InP衬底上InAlAs异变缓冲层和高铟组分InGaAs的生长温度优化

利用气态源分子束外延技术在InP衬底上生长了包含InAlAs异变缓冲层的In0.83Ga0.17As外延层.使用不同生长温度方案生长的高铟InGaAs和InAlAs异变缓冲层的特性分别通过高分辨X射线衍射倒易空间图、原子力显微镜、光致发光和霍尔等测量手段进行了表征.结果表明, InAlAs异变缓冲层的生长温度越低, X射线衍射倒易空间图 (004) 反射面沿Qx方向的衍射峰半峰宽就越宽, 外延层和衬底之间的倾角就越大, 同时样品表面粗糙度越高.这意味着材料的缺陷增加, 弛豫不充分.对于生长在具有相同生长温度的InAlAs异变缓冲层上的In0.83Ga0.17As外延层, 采用较高的生长温度时, X射线衍射倒易空间图 (004) 反射面沿Qx方向的衍射峰半峰宽较小, 77K下有更强的光致发光, 但是表面粗糙度会有所增加.这说明生长温度提高后, 材料中的缺陷得到抑制.

Optimization of growth temperatures for InAlAs metamorphic buffers and high indium InGaAs on InP substrate

In0.83Ga0.17As layers were grown on InP substrate with InAlAs metamorphic buffers by gas source molecular beam epitaxy.The characteristics of In GaAs and InAlAs layers grown with different temperature schemes were investigated by high resolution X-ray diffraction reciprocal space maps, atomic force microscopy, photoluminescence and Hall-effect measurements.Results showthat a higher growth temperature gradient of the InAlAs metamorphic buffers leads to a broader (004) reflection peak.The tilt angle between the epilayer and the substrate increases as well.The surface of the buffer layer becomes rougher.It indicates that the material defects increase and lattice relaxation becomes insufficient.In0.83Ga0.17As layers were grown on the InAlAs metamorphic buffer with a fixed growth temperature gradient.A higher growth temperature leads to a moderate full width at half maximum along the Qxdirection of the (004) reflection, a stronger photoluminescence at 77 K, but a rougher surface of In0.83Ga0.17As.This indicates that the material defects can be suppressed at higher growth temperatures.