中文摘要：

利用高分辨X射线衍射（HRXRD）与拉曼散射光谱（Ramanscatteringspectra）研究了氮化处理与低温AlN缓冲层对低压金属有机化学气相沉积（LP—MOCVD）在r面蓝宝石衬底上外延的a面GaN薄膜中的残余应变的影响。实验结果表明：与氮化处理后生长的a-GaN相比，使用低温AlN缓冲层后生长的。GaN具有较小的摇摆曲线的半高宽和较低的残余应变，而且其结构各向异性和残余应变各向异性也均有一定程度的降低。因此，与氮化处理相比，低温AlN缓冲层更有利于a-GaN的生长。

英文摘要：

The effect of nitridation treatment and the low temperature （LT） AlN buffer on structure and strain of a-plane GaN epilayers grown on r-plane sapphire by low pressure metalorganic chemical vapor deposition （LP-MOCVD） has been investigated by high resolution X-ray diffraction （HRXRD） and polarized Raman scattering spectra in backscattering configurations. For the sample using the LT-AlN buffer, the full widths at half maximum （FWHM） of X-ray rocking curves （XRC） and the strain of a-plane GaN are lower comparing with that of the sample with nitridation, which is consistent with the smaller in-plane stress anisotropic distribution in a-plane GaN epilayers with LT- AlN buffer.