| The semiconductor industry has been achieving great developments recent years under the direction of the Moore's law. With the further scaling of electronic device feature size, sillicon-based field effect transistor will approach its physical limitation soon. Graphene is a promising alternative to become the main semiconducting material for next generation for its exercellent properties, such as high mobility, ballstic transportion and high thermal conductivity, etc. Large amount of research on its basic properties, preparation, applicatons, especially as the channel conducting material in logic devices, have been studying since its discovery in 2004. However, there are still several main obstacles standing on the road to various applications, such as preparation of large area and high quality graphene, bandgap engineering, and device parasitic parameters.The main conclusions are as follows:1. We prepared graphene by mechanical exfoliation method and chateriaed it using optical microscopy, Raman and atom force microscopy. Then, we fabricated graphene field effect transistors, including back gate and top gate configuration, and characterized their electrical performance.2. We used Al2O3 as the top gate dieletric to simplify and optimize the fabrication process. Al film was deposited through electron beam evaporation(EBE) and followed oxidation process in the atmosphere. This method is benefitical for several points such as the good adhesion between film and graphene, little damage to graphene lattice and a relatively high ratio of Ion and Ioff of transistors.3. We analysed the factors that affect the metal-graphene contact resistance and put forward a new device structure of single-layer channel and multi-layer contact(SCMC) which could reduce the contact resistance not only benefited from the resistance reduction by edge contact, but also had the potential to inherit the considerable bandgap in top gate transistors with single layer or bilayer graphene channel. |
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