Micro-hotplate

J.S. Suehle, R.E. Cavicchi, M. Gaitan, and S. Semancik. Tin oxide gas sensor fabricated using CMOS micro-hotplates and in-situ processing , IEEE Electron Device Letters 14 (1993), 118-120. 

D. Briand, A. Krauss, B. van der School, U. Weimar, N. Barsan, W. Gopel, and N.F. de Rooij. Design and fabrication of high-temperature micro-hotplates for drop-coated gas sensors . Sensors and Actuators B68 (2000), 223-233. 

F. Udrea, J.W. Gardner, D. Setiadi, J.A. Covington, T. Dogaru, C.C. Lua, and W.l. MUne. Design and simulations of SOl-CMOS micro-hotplate gas sensors . Sensors and Actua-torsB78 (2001), 180-190. 

R.E. Cavicchi, J.S. Suehle, K.G. Kreider, M. Gaitan, and P. Chaparala. Optimized temperature-pulse sequences for the enhancement of chemically specific response patterns from micro-hotplate gas sensors , Sensors and Actuators B33 (1996), 142-146. 

T.A. Kunt, T.J. McAvoy, R.E. Cavicchi, and S. Semancik. Optimization of temperature programmed sensing for gas identification using micro-hotplate sensors . Sensors and Actuators B53 (1998), 24-43. 

D. Briand, S. Heimgartner, M.A. GretiEat, B. van der School, and N.R de Rooij. Thermal optimization of micro-hotplates that have a silicon island. . Journal of Micromechanics and Microengineering 12 (2002), 971-978. 

P. Ruther, M. Ehmann, T. Lindemann, and O. Paul. Dependence of the Temperature Distribution in Micro Hotplates on Heater Geometry and Heating Mode , Proc. IEEE Transducers 03, Boston, MA, USA (2003), 73-76. 

S. Muller. CMOS-Micro-Hotplate with MOS Transistor Heater for Integrated Metal Oxide Gas Sensors, Diploma thesis, ETH Zurich, Switzerland (2002). 

D. Barrettino. Graf, S. Taschini, S. Hafizovic, C. Hagleitner, and A. Hierlemann. A singlechip CMOS micro-hotplate array for hazardous-gas detection and material characterization , Proc. IEEE International Solid-State Circuits Conference (ISSCC), San Francisco, CA, USA (2004), 311-312. 

U. Frey, M. Graf, S. Taschini, K.-U. Kirstein, C. Hagleitner, A. Hierlemann, and H. Baltes. A Digital CMOS Micro-Hotplate Array for Analysis of Environmentally Relevant Gases , Proc. IEEE European Solid-State Circuits Conference (ESSCIRC), Leuven, Belgium (2004), 299-302. 

For reasons of fouling or deactivation, it may be desirable to be able to replace immobilized enzymes in time, and for this a programmable way of adsorption and release of enzymes would be very welcome. An example of this is the use of a 4nm thin polymer film that can be thermally switched between a hydrophilic (swollen) state at 20 °C and a more hydrophobic protein-adsorbing (collapsed) state at 48 °C, integrated into a micro hotplate with fast heating options so that a protein monolayer can be adsorbed and released within 1 s (Huber et al., 2003). 

Optimize micro-hotplate based H2 sensor design and fabrication processes... 

Investigate the use of alternative micro-hotplate geometries to increase power density and reduce heat loss... 

Designed new micro-hotplates for low voltage (5 V), low power (5 mW) operation... 

Figure 1. SEM Photo of a Released Micro-Hotplate Thermal Isolation Stmcture...

Figure 2. Schematic of Functional Layer Stack on a Micro-Hotplate Platform...

Llohet, E., Brezmes, J., lonescu, R., Vilanova, X., Al-Khahfa, S., Gardner, J.W., Barsan, N., Correig, X. Wavelet transform and fuzzy ARTMAP-hased pattern recognition for fast gas identification using a micro-hotplate gas sensor. Sens. Acmators B 83, 238-244 (2002) MaUat, S. A theory for multiresolution signal decomposition the wavelet representation. IEEE Trans. Pattern Anal. Mach. Intell. 11, 674-693 (1989)... 

It then addresses the micro-hotplates concept that has led to the development of different types of micromachined gas sensor devices. The different reahzations of micromachined semiconductor gas sensors are presented thin- and thick-film metal-oxide, field effect, and those using complementary metal-oxide semiconductors (CMOSs) and silicon-on-insulator (SOI) technologies. Finally, recent developments based on gas sensitive nanostructures, polymers, printing and foil-based technologies are highlighted. 

Key words silicon micromachining, micro-hotplates, semiconductor, metal-oxide, field-effect, gas sensors, CMOS and SOI, nanowires, printing, polymeric, plastic. 

Figure 6.3 illustrates the heat losses that occur in a micro-hotplate when operating. The thermal energy, Q, generated by the Joule effect in the microheater, is given by ... 

Micro-hotplates are made using a combination of thin-fihn and silicon micromachining processes. There are two main kinds of micromachined silicon substrates closed-membrane and bridge-membrane. They consist of a suspended thin dielectric membrane, made of silicon nitride and/or silicon oxide, that is released using silicon micromachining on either the obverse or... 

Table 6.1 Comparison of various micro-hotplate designs that have been reported in the literature... 

The dielectric membrane of the micro-hotplates will be composed of CMOS dielectric films. It can be formed through a silicon micromachining post-process either on the back or the front. 

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