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AUTOMATED MEASUREMENT OF SEMICONDUCTOR DEVICE CHARACTERISTICS FOR COMPUTER-ASSISTED ELECTRONIC DESIGN Mustafa G. Guvench University of Southern Maine Abstract This paper describes two new techniques that facilitate measurement of input, output and transfer characteristics of semiconductor devices in an instructional electronics laboratory for the purpose of determining their SPICE parameters for computer-assisted electronic design. The techniques utilize standard features of GPIB controlled digital multimeters and waveform generators to do the simultaneous measurement of current and voltage. They are affordable because only one meter is required to collect the terminal i-v data. One of them also allows true common-terminal measurements, i.e., common-emitter, common-source, etc. The techniques have already been tested and incorporated into the junior electronics laboratory experiments at the University of Southern Maine. 1.INTRODUCTION Acceptance of SPICE in the electronics industry as the standard tool for simulating electronic circuits, its recent migration into the electrical engineering curricula through new textbooks[1-4] and educational software[5,6], ABET requirement to emphasize "design experience" in the undergraduate engineering programs and wider utilization of electronic design automation tools in the electronics industry have created a need to give the electrical engineering student a better understanding of and experience with semiconductor device characterization and modeling. SPICE is a very powerful circuit analysis and simulation tool and constitutes the core of most computer aided circuit analysis/design packages. However, just like any system simulation program, the closeness of its predictions and the actual response of a system is ultimately limited by the accuracy of the model parameters it is supplied with as well as how good the models are. Inaccuracy or inadequacy of the model parameters supplied for the components of the circuit cannot be corrected by the simulator. Understanding of SPICE modeling of components such as resistors, capacitors and sources does not require much beyond a background in linear circuit theory. However, understanding, measurement, and proper utilization of semiconductor device models in SPICE requires a higher level of background. The latter, if not handled at the proper time in the electrical engineering curriculum, may lead to frustration with and misconceptions about electronic circuit simulations and design verifications done with SPICE. Ideally, SPICE models should be readily available for the off-the-shelf semiconductor devices. Unfortunately, spec sheets supplied by semiconductor component manufacturers have not kept up with electronic design automation. Either the information they contain is incompatible with the more sophisticated SPICE models [9] or the tolerances of the parameters they give are so loose (like -50% to +100% around a typical value) that they render no value for the cycles of ... View Full Document

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