A two-dimensional analytical model of homojunction GaAs BMFET structures

The first analytical model of a GaAs-based Bipolar Mode FET (BMFET) device is presented. As a result of a reduced epilayer thickness, the bipolar operation of this class of devices is strongly affected by the transverse path of the drain current underneath the gate, which causes the gate region to be partly debiased. In this article a gate crowding model valid for such a device topology is proposed and then applied to develop an analytical model of the device. Comparison with experimental and numerical results shows clearly that the gate crowding causes a focusing of the drain current in the channel, which, in turn, leads the active area to depend strongly on bias conditions. The results demonstrate the potentiality of this model for an accurate prediction for influence of the geometrical and physical parameters on device performance. Copyright (C) 1996 Elsevier Science Ltd