EFFECT OF DOPING PROFILE VARIATION ON THE PERFORMANCE OF THE PERMEABLE BASE TRANSISTOR.

The cutoff frequency f//t and maximum frequency of oscillation f//m //a //x of the permeable base transistor have been calculated using a drift-diffusion model, for GaAs and InP devices with a fixed geometry and different doping profiles and different static velocity-field curves. The uniformly doped device, N//d equals 4 multiplied by 10**1 **6 cm-**3 , has a higher f//m //a //x when the saturated velocity is larger, but the effect of the low field mobility is small. The InP device has a slightly higher f//m //a //x than the corresponding GaAs devices at this doping level. The uniform 10**1 **7 cm-**3 device, the 4-10-4 multiplied by 10**1 **6 cm- device, and the 20-10-4 multiplied by 10**1 **6 cm-**3 device have the highest f//m //a //x of all the GaAs devices investigated.