Atomic Force Microscopy Field-induced Oxidation on SOI substrates and Formation of Nickel Silicides on Silicon Nanowires

• Main Authors: Shang-Wu Liu, 劉尚武
• Other Authors: Hsun- Feng Hsu
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/45834898106846933894

碩士 === 國立中興大學 === 材料科學與工程學系所 === 100 === Recently, the size of electronic devices approaches to limitations of Moore''s law. One dimension nanostructures, such as nanotubes and nanowires, are attractive building blocks for nanoelectronics due to their unique photoelectric properties. Metal silicides have excellent electric properties in nanoscale, and they have very low barrier height on the valence band of silicon. Moreover, nickel silicides are promising materials for applying in the nanoelectronic devices because of their low Si consumption and thermal stability. Scanning probe lithography can operate in air and fabricate nanostructure simply. Using reactive deposition epitaxy (RDE) can promote the epitaxial growth of metal silicide on silicon. We expect that it can be used in the formation of multiple Ni-silicide/Si heterostructures. In this study, Si oxide nanowires were fabricated on SOI substrates by AFM field induced nanooxidation in a tapping mode with pulse modulation method. Further, the thin Si nanowires were fabricated by a selective wet etching. Furthermore, the effects of reaction temperature and deposition rate on the formation of silicide were studied. The results show that the height and width of oxide dots were proportional to the oxidation time, and the oxidation rate was about 1.5 nm/ms. When the oxidation time was longer than 1 ms, the size of oxide dots did not increase. Controlling the oxidation time as 1 ms and modulating the turn off time can be used to fabricate high-aspect-ratio oxide nanowires. Si nanowires with 35 nm in diameter were formed after selective wet etching process. Epitaxial NiSi2 was formed on the Si nanowires at 300 and 350 ℃ because NiSi2 has a small lattice mismatch with Si. In addition, NiSi2 preferred to form on the (111) surface because (111) surface was more rough than (100) surface. Decreasing the deposition temperature and increasing the deposition rate caused the increase of the nucleation density of NiSi2. Multiple nanostructure of NiSi2/Si was formed when more Ni atoms deposited.