EFFECTS OF SCREENING ON THE 2-DIMENSIONAL ELECTRON-TRANSPORT PROPERTIES IN MODULATION-DOPED HETEROSTRUCTURES

The effects of screening on the polar optical phonon scattering rates and on the transport properties of the two-dimensional electron gas in AlGaAs/GaAs modulation doped heterostructures have been investigated through Monte Carlo simulations incorporating the three valleys of the conduction band, size quantization in the Gamma valley and the lowest three subbands in the quantum-well. At typical sheet densities observ ed in modulation doped field-effect transistors, screening considerabl y affects the electron transport properties under moderately large fie lds and at low temperatures, by lowering the intrasubband polar-optica l phonon scattering rates especially in the first subband. The results show that screening, which is usually ignored in device Monte Carlo s imulations, should be included in the simulation in order to be able t o predict the device performance correctly. (C) 1998 Elsevier Science Ltd. All rights reserved.