520.495/580.495 Microfabrication Laboratory
Laboratory Assignment #10
Prelab:
Propose a series of experiments to characterize experimentally the performance of your sensor. Hints: You will need to make some pressure measuruments to find the sensitivity of the sensors.
Laboratory work:
Carry on the experiments that you have defined in your prelab.
Postlab:
The purpose of the final report is for you (i) to reinforce your understanding of how our microfabricated pressure sensor was constructed, and (ii) to compare the design and fabrication of our device to "state of art" microfabricated pressure sensors. We would like the report to follow the format of a technical article, with the major sections described below.
Introduction: Survey the literature (the journal Sensors & Actuators is a good place to start) and address the following questions.
What are the applications for microfabricated pressure sensors?
What are the principles of operation?
How are they made (e.g. bulk vs. surface micromachining)?
Experimental: Describe the process used to fabricate the sensor, in sufficient detail that a knowledgeable in microfabrication could reproduce your work. Include figures to illustrate the cross-section of the sensor at each step in the process.
Results: Since we may not be able to test the response of the completed sensors by the time this is due, use this section to report on the measurements made during the fabrication process, such as diaphragm thickness and aluminum thickness. Use the measured resistances on the large devices at the edge of the wafer to estimate the sheet resistance of the boron diffusion, and aluminum metallization. (If some of these devices did not work on your wafer, we'll supply you with values from wafers that did.)
Discussion: Compare your sensor to one of the "state of the art" sensors you found during your literature search. Address factors such as design (size, complexity), fabrication (number of mask levels, processes/materials used), and performance (refer back to the articles handed out at the beginning of the semester to estimate the response of your sensor).
Conclusions/Future Work: Your recommendations for improvements in the design and fabrication of the sensor will be welcome.