Abstract

Epilayer design for the MODFET is frequently performed using the depletion approximation [1,2]. The work of authors such as Ponse et. al. and Stern and Das Sarma have provided tools by which electron distributions and capacitances can be calculated without this assumption [3,4]. They demonstrate that for two dimensional electron gas (2DEG) sheet concentrations significantly below the saturation saturation value, free and bound electrons are present in the supply layer. Because these electrons must be modulated with the 2DEG electrons, the gate capacitance is increased while the transconductance is decreased [5]. The unity current gain frequency, f_T, is thus decreased.

© 1987 Optical Society of America