Electronic properties of pseudomorphic InGaAs/AlGaAs (on GaAs) and InGaAs/InAlAs (on InP) Modfet structures

Abstract

Pseudomorphic (strained channel) modulation doped field effect transistors (MODFETs) have recently received a considerable amount of attention. These devices provide potential for both improved device performance and new physics studies. In this paper we present theoretical studies of n-type and p-type strained channel MODFETs. Information on carrier masses, subband occupation, and the charge control picture as a function of strain in the channel is presented. The n-MODFET studies are based on using the results of tight binding calculations for bandstructure in the strained channel. The p-MODFET problem involves the use of the Kohn Luttinger hamiltonian. Self consistent solution of the Schrodinger equation and the Poisson equation then allows us to study the MODFET properties. In p-type MODFETs, the control of heavy hole-light hole coupling via strain allows the possibility of tailoring hole masses. Comparisons with some of the experimental works previously published are also presented.