A treatise on the capacitance—Voltage relation of high electron mobility transistors

Abstract

A new model for the capacitance-voltage relation of a HEMT is presented. The model uses three physically motivated capacitive terms in series. The <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C(V)</tex> expressions are derived using the quantum mechanical triangular potential well model and the two-dimensional electron-gas charge-control model. These expressions provide further physical insight into the AlGaAs heterosystem. The results obtained should be readily applicable to such techniques as DLTS and other <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C(V)</tex> interface measurement methods. The equations derived will also serve as a basis for analytical and circuit modeling of HEMT structures.