The Effect of Plasma Gas Composition on the Nanostructures and Optical Properties of TiO2 Films Prepared by Helicon-PECVD
The Effect of Plasma Gas Composition on the Nanostructures and Optical Properties of TiO2 Films Prepared by Helicon-PECVD
复制标题
DOI：
10.1142/s1793292018501242
复制
发表时间：
2018-10
期刊：
影响因子：
1.2
通讯作者：
D. Li;S. Dai;A. Goullet;A. Granier
中科院分区：
文献类型：
--
作者：
D. Li;S. Dai;A. Goullet;A. Granier
采用Helicon-PECVD技术，在浮置电位（[Formula：see text]）或衬底自偏压（[Formula：see text]）为50[Formula：see text] V的条件下，利用氧/四异丙醇钛（TTIP）等离子体在低温下沉积了TiO 2薄膜。通过控制由其自身的蒸气压引入的TTIP流速来施加低钛分压（[TTIP] [式：见正文] 0.013[式：见正文]Pa），而通过使用载气（CG）增加流速来形成更高的钛分压。然后获得前体分压[TTIP[式：见正文]CG] [式：见正文]Pa和0.093[式：见正文]Pa。在[式：见正文]下，所有的膜都显示出柱状结构，但是不均匀性的程度随着前体分压而降低。已经证明了从无定形（[TTIP] [式：见正文] 0.013[式：见正文]Pa）到无定形（[TTIP[式：见正文]CG] [式：见正文][式：见正文]Pa）的相变，因为等离子体中的O[式：见正文]离子与中性通量的比率降低并且膜中含有更多的碳。然而，在[公式：见正文]50[公式：见正文]V的情况下，不同前体分压的相关生长速率略微降低（[公式：见正文] 15%）。在[TTIP] [公式：见正文] 0.013[公式：见正文]Pa下的柱状形态已变为颗粒状结构，但在[TTIP[公式：见正文]CG] [公式：见正文][公式：见正文]Pa和0.093[公式：见正文]Pa下仍观察到均匀的柱状。在[TTIP] [公式：见正文][公式：见正文]Pa下生成金红石相。对在[式：见正文]50[式：见正文]V下沉积的膜进行椭圆偏振测量;结果表明，从低水平到高水平的前体添加导致折射率降低。
TiO2 films were deposited from oxygen/titanium tetraisopropoxide (TTIP) plasmas at low temperature by Helicon-PECVD at floating potential ([Formula: see text] or substrate self-bias of [Formula: see text]50[Formula: see text]V. The influence of titanium precursor partial pressure on the morphology, nanostructure and optical properties was investigated. Low titanium partial pressure ([TTIP] [Formula: see text] 0.013[Formula: see text]Pa) was applied by controlling the TTIP flow rate which is introduced by its own vapor pressure, whereas higher titanium partial pressure was formed through increasing the flow rate by using a carrier gas (CG). Then the precursor partial pressures [TTIP[Formula: see text]CG] [Formula: see text][Formula: see text]Pa and 0.093[Formula: see text]Pa were obtained. At [Formula: see text], all the films exhibit a columnar structure, but the degree of inhomogeneity is decreased with the precursor partial pressure. Phase transformation from anatase ([TTIP] [Formula: see text] 0.013[Formula: see text]Pa) to amorphous ([TTIP[Formula: see text]CG] [Formula: see text][Formula: see text]Pa) has been evidenced since the O[Formula: see text] ion to neutral flux ratio in the plasma was decreased and more carbon contained in the film. However, in the case of [Formula: see text]50[Formula: see text]V, the related growth rate for different precursor partial pressures is slightly ([Formula: see text] 15%) decreased. The columnar morphology at [TTIP] [Formula: see text] 0.013[Formula: see text]Pa has been changed into a granular structure, but still homogeneous columns are observed for [TTIP[Formula: see text]CG] [Formula: see text][Formula: see text]Pa and 0.093[Formula: see text]Pa. Rutile phase has been generated at [TTIP] [Formula: see text][Formula: see text]Pa. Ellipsometry measurements were performed on the films deposited at [Formula: see text]50[Formula: see text]V; results show that the precursor addition from low to high levels leads to a decrease in refractive index.