A surface micromachined capacitive pressure sensor for biomedical applications

Rochester Institute of Technology (RIT) and The Department of Pediatric Cardiology, at Strong Memorial Hospital, have joined efforts to work on a research project funded by National Institute of Health (NIH). The goal of this research project was to design and develop a semiconductor pressure sensor, sensitive to small pressure changes within an embryonic chicken heart. A capacitive pressure sensor design was chosen and fabricated to replace the complicated electronics currently being used for pressure measurements in these fetal heart research studies. In addition to the fabrication of the mechanical sensor, an electronic circuit was developed which provided amplification of the capacitance measurement, as well as converting the pressure varying capacitance to a frequency modulated signal. Although a fully integrated chip has not been successfully completed, data has been collected that shows a frequency response verses pressure.