Topography measurement of nano silicon oxide film

Abstract

The Si (111) – 7 x 7 is a semimetal which its surface morphology has been normally studied with using STM (scanning tunneling microscopy) technique, whilst the other kind of silicon, such as Si(100) – 2 x 1 is not a semimetal. For letter surface structure, the AFM (atomic force microscopy) technique can be used as well. There are two main issues which are threatening the use of STM technique as a good technique for studying the silicon surface morphology. First issue is that STM suffers from the impossibility to decouple the anodization bias from the tip – sample separation and second issue is due to heating the sample surface in contact mode. For this purpose, we used AFM technique because it can be applied independently of the feedback and controlled with governing the tip – sample spacing. Moreover, AFM in tapping mode does not touch the sample and can thus eliminate lateral shear forces and overcome tip – sample adhesion forces (e.g. capillarity). In this case, we could grow homogeneous film on the silicon substrate. Key words: Thin Film, silicon dioxide, STM, AFM, surface topography.