论文部分内容阅读
本文研究了低温GaN(LTGaN)缓冲层表面形貌,其随厚度的变化规律及对随后生长GaN外延膜各项性能的影响。用场发射扫描电镜(SEM)和原子力显微镜(AFM)研究LTGaN缓冲层表面形貌,发现随着厚度的增加,其表面由疏松、粗糙变得致密、平整,六角GaN小晶粒的数量减少,且取向较为一致。用X光双晶衍射(XRD)、AFM和Hall测量研究1μm厚本征GaN外延薄膜的结晶质量、表面粗糙度、背底载流子浓度和迁移率等性能,发现随着LTGaN缓冲层厚度的增加:XRD的半高宽FWHMs增大,表面粗糙度先减小后又略有增大,背底载流子浓度则随之减少,而迁移率的变化则不明显。通过分析进一步确认LTGaN缓冲层的最优生长时间。
In this paper, the surface morphology of low temperature GaN (LTGaN) buffer layer, its variation with thickness and its effect on the performance of GaN epitaxial films grown subsequently are studied. The surface morphology of the LTGaN buffer layer was investigated by field emission scanning electron microscopy (SEM) and atomic force microscopy (AFM). The surface morphology of the LTGaN buffer layer was found to be dense and smooth with increasing thickness, and the number of small hexagonal GaN grains decreased The orientation is more consistent. X-ray double crystal diffraction (XRD), AFM and Hall measurements were used to investigate the crystal quality, surface roughness, background carrier concentration and mobility of 1μm thick intrinsic GaN films. It was found that with the thickness of LTGaN buffer layer Increasing: The FWHMs of FWHM of XRD increases, the surface roughness decreases first and then increases slightly, while the background carrier concentration decreases, while the change of mobility is not obvious. The optimal growth time of the LTGaN buffer layer was further confirmed by analysis.