Gas chromatography systems are important analytical tools for a variety of application fields, includine environmental analysis and pollution management. In the last years the demand for using miniaturized portable gas chromatographic systems in hostile locations has grown and much effort has been dedicated to the development of reliable, cost-effective and portable analysis instrumentation [1-3]. Silicon-based technologies are the enabling techniques to realize such miniaturized devices with precision at the micron scale, mass production and integration of detector and other modules. In this work a Silicon micromachined gas chromatograph is presented. The miniaturized device mainly consists of two modules: a.) a silicon micromachined separation column, including inlets/outlet for gas injection system and on-chip housing for the detector; b.) a semiconductor metal oxide detector. A spiral-like column configuration has been designed. Room temperature Deep Reactive Ion Etching (DRIE) and anodic bonding to a Pyrex cover plate have been applied to obtain the Silicon microchannels. The inlets/outlet and the microchamber for the gas sensor have been fabricated on the opposite side of the microcolumn by means of Tetramethyl Ammonium Hydroxide (TMAH) wet etching. A standard gas chromatography procedure has been applied for the stationary phase deposition. Then, a detector consisting of a thick film gas sensor with a polysilicon microheather has been bonded on the top of the outlet by means of a flipchip technique. Finally, the device has been packaged to provide electrical and fluidic connections and preliminary measurements to test the capability of the microcolumn to separate volatile organic compounds have been performed. The proposed microsystem, even if it is at early stage of evelopment, represents a first step for the realization of a highly-integrated, portable and potentially low-cost miniaturized device for gas chromatography applications.
A Silicon Micromachined Gas Chromatograph vor VOC Monitoring
Adami, Andrea;Collini, Cristian;Guarnieri, Vittorio;Lorenzelli, Leandro;Zen, Mario
2004-01-01
Abstract
Gas chromatography systems are important analytical tools for a variety of application fields, includine environmental analysis and pollution management. In the last years the demand for using miniaturized portable gas chromatographic systems in hostile locations has grown and much effort has been dedicated to the development of reliable, cost-effective and portable analysis instrumentation [1-3]. Silicon-based technologies are the enabling techniques to realize such miniaturized devices with precision at the micron scale, mass production and integration of detector and other modules. In this work a Silicon micromachined gas chromatograph is presented. The miniaturized device mainly consists of two modules: a.) a silicon micromachined separation column, including inlets/outlet for gas injection system and on-chip housing for the detector; b.) a semiconductor metal oxide detector. A spiral-like column configuration has been designed. Room temperature Deep Reactive Ion Etching (DRIE) and anodic bonding to a Pyrex cover plate have been applied to obtain the Silicon microchannels. The inlets/outlet and the microchamber for the gas sensor have been fabricated on the opposite side of the microcolumn by means of Tetramethyl Ammonium Hydroxide (TMAH) wet etching. A standard gas chromatography procedure has been applied for the stationary phase deposition. Then, a detector consisting of a thick film gas sensor with a polysilicon microheather has been bonded on the top of the outlet by means of a flipchip technique. Finally, the device has been packaged to provide electrical and fluidic connections and preliminary measurements to test the capability of the microcolumn to separate volatile organic compounds have been performed. The proposed microsystem, even if it is at early stage of evelopment, represents a first step for the realization of a highly-integrated, portable and potentially low-cost miniaturized device for gas chromatography applications.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
