Progress on Distributed Resistance Model for pHEMT

With increasing scale and complexity in pHEMT circuit and dimension shrinking in unit pHEMT devices, distributed effects are becoming more crucial than ever. During the design of amplifiers, precise prediction of the resistances of a device is vital to the simulation result due to the direct impact on impedance. This work reports a set of experiments utilizing different testing structures to reveal how a pHEMT device’s layout affects its gate-to-source/drain resistances due to distribution of resistance along electrodes and the consequent current crowding. As an example, a distributed resistance model of source-side gate bar is quantitatively analyzed. It is shown that the prediction of the model coincides with the measurement data obtained from a variety of testing devices with different numbers of gate fingers.