Subthreshold and above threshold gate current in heterostructure insulated gate field-effect transistors

Experimental data are presented which show that the gate current at zero drain bias in HIGFETs changes qualitatively when the gate voltage is varied from below to above threshold. Above threshold, the gate current flows from the entire channel, and below threshold, the gate current flows from the gate edges. A new independent method for deducing threshold old voltage is introduced.