Improved design of the gallium arsenide permeable base transistor

The permeable base transistor (PBT) was first reported by Bozler et al. (1979). Using numerical techniques, an analysis was conducted of the standard GaAs PBT in order to predict the high-frequency performance of the device. The device geometry was altered by changing the ratio of the gate-electrode-finger width to the gate-finger spacing, keeping a fixed channel width. It was found that the narrow-finger device gave marginally improved gain. Calculations were conducted regarding the contributions of the different sections of the device structure to the input capacitance of the PBT. The procedure employed in the investigation involved the solution of the Poisson and current continuity equations for the electric potential and the quasi-Fermi potential at every node in the device grid structure.