不同Mo层厚度的AlN/Mo/Sc_(0.2)Al_(0.8)N复合结构上MOCVD外延GaN

GaN Grown on Sputtered AlN/Mo/Sc_(0.2)Al_(0.8)N Composite Structure with Different Mo Thickness

采用脉冲直流磁控溅射法在Si(100)衬底上制备了AlN/Mo/Sc_(0.2)Al_(0.8)N复合结构薄膜,在该结构上通过金属有机化学气相沉积(MOCVD)技术进行GaN薄膜的外延。使用原子力显微镜、高分辨X射线衍射、粉末X射线衍射、扫描电子显微镜和拉曼光谱研究了Mo插入层的厚度对Sc_(0.2)Al_(0.8)N缓冲层和GaN外延层晶体质量的影响,研究了Sc_(0.2)Al_(0.8)N缓冲层对Mo上生长的GaN外延层的影响。研究结果表明,Mo插入层的厚度是影响Sc_(0.2)Al_(0.8)N缓冲层和GaN外延层的重要因素,Sc_(0.2)Al_(0.8)N缓冲层对Mo上GaN晶体质量的提高具有重要意义。随Mo厚度的增加,Sc_(0.2)Al_(0.8)N缓冲层的表面粗糙度先减小后增大,GaN外延层的(002)面X射线衍射摇摆曲线半峰全宽先减小后增大。当Mo插入层厚度为400 nm时,GaN外延层的晶体质量最好,GaN(002)面的X射线衍射摇摆曲线半峰全宽为0.51°,由拉曼光谱计算得到的压应力483.09 MPa;直接在Mo上进行GaN的外延,GaN(002)面的X射线衍射摇摆曲线半峰全宽无法测得,说明在Mo上进行GaN的外延需要Sc_(0.2)Al_(0.8)N缓冲层。

AlN/Mo/Sc_(0.2)Al_(0.8)N composite structure films were prepared on Si(100)substrate by pulsed DC magnetron sputtering,and the epitaxy of GaN films was grown by metal-organic chemical vapor deposition(MOCVD).Atomic force microscopy,high-resolution X-ray diffraction,powder X-ray diffraction,scanning electron microscopy and Raman spectroscopy were used to study the effect of the thickness of the Mo layer on the crystal quality of the Sc_(0.2)Al_(0.8)N layer and the GaN epitaxial layer,and the importance of the Sc_(0.2)Al_(0.8)N layer for the GaN epitaxial layer grown on Mo was also studied.The results show that the thickness of the Mo layer is an important factor affecting the Sc_(0.2)Al_(0.8)N layer and the GaN epitaxial layer,and the Sc_(0.2)Al_(0.8)N layer is of great significance to the epitaxy of GaN on Mo.When the thickness of the Mo layer is 400 nm,the crystal quality of the GaN epitaxial layer is the best,the full width at half maximum of the X-ray diffraction on the GaN(002)surface is 0.51°,and the compressive stress calculated by Raman spectroscopy is 483.09 MPa.