δ掺杂对Si衬底GaN蓝光LED外延膜性能的影响研究

用X射线衍射方法通过不同晶面的ω扫描测试,分析了Si衬底GaN蓝光LED外延膜中n-型层δ掺杂Si处理对外延膜结晶性能的影响。报道了Si衬底GaN外延膜系列晶面的半峰全宽(FWHM)值。通过使用晶格旋转(Lattice-rotation)模型拟合,计算出样品的螺位错密度和刃位错密度。结果表明,δ掺杂Si处理后生长出的样品螺位错密度增大、刃位错密度减小,总位错密度有所减小。通过对未经δ掺杂处理和δ掺杂处理的GaN外延膜相应ω-2θ扫描半峰全宽值的比较,发现δ掺杂Si处理后生长出的样品非均匀应变较大;相应样品的LED电致发光光谱I、-V特性曲线显示δ掺杂后样品性能变好。

Effect of δ-Doping on Performance of GaN Blue LED Epitaxial Films on Si Substrates

The effect of δ-doping in n-type layers on crystal performance of GaN epitaxial films on Si substrates was studied by ω-scan of different crystal planes with X-ray diffraction method. The full width at half maximum (FWHM) values of the serial crystal planes of the GaN epitaxial films on Si substrates were reported. By using the lattice-rotation model, the screw and edge dislocation densities of the samples were calculated. The results showed that the screw dislocation density increased, the edge dislocation density decreased, and the total dislocation density decreased in the δ-doped GaN films. By comparing the relevant FWHM values of ω-2θ scan of δ-doped and untreated samples, it was found that the inhomogeneous strain of GaN films increased by δ-doping. In addition, LED fabricated using the δ-doped samples showed better electroluminescence performance and I-V characteristic compared with that of the untreated samples.