Abstract
This thesis presents a novel integration scheme that can fabricate complex micro-nano hybrid silicon structures. The structures are formed by metal-assisted chemical etching, while microlithography and self-assembled diblock copolymer nano- templates are employed to define their geometries. The nano-templates are made of P(S-b-MMA) copolymer that can self-assemble into arrays of 18-nm-diameter PMMA cylinders hexagonally packed in a PS matrix with a lattice constant of 36 nm. To facilitate the self-assembly process, a thin layer of 3-(p-methoxy-phenyl)propyl- trichloro-silane is coated between P(S-b-MMA) and silicon substrate. Once PMMA is selectively removed, the resulting nanoporous PS film is employed to control the deposition of metal nanodots. In the prototype demonstration either chromium or gold is deposited, while chromium and gold is used as the blocking and catalytic material in the etching process, respectively. Meanwhile, photolithography is employed to realize the micro-patterning of metallic thin films. Throughout the process, reactive ion etching is used repeatedly to clean the substrate surface. Finally, the gold-assisted chemical etching is carried out in a solution consisting of deionized water, H2O2, and HF to produce the desired micro-nano hybrid silicon structures. It is demonstrated that the presented integration scheme is a highly repeatable method to form well-aligned, crystalline silicon nanowires with tunable diameters below 100 nm and microstructures as well. As such, the presented integration scheme can fabricate complex micro-nano hybrid structures, which are desired for a variety of cooling and biological applications.