The authors present a numerical study on electrical methods to measure the source and drain resistances and the effective channel length of state-of-the-art gallium arsenide MESFETs. In particular, the effects of scaling on the physical meaning and gate voltage dependence of the extracted values are investigated. Fringing effects at the gate edges are found to be responsible for a substantial bias dependence of the series resistances, and hence for possible inaccuracies of extraction procedures that overlook such phenomena. A novel extraction technique is also proposed to overcome in part the limitations of conventional approaches.
