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在蓝宝石(Al2O3)衬底上应用脉冲激光沉积技术(PLD)生长不同厚度的AlN缓冲层后进行GaN薄膜外延生长。采用高分辨X射线衍射仪(HRXRD)和扫描电子显微镜(SEM)对外延生长所得GaN薄膜的晶体质量和表面形貌进行了表征。测试结果表明:相比直接在Al2O3衬底上生长的GaN薄膜,通过生长AlN缓冲层的GaN薄膜虽然晶体质量较差,但表面较平整;而且随着AlN缓冲层厚度的增加,GaN薄膜的晶体质量和表面平整度均逐渐提高。可见,AlN缓冲层厚度对在Al2O3衬底上外延生长GaN薄膜的晶体质量和表面形貌有着重要的影响。
GaN thin films were epitaxially grown on AlGaN (Al 2 O 3) substrates by pulsed laser deposition (PLD) with different thickness of AlN buffer layer. The crystal quality and surface morphology of GaN films grown by epitaxial growth were characterized by high resolution X-ray diffraction (HRXRD) and scanning electron microscopy (SEM). The results show that the GaN thin films grown on the AlN buffer layer are more planar than those grown on the Al 2 O 3 substrate. However, with the increase of the AlN buffer layer thickness, the GaN thin films Quality and surface roughness are gradually increased. It can be seen that the thickness of the AlN buffer layer has an important influence on the crystal quality and the surface topography of the epitaxial growth of the GaN film on the Al2O3 substrate.