金刚石基底上制备(002)AlN薄膜的研究

Research on preparation of(002)AlN thin film on diamond substrate

首先采用微波等离子体化学气相沉积(MPCVD)方法,在O2/H2/CH4混合气体气氛下利用大功率微波在(100)Si片上生长出了异质外延金刚石膜,X-射线衍射(XRD)、拉曼光谱和场发射扫描电子显微镜(FESEM)对薄膜的表征分析结果表明,制备的金刚石膜具有很高的金刚石相纯度,且晶粒排列紧密;继而采用射频磁控反应溅射法,在抛光的金刚石基底上成功制备了高C轴择优取向的氮化铝(AlN)薄膜,研究了不同的溅射气压、靶基距对AlN薄膜制备的影响,XRD检测结果表明,溅射气压低,靶基距短,有利于AlN(002)面择优取向,相反则更有利于AlN薄膜的(103)面和(102)面择优取向;研究了AlN薄膜在以N终止的金刚石基底和纯净金刚石基底两种表面状态上的生长机制,结果发现,以N终止的金刚石基底非常有利于AlN(002)面择优取向生长;从Al-N化学键的形成以及溅射粒子平均自由程的角度,探讨了其对AlN薄膜择优取向的影响。

The heterogeneous extended diamond films have been deposited on（100） silicon in O2/H2/CH4 mixture atmosphere by microwave plasma chemical vapor deposition（MPCVD）method.We characterize the structure and morphology of diamond films by X-ray diffraction（XRD）,Raman spectrometer and field emission scanning electron microscopy（FESEM）.The results show that the prepared diamond films have high diamond phase purity and closely arranged grains.AlN thin films with highly C-axis preferential orientation are deposited on polished diamond substrates by RF magnetron sputtering.The influence of sputtering pressure and target-substrate distance on the AlN film preparation has been studied.X-ray diffraction（XRD） tests show that the AlN（002） preferential orientation easily forms at low sputtering pressure and short target-substrate distance,while it is more favorible to the AlN thin films with preferential orientations（103） and（102） under contrary conditions.The growth mechanisms of AlN thin films on different surfaces of diamond substrate are studied.It is found that AlN thin films deposited on nitrogen-terminated diamond substates have AlN（002） preferential oritentation.The influence of the formation of Al-N chemical bond and the mean free path of sputtering particles on the preferential orientation of AlN thin films is also discussed.