Abstract

This dissertation deals with the electronic properties of III-V semiconductor alloys. It is focused on the GaInAs system which has become an important material in todays electronic and optoelectronic high-frequency devices due to its superior transport properties. A prerequisite for the realization of those devices is the technological ability to manufacture high-quality pseudomorphic heterostructures using this alloy system on GaAs and InP substrates.

Lattice mismatched epitaxy causes mechanical strain within the semiconductor crystal, which has many-fold influences on the electronic properties and the device characteristics, consequently. Therefore, a major part of the presented work is devoted to the investigation of these strain effects. The dependence of the important semiconductor quantities on the parameters alloy composition, temperature, doping, and strain is studied in a systematic way. In doing so, the aim is on the applicability of the models in numerical device simulation.

Starting with a critical evaluation of fundamental material properties and modeling of those quantities found in the literature, the problem of lattice mismatched epitaxy and the estimation of the critical thickness for pseudomorphic growth is presented. Then, band structure characteristics governing the electronic transport are examined. Deformation potential theory and $\mbox{${\vec{k} \cdot \vec{p}}$}$ method are used to describe band edge energy and effective mass, respectively.

Electron transport, both in the linear ohmic and high field regime, is investigated by means of numerical solution of the Boltzmann transport equation via the Monte Carlo approach, and new improved models for the important parameter electron mobility are deduced. The anisotropic transport behavior parallel and perpendicular to material interfaces, which results from strain effects, are studied in detail. Finally, modeling of the band discontinuities is described since these quantities are essential for heterojunction devices and the influence of strain is still under discussion today.