Several practical issues in the fabrication and high-temperature operation of micro suspended heating structures compatible with standard CMOS technology are reported. Suspended microstructures are fabricated in a standard CMOS process and are released by post-process silicon etching. Addition of 15 vol/00 of isopropyl alcohol (IPA) to 25-wt/100 tetra-methyl ammonium hydroxide (TMAH) is found to greatly increase yield of the post-process release etch. Electrothermal properties of the polysilicon are investigated during high-temperature operation. Significant thermally induced drift (reduction) in resistance At high temperatures is found, and the impact on temperature control is discussed. Thermal isolation is found to be about 50 K/mW, and reliable operation Is observed at a temperature estimated to be around 1000deg.C.
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