Rangel Rita C C, Cruz Nilson C, Rangel Elidiane C
Laboratory of Technological Plasmas (LaPTec), São Paulo State University (UNESP), Science and Technology Institute of Sorocaba (ICTS), Av. Três de Março, 511, 18087-180 Sorocaba, Brazil.
Materials (Basel). 2019 Dec 19;13(1):25. doi: 10.3390/ma13010025.
The possibility of controlling the density of organosilicon films was investigated by tuning the plasma activation degree without providing extra energy to the structure, as usually reported in the literature. For this purpose, thin films were deposited in plasmas fed with hexamethyldisiloxane/Ar mixtures at a total pressure of 9.5 Pa. The power of the radiofrequency excitation signal, , ranged from 50 to 300 W to alter the average energy of the plasma species while the electrical configuration was chosen to avoid direct ion bombardment of the growing films. In this way, it was possible to evaluate the effect of P on the film properties. Thickness and deposition rate were derived from profilometry data. X-ray energy dispersive and infrared spectroscopies were, respectively, applied to analyze the chemical composition and molecular structure of the layers. Surface topography and roughness were determined by atomic force microscopy while nanoindentation was used to evaluate the mechanical properties of the films. From electrochemical impedance spectroscopy the total resistance to the flow of electrolyte species was derived. The main alteration observed in the structure with changing P is related to the proportion of the methyl functional which remains connected to the Si backbone. Chain crosslinking and film density are affected by this structural modification induced by homogeneous and heterogeneous plasma reactions. The density increase resulted in a film with hardness comparable to that of the silica and more resistant to the permeation of oxidative species, but preserving the organosilicon nature of the structure.
与文献中通常报道的情况一样，在不给结构提供额外能量的情况下，通过调节等离子体活化程度来研究控制有机硅薄膜密度的可能性。为此，在总压力为9.5 Pa的六甲基二硅氧烷/氩气混合气体等离子体中沉积薄膜。射频激发信号的功率(P)在50至300 W范围内变化，以改变等离子体物种的平均能量，同时选择电气配置以避免生长中的薄膜受到直接离子轰击。通过这种方式，可以评估(P)对薄膜性能的影响。厚度和沉积速率由轮廓测量数据得出。分别应用X射线能量色散光谱和红外光谱来分析各层的化学成分和分子结构。通过原子力显微镜确定表面形貌和粗糙度，同时使用纳米压痕来评估薄膜的力学性能。从电化学阻抗谱得出对电解质物种流动的总电阻。随着(P)的变化，在结构中观察到的主要变化与仍与硅主链相连的甲基官能团的比例有关。链交联和薄膜密度受均相和异相等离子体反应引起的这种结构改性的影响。密度增加导致薄膜硬度与二氧化硅相当，并且更耐氧化物种渗透，但保留了结构的有机硅性质。
