Drain-to-source current for high gate voltages in AlGaAs/GaAs heterostructure FET's (HFET's) is found to depend on the electron saturation velocity in the AlGaAs layer. A simple model, which takes into account the current through the undepleted channel in the AlGaAs layer as a function of the electron saturation velocity in AlGaAs, is proposed for describing I-V characteristics of HFET's for high gate voltages. Using the model, effective electron saturation velocity in AlxGa1_xAs for different Al content levels has been obtained from the analysis of the present experimental results; 7 × 106 cm/s for x = 0.24 and 3 × 106 cm/s for x = 0.3 at a 4 × 1017 cm-3 doping concentration.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering