脉冲偏压占空比对多孔氧化硅薄膜性质的影响

采用由脉冲负偏压调节的等离子体增强化学气相沉积方法，以硅烷为源气体，在玻璃基片上沉积得到了多孔二氧化硅薄膜。将反应过程中加在沉积区域的脉冲偏压固定在-350V，当占空比从0.162增大到0.864时，薄膜样品的形貌、成份和结构均不相同。扫描电镜照片表明，组成多孔氧化硅薄膜的颗粒在占空比增大时变得细腻，并且薄膜整体变得多孔且蓬松。拉曼光谱和红外光谱结果显示，薄膜样品中的非晶硅和Si-H键在较高的占空比下减弱甚至消失。占空比升高时氧化硅桥键所占比例持续增加。

The effect of pulsed plasma duty cycle on the characters of porous silica films

Porous silica films were prepared on the glass substrate by plasma enhanced chemical vapor deposition (PECVD) system modulated by pulse negative bias voltage and silane as precursor gas. During duty cycle increased from 0.162 to 0.864 maintaining bias voltage of deposition region at -350V in the reaction process, the configuration, composition and microstructure of the samples were investigated intensively. The scanning electron microscope (SEM) revealed that the size of silica particles became smaller and silica films got more porous and fleecy when the duty cycle increases. The Raman spectra and Fourier transform infrared spectra (FTIR) revealed that amorphous silicon and Si-H bonds weakened till vanished at higher duty cycle. The proportions of Si-O-Si bridge bonds enhanced while the duty cycle increasing.