射频磁控溅射Si过渡层对自支撑金刚石膜形核面的影响

Effect of RF sputtering transition layer Si on the nucleation surface of freestanding diamond film

采用射频磁控溅射法在镜面抛光单晶硅片表面制备Si过渡层,然后以甲烷和氢气为反应气体,采用热丝化学气相沉积法制备金刚石膜,去除基体Si和Si过渡层后,在自支撑金刚石膜的形核面上采用射频磁控溅射法沉积ZnO薄膜。通过X线衍射、Raman光谱分析、场发射扫描电镜和原子力显微镜等对膜层的表面形貌和微观结构进行测试与表征。结果表明:相对于无过渡层的样品,溅射Si过渡层能有效增加单晶硅基体表面金刚石的形核密度,降低金刚石膜形核面上非金刚石相的含量,提高金刚石膜的质量,所得金刚石自支撑膜的形核面更加光滑,表面粗糙度从6.2 nm降低到约3.2 nm,且凸起颗粒和凹坑等缺陷显著减少,在形核面上沉积的ZnO薄膜具有较高的c轴取向。

The freestanding diamond film was fabricated by hot-filament chemical vapor deposition technique. Before deposition, a transition layer of Si was sputtered on the polished p-type silicon substrate by RF（ratio frequency） magnetron sputtering technique. Then a ZnO thin film was deposited on the nucleation surface of as-deposited freestanding diamond. The surface morphology and microstructure of films were characterized by XRD, Raman spectrum, SEM and AFM（atomic force microscope）. The results reveal that the sputtered transition layer Si can enhance the nucleation density of diamond and reduce the non-diamond phase on the nucleation surface, thus improve the quality of diamond. Besides, the roughness of nucleation surface decreases from 6.2 nm to 3.2 nm with the help of sputtered Si layer. It also makes the nucleation surface smoother and cleaner and has fewer defects like heave and holes. ZnO grown on freestanding diamond＇s nucleation surface is highly c-axis oriented.