Modeling of quantum effects in ultrasmall HEMT devices

Numerical simulation of ultra-submicrometer high electron mobility transistors based upon a set of quantum moment equations is presented. These provide a first quantum description, based upon the moments of the Wigner distribution function. In HEMTs, the conduction electrons are confined in a narrow conduction channel and the short gate lengths (and small aspect ratio) create different potential barriers across the conduction channel than in a long-channel situation. In these small structures, quantum effects are expected to be prominent. A substantial change in the electron density distribution is found to occur due to the inclusion of these quantum corrections, and the total current in the simulated devices is increased by as much as 10% for a 240-nm gate-length device