磁控溅射非晶硅薄膜质量的测量

Mass measurement of amorphous silicon thin films by magnetron sputtering

采用射频磁控溅射法沉积了P型非晶硅(a-Si)薄膜,利用X射线衍射仪(XRD)、拉曼光谱仪(Raman)、透射电子显微镜(TEM)分析了薄膜的结构,主要研究了溅射工艺对a-Si薄膜活性物质质量的影响,并通过计算其测量值的不确定度确定了a-Si薄膜活性物质质量的真值范围。结果表明,在磁控溅射镀膜过程中,随着溅射功率的增加,薄膜沉积速率增加;溅射偏压的引入可明显改善薄膜与衬底之间的结合强度,但偏压会在预溅射和沉积过程的初始阶段使金属镍衬底的质量产生一定损耗,且偏压越大其损耗越大,导致a-Si薄膜活性物质质量的测量误差越大。通过优化磁控溅射工艺,当溅射功率为300 W、偏压为50 V、沉积3 h时,可使薄膜与衬底具有良好的结合力,且衬底在预溅射和沉积过程初始阶段的损耗较小。此时a-Si薄膜活性物质质量为0.22 mg,测量不确定度为±0.01 mg,真值范围落在[0.21 mg, 0.23 mg]区间内。电化学分析结果表明,上述a-Si薄膜经气体氢处理后,其在离子液体中具有电化学储氢反应和很高的放电容量(1 682.7~1 759.2 mAh·g^(-1))。

P-type amorphous silicon(a-Si) thin film was deposited by radio frequency magnetron sputtering. And the structure of the prepared film was analyzed by X-ray diffractometer(XRD), Raman spectrometer(Raman) and transmission electron microscope(TEM). The influence of sputtering process on mass of the a-Si film was investigated, and the true value range of film mass was determined by calculating its uncertainty. It was exhibited that the deposition rate of film increased with the increase of sputtering power during the magnetron sputtering process. The introduction of sputtering bias could obviously improve the bonding strength between the film and the substrate. However, the bias would cause a certain mass loss of nickel substrate during the initial stage of pre-splash and deposition process. Moreover, the more mass loss of nickel substrate leaded by high bias pressure would results in the large measurement error in determining the mass of active materials for the a-Si thin film. By optimizing the magnetron sputtering process, the thin film exhibits good adhesion to the substrate, and the substrate loss was small in the initial stage of pre-splash and deposition process when the sputtering power of 300 W, bias voltage of 50 V, and deposition time of 3 h. At this time, the mass for active material of the film was 0.22 mg, the measurement uncertainty was ±0.01 mg, and the range of mass was [0.21 mg, 0.23 mg]. The electrochemical analysis results showed that the a-Si thin film treated with gaseous hydrogen had electrochemical hydrogen storage reaction and high discharge capacity(1 682.7~1 759.2 mAh·g^(-1)) in the ionic liquid.