The gate currents of junction field-effect transistors at low temperatures

Abstract

The gate currents of Ge and Si junction FET's operating beyond pinch-off show a component which increases as the temperature decreases and increases rapidly with drain voltage. A model is presented which explains these currents in terms of impact ionization by majority charge carriers, accelerated to energies above 1 eV in the high field region of the pinched-off channel. The probability of carriers reaching these energies is thought to be determined by their interactions with the lattice and thus is a function of lattice temperature, carrier type, and semiconductor material.