Applications Of Focused-ion-beam/Focused-electron-beam Technology On The Fabrication Of Nanodevices

As an important method of fabricating micro/nanostructures and devices with a collection of multi-function such as deposition/etch/irradiation,Focused Ion Beam/Focused Electron Beam(FIB/FEB)technology has been widely used in constructing nanoscale electronic devices,optical devices,optoelectronic devices,and biological fluid components,etc.This technology can flexibly and controllably fabricate three-dimensional(3D)micro/nano structures and devices with the nanometer resolution.Besides,with the development of the 3D electrical device and the third generation of wide bandgap semiconductor materials,research has been made on applying wide-bandgap-semiconductor nanostructure to 3D micro/nanodevices,which will impove integration and overcome the limitations of silicon-based semiconductors for optoelectronic device and high-frequency high-power devices/applications.In this dissertation,3D nanodevices,especially the 3D diamond ultraviolet(UV)detector and 3D gate-all-around diamond Field Effect Transistor(FET),were fabricated and realized by using deposition,etch and irradiation of the FIB/FEB technology.And we explored the mechanical property of nanowires,which can be used as free-space interconnects in 3D devices.That shows FIB/FEB technology has effective and controllable advantages on the fabrication of the 3D nanodevices.The dissertation consists of the following 3 chapters.Firstly,we systematically studied the electrically induced vibration phenomenon of the platinum(Pt)nanowires fabricated by Focused Electron Beam Induced Deposition(FEBID)technology.For the first time we determined the Young's modulus and density of them.Futhermore,we studied how the Young's modulus changes with the variation of the diameter of Pt nanowires.Based on its features of small mass and high Young's modulus,Pt nanowires were used successfully to detect extra mass preliminarily as basic resonant units.Secondly,the nanodiamond cones were fabricated utilizing gray-scale patterns with FIB etching.The field emission properties and the influence of the UV light on the as-formed cones had been explored in the double probe scanning electron microscopy.It can be summarized that the as-formed nanocones with higher slicing numbers,due to its higher content of sp~2 amorphous carbon surfaces,showed a higher emission current and ultra-low turn-on field V=1.3 V/cm,in addition,twice higher emission current was achieved by UV illumination.It is proved that the FIB etching can be used as an effective method to realize the processing of sp~2 carbon/diamond hybrid system.Finally,stress-induced nanowires were fabricated by FIB irradiation methods,and used as free-space interconnects in the 3D gate-all-around diamond FET.The electrical performance of 3D gate-all-around diamond FET was preliminarily evaluated.The fabrication method is suitable for the large area processing of the device,and it lays the foundation for the fabrication of high frequency high power FET for integrated circuits in the future.