多层式金刚石膜上沉积ZnO薄膜的研究

Research of ZnO Films Deposited on Multi-layer Diamond Substrates

提出了一种制作ZnO/金刚石/硅结构声表面波器件的新工艺。利用热丝化学气相沉积(HFCVD)技术,通过逐次调整气压、碳源浓度等生长参数,在硅基片上沉积了晶粒尺寸逐层减小的、光滑的多层式金刚石薄膜,表面粗糙度低于20 nm,厚度大于35μm。在金刚石膜上制作了线宽为8μm的IDT电极。尝试利用射频(RF)磁控溅射法在制备的多层式金刚石膜上生长ZnO薄膜,X-射线衍射(XRD)结果表明,当衬底温度(Th)为250℃、气压(P)为0.4 Pa时,在多层式金刚石薄膜衬底上可沉积高度c轴取向的ZnO薄膜,电阻率接近106Ω.cm,满足制作声表面波器件对衬底材料的要求。

In this paper, we propose a novel process of fabricating ZnO/diamond/Si multilayer surface acoustic wave（SAW） device. The multi-layer diamond films were prepared by hot filament chemical vapor deposition（HF- CVD）. The diamond grain size was reduced gradually by changing deposition parameters, such as pressure and carbon density. The surface roughness is less than 20 nm and the thickness is larger than 35μm. After that, IDT electrodes with the line width of 8 μm were formed on the surface of multi-layer diamond film. Then we deposited ZnO films on the multi-layer diamond substrates by RF magnetron sputtering to fabricate SAW device. X-ray diffraction （XRD） test results showed highly c-axis orientation of ZnO film was deposited on multi-layer diamond substrates, when Th=250 ℃ and P=0.4 Pa, the resistance ratio was -10^6 Ω· cm observed by I-V test, which satisfied the requirement of substrate materials for SAW device.