A detailed study of the effect of water percentage on different characteristics of anodic silicon dioxide thin films

Silicon dioxide (SiO₂) exhibits distinctive characteristics over other insulating materials such as easy synthesis, excellent insulating property, well established synthesis techniques, ease of patterning and highly selective to silicon in tetramethylammonium hydroxide (TMAH) solution, etc. Although SiO₂ can be synthesized by several growth and deposition based techniques, anodic oxidation of silicon offers some unique advantages such as oxide synthesis at room temperature, simple and low cost of experiment set-up, no involvement of toxic and expensive gases, etc. In the present work, anodic oxidation of silicon is employed to deposit SiO₂ films, the effect of water percentage on different properties of as-grown oxide films is investigated in detail. Various characterization tools such as ellipsometry, scanning electron microscope (SEM) and atomic force microscopy (AFM) are employed for characterizing different properties of as-grown oxide films. In the present study it is observed that the oxide films deposited in low concentration of water (≤ 2.7 vol%) added electrolytes are uniform, smooth and compact. (author)