【摘要】 利用金属有机化学汽相沉积(MOCVD)法在硅衬底上生长具有AlN插入层的GaN外延膜,采用高分辨X射线衍射(HRXRD)和卢瑟福背散射/沟道(RBS/Channeling)技术研究分析其结构和应变性质。从RBS<0001>沟道谱可知,该外延膜具有良好的结晶品质,χmin=2.5%。利用不同方位角上XRD摇摆曲线测量,可得出GaN(0001)面与Si(111)面之间的夹角β=1.379°。通过对GaN(0002)和GaN(101-5)衍射面的θ-2θ扫描,可以得出GaN外延膜在垂直方向和水平方向的平均弹性应变分别为-0.10%±0.02%和0.69%±0.09%。通过对{101-0}面内非对称<12-13>轴RBS角扫描可得出由弹性应变引起的四方畸变eT在近表面处为0.35%±0.02%。外延膜弹性性质表明GaN膜在水平方向具有张应力(e∥>0)、在垂直方向具有压应力(e⊥<0),印证了XRD的结果。四方畸变是深度敏感的,通过对不同深度的四方畸变计算可知,AlN插入层下面的GaN外延膜弹性应变释放速度比AlN层上面的GaN层弹性应变释放快,说明AlN层的插入缓解了应变释放速度。更多还原

【Abstract】 A hexagonal GaN layer with a LT-AlN（low temperature） interlayer grown on Si（111） by metal-organic chemical vapour deposition（MOCVD） method was characterized by high resolution X-ray diffraction（HRXRD） and Rutherford backscattering（RBS）/channeling.The crystal quality of the film is perfect with a χ_<sub>min=2.5%.（According） to the results of XRD ω-scan,the angle between the GaN（0001） plane and the Si（111） plane was determined.The elastic strains in the perpendicular and parallel directions were calculated to be-0.10%±0.02% and 0.69%±0.09% respectively by θ-2θ scan of GaN（0002） and GaN（101-5） diffractions.By the angular scan around an off-normal <12-13> axis in the {101-0} plane of the GaN layer,the tetragonal distortion e_T,which is caused by the elastic strain,was determined to be 0.35%±0.02% near the surface,indicating a tensile strain in the parallel direction(e^//>0) which results in a compressive strain in the perpendicular direction（e^⊥<0） due to the elastic properties of the epilayer.This result coincides with that from XRD perfectly.The elastic strain of the GaN epilayer under the AlN interlayer releases more quickly than which upon the AlN interlayer with the thickness increasing.更多还原