Formation and Applications of Silicon-bsased Microporous Structures

• Main Authors: Wei-Ta Hsu, 許偉達
• Other Authors: Hsing-Cheng Chang
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/97232419338557980886

碩士 === 逢甲大學 === 產業研發碩士班 === 97 === Based on microelectromechanical system (MEMS) and electrochemical etching technologies, the research studies the physical properties of micropore structures of silicon that are proved by designing micoresistors and microcapacitors. The advantages of the developed sensor with silicon-based micropore structures are simple process, batch fabrication, low cost, high aspect ratio and high sensitivity. The etchant concentration and background illumination are arranged to understand the variation of electrochemical etching process. The denser the etching solution concentration gets, the deeper the etching depth obtains but disfavored branches also obtain. Low etchant concentration is poor to etch silicon bulk because of the electropolished state dominant. Illumination intensity can increase current density that transfers etching process to electropolished state to enhance a lateral etching. The weak illumination reduces current density to rough etched surface and a vertical structure can not be performed without illumination assisted. The depth of microstructure was about 82 μm by etching for 2 hours and the rate of etching was about 0.35 μm/min. The aluminum was deposited on the microstructure as electrodes and measured by a LCR meter. The average capacitance density measured at low frequency was 5.85 nF/cm2. The capacitance of microstructures increased with decreasing the operation frequency.