A theoretical determination of impact ionization induced gate current in InP HEMTs

A theoretical calculation of the gate current in InAlAs/InGaAs/InAlAs HEMTs, which include both the thermionic and tunneling components of the hole current due to impact ionization and the electron Schottky current, is reported. The hole current is a strong function of the ionization coefficient and the gate-bias dependent hole transmission probability. The theoretical gate current is in excellent agreement with experimental data.