GaN缓冲层对直流反应磁控溅射AlN薄膜的影响

摘要

通过直流磁控反应溅射制备了氮化铝(AlN)薄膜,研究了沉积条件与氮化镓(GaN)缓冲层对薄膜质量的影响.利用X-射线衍射仪(XRD)和扫描电镜(SEM)表征了AlN薄膜的晶体结构和表面形貌.XRD研究结果表明,低工作压强、短靶距和适当的氮气偏压有利于(002)择优取向的AlN薄膜沉积.随着沉积时间的增加,沉积在50 nm厚的GaN缓冲层上的AlN薄膜的(002)面的衍射峰的半高宽急剧减小,而沉积在1-μm厚的GaN薄膜上的AlN薄膜的(002)面的衍射峰的半高宽几乎不变.SEM测试结果表明:在沉积的初期,沉积在1μm厚的GaN薄膜上的AlN薄膜的(002)面的晶粒大小分布比沉积在50 nm厚的GaN缓冲层上的AlN薄膜的均匀,而随着沉积时间的增加,它们的晶粒大小分布几乎趋向一致.%Abstract:AlN films were prepared by DC reactive magnetron sputtering,and the effects of deposition conditions and GaN buffer layers on their qualities were also investigated.The crystal structure and surface morphology of films were characterized by X-ray diffractometer (XRD) and scanning electron microscopy (SEM).The XRD results show that low pressure,short target-to-substrate distance and appropriate N2 partial pressure can facilitate the (002) preferential orientation AlN films.With the increase of deposition time the full width half maximum of (002) diffraction peak for the films deposited on 50-nm-thick GaN buffer layers decreases drastically,but it was nearly unchanged for AlN films deposited on 1-μm-thick GaN films.The SEM measurements reveal that the grain size distribution of AlN film deposited on 1-μm-thick GaN films is much uniformer than on 50-nm-thick GaN buffer layers in the early stages of deposition,and with the increase of deposition time their grain size distributions can nearly reach the same.