Fabrication Of Silicon Based Micro And Nano Devices

Micro-nano structures exhibited lots of novel characters,which traditional materialsdo not have.Nanotechnology has become one of the most popular research areas.The increase of integration level depends on the further miniaturization of the micro-nano devices,The improvement of micro-nano processing technology is the basis for device size reduction.Micro-nano processing technology can be classified into three categories:planar process,probe process and model process.Planar process refers totransferringpatterns from photolithography mask to the substrate surface to form a complex structure of micro-nano devices by etching or deposition.The main process included lithography,etching,film deposition and so on.The probe process not only refers to the use of conventional probes(scanning electron microscopy probes,atomic force microscopy probes)to manufacture micro-nano devices on the substrate surface,but also the use of non-solid probe,such as focused ion beams,laser beam.The model process refers to the use of micro-nano-scale molds to reproduce the corresponding nanostructures,such as nano-imprinting.The main contents of this dissertation are as follows:1.The formation of convex surface and tips of silicon materials by KOH solution:Silicon anisotropy was studied.The formation mechanism of needle tip was studied by crosssectional and plan-view SEM.The crystal facets during the anisotropy etching was identified to be {311} plane family by SEM images and also the geometry calculation.The etching rate of the {311} plane is about 0.6 ?m/min.Silicon tipswith {311} inclined crystal facetswas also obtained with 1.7:1,aspect ratio.The radius of curvature of the silicon tip was about 100 nm.2.The manufacture process of SiO2 microdisk cavity by KOH etching was studied.The morphological characteristics of SiO2 microdisk were characterized by SEM,and the hems of microcavity was wedge-shaped,which was beneficial to the quality factor.The tapered optical fiber was coupled with the micro-disc cavity to obtain transmission spectrum.The Q value of the microcavity was calculated to be about 1 × 104 and the FSR was 9.6 nm.The total roughness of the microcavity was 395 nm deduced by Q value.The roughness of the microcavity was mainly caused by the side wall and the lower surface.3.The difficulty of making the eight-step microlens array lied in the alignment of photoetching and ICP.In this dissertation,we optimized the photolithography and ICP processes to fulfill the complicate structure.The microlens wafer was finally thinned to be only 50?m with circle aluminum aperture on the backside.The diffraction efficiency of our microlens was measured to be 86%.