Effect of doping profile variations on the performance of the permeable base transistor

The cutoff frequency ftand maximum frequency of oscillation fmaxof the permeable-base transistor have been calculated for devices with a fixed geometry and different doping profiles to determine the profile that gave the highest value of The effect of different static velocity-field curves for GaAs and InP, and associated diffusion-field dependencies on device performance have also been examined. The results of the simulations show that the saturated velocity for GaAs PBT\´s has a major impact on performance. The uniformly doped device, Ndof 4 × 10¹⁶cm^-3, has a higher when the saturated velocity is larger, but the effect of the low field mobility is small. The InP device has a slightly higher than the corresponding GaAs devices at this doping level. The 20-10-4 × 10¹⁶cm^-3devices have the highest of all the GaAs devices investigated.