga2O3薄膜的光致发光特性。

In this paper, high-quality Mg doped gallium oxide films were grown by Radio frequency magnetron sputtering(RF magnetron sputtering) with double target alternating sputtering. The as-prepared samples were annealed at 1000 C to explore the properties of Mg-doped Ga2O3 films before and after annealing. The XRD results show that the peaks of(004),(202) and(120)appear after annealing, and the peaks of(401),(601) and(122) become stronger. It is shown that post annealing can change the structure of Mg doped Ga2O3 thin films. After annealing, the AFM results show that the surface RMS roughness of the films increases from 1.36 nm to 17.11 nm. The EDS results show that the weight percentage of Mg is increased after annealing. UV-visible transmission spectroscopy studies show that, after annealing, the average light transmittance of Mg doped Ga2O3 at the wavelength range of 200-1500 nm reaches to 90% from 80%, the optical absorption edge of the film is blue-shifted and the band gap width becomes large, indicating that the annealing is helpful to improve the film structure and enhance light transmittance.From the photoluminescence spectra, we can see the photoluminescence peaks before annealing are almost negligible compared with that of the annealed films, which indicates that the annealing can significantly change the photoluminescence properties of Mg-doped Ga2O3 films.