A SILICON PROBE WITH INTEGRATED MICROHEATERS FOR THERMAL MARKING AND MONITORING OF NEURAL TISSUE

This paper describes a microheater structure and its integration on a silicon microprobe, The 30-mu m-diameter microstructure can he used to heat local areas of tissue or to measure local tissue temperature wit h an accuracy of <0.3 degrees C. The polysilicon microheater is suspen ded on a dielectric membrane to reduce undesired heat conduction to th e probe substrate, The heating efficiency is 4.4 degrees C/mW in still water and 2.2 degrees C/mW in guinea pig cortex, Six milliwatts appli ed for 2 min in cortex produces a temperature of 50 degrees C, creatin g a well-defined 50-mu m-wide lesion for determining probe position hi stologically. Fabrication of the heaters requires no additional maskin g or processing steps in addition to those normally used for recording or stimulating probes.