Si(111)衬底上生长有多缓冲层的六方GaN晶格常数计算和应变分析

利用卢瑟福背散射/沟道技术和高分辨率X射线衍射技术对在Si(111)衬底上利用金属有机化合物气相外延技术(MOVPE)生长有多缓冲层的六方GaN外延膜进行结晶品质计算、晶格常数计算和应变分析. 实验结果表明：GaN外延膜的结晶品质为χ_min=1.54%，已达到完美晶体的结晶品质(χ_min=1%—2%)；GaN外延膜的水平方向和垂直方向晶格常数分别为：a_epi＝0.31903nm，c_epi=0.51837nm，基本达到G 关键词： GaN 高分辨X射线衍射 卢瑟福背散射/沟道 弹性应变

Characterization of crystal lattice constant and strain of GaN epilayers with different AlxGa1- xN and AlN buffer layers grown on Si(111)

Hexagonal GaN epilayers with different Al_xGa_1-xN and AlN buffer layers were grown on Si(111) by metal-organic vapor phase epitaxy (MOVPE). Under the same growth conditions, the sample with four Al_xGa_1-xN buffer layers and one AlN buffer layer were grown on Si(111). According to the results of Rutherford backscattering (RBS)/channeling along <0001> axis, the conventional θ—2θ scans normal to GaN(0002) and (1122) plane at 0° and 180° azimuthal angles, and the reciprocal-space X-ray mapping (RSM) on GaN(1015) plane, we obtained that the crystal quality of the GaN epilayer is perfect with χ_min＝1.54%. The crystal lattice constant of AlN, Al_xGa_1-xN and GaN epilayer has been calculated accurately, the lattice constant of GaN epilayer is almost equal to the theoretic data (a_epi=0.31903nm, c_epi=0.51837nm). The tetragonal distortion along the depth can got clearly from elastic strains of each layer in the normal and parallel directions, and the tetragonal distortion of GaN epilayer is nearly fully relaxed(e_T=0).