为获得高质量的β-Ga2O3薄膜, 将c面蓝宝石上生长的GaN薄膜进行高温氧化制成了Ga2O3/GaN/蓝宝石模板, 进而在模板上利用金属有机化学气相沉积(MOCVD)工艺进行了β-Ga2O3薄膜的同质外延。通过X射线衍射仪、原子力显微镜、场发射扫描电子显微镜等方法对样品的晶体结构、表面形貌等性质进行测试与分析。结果表明, 该方法获得的β-Ga2O3薄膜晶体质量受GaN薄膜氧化效果与MOCVD工艺条件等因素影响较大。通过优化实验条件, 得到了质量较高的β-Ga2O3薄膜。与蓝宝石上或GaN薄膜上异质外延得到的β-Ga2O3薄膜相比, 薄膜的晶体质量明显提高。通过对比不同样品的晶体质量、表面形貌和制备过程, 发现该方法成功地将β-Ga2O3薄膜在蓝宝石衬底或GaN/蓝宝石模板上异质外延转化为了Ga2O3/GaN/蓝宝石模板上的同质外延, 有效地减小了β-Ga2O3薄膜和蓝宝石、GaN之间较大的晶格失配和热失配, 有利于提高β-Ga2O3薄膜的晶体质量。

To obtain high-quality β-Ga2O3 thin film, GaN thin film grown on c-plane sapphire is made into Ga2O3/GaN/sapphire template by thermal oxidation, and the β-Ga2O3 thin film is grown on the template by metal-organic chemical vapor deposition(MOCVD). The crystal structure and surface morphology of the samples are measured and analyzed by X-ray diffraction, atomic force microscope and field emission scanning electron microscope. The results show that the crystal quality of the β-Ga2O3 films is affected by GaN film oxidation effect and MOCVD process conditions greatly. By optimizing the experimental conditions, the high-quality β-Ga2O3 thin films are obtained. By comparing with the films grown on sapphire or GaN films, the crystal quality of the β-Ga2O3 films is found improved obviously. We find that this method successfully transforms the heteroepitaxy of the β-Ga2O3 film on sapphire substrate or GaN/sapphire template into the homoepitaxy of that on Ga2O3/GaN/sapphire template, effectively reduces the large lattice mismatch and thermal mismatch between β-Ga2O3 film, sapphire and GaN, and is beneficial to improve the crystal quality of β-Ga2O3 film.