MODELING OF CURRENT-VOLTAGE CHARACTERISTICS FOR STRAINED AND LATTICE-MATCHED HEMTS ON INP SUBSTRATE USING A VARIATIONAL CHARGE CONTROL MODEL

A model for the calculation of the current-voltage characteristics of strained In0.52Al0.48As/InxGa1-x on InP substrate High Electron Mobili ty Transistors (HEMT's), based on a variational charge control model, is presented. A polynomial fit of the two-dimensional electron gas (2D EG) density is used for the calculation of the current-voltage charact eristics. The effect of strain is introduced into the 2DEG density ver sus gate voltage relation. Very good agreement between the calculated and measured I-V characteristics was obtained. In addition, our result s show that, for an Indium mole fraction of the InxGa1-xAs channel in the range 0.53-0.60, increasing the Indium mole fraction lowers the th reshold voltage and hence increases the drain current at the same gate bias.