A Study Of Charge Control In n- And p-type Lattice Matched And Strained Channel MODFETs With GaAs And InP Substrates

A general charge control model has been developed to understand the performance of n-type and p-type MODFETs with strained active channels. The effects of strain on material properties are modeled via a tight binding formalism for n-type devices and the Kohn Luttinger hamiltonian for p-type devices and the resultant parameters are used within a self consistent solution of the Poisson equation and the Schrodinger equation. The effect of strain on carrier masses, sheet charge density, and subband occupation are discussed. Some experimental results on the strained n-type InGaAs/InAlAs (on InP substrate) MODFETs are also presented.