A unified small-signal theory of uniform-carrier-velocity semiconductor transit-time diodes

Assuming a uniform carrier velocity, a unified small-signal description can approximate the behavior of divers transit-time diodes. Application is made to diodes with optimized conductive cathodes. A comparison of the "diffusion" noise behavior of saturated-and unsaturated-velocity diodes is made. For similar material parameters, the latter is better. However, using holes in silicon in the first instance, and electrons in gallium arsenide in the second, the saturated-velocity silicon device is superior.