Sidegating effects in inverted AlGaAs/GaAs HEMT

Sidegating effects in submicron gate I-HEMTs are reported over a wide range of the drain voltage. A kink in the drain current and the disappearance of the sidegating effect at high drain voltages (3∼4 V) are attributed to the hole injection caused by the impact ionization in the channel. The observation of a new type of sidegating effect at higher drain voltages (>4 V) is also reported. The strong drain voltage dependence is explained by the enhanced electron injection into the substrate caused by the higher hole injection.