Chromium and Iron Determination in GaAs Epitaxial Layers

Abstract

The characteristics of gallium arsenide metal semiconductor field effect transistors (MESFET’s) are mainly determined by the interface region between the epitaxial layer and the Cr-doped GaAs semi-insulating substrate. A nimber of adverse effects associated with this interface are eliminated and device performances are improved by the insertion of a high resistivity buffer layer between the substrate and the active layer. It has also been suggested that more reliable results can be obtained by doping the buffer layer with a low concentration of deep level elements such as chromium or iron for compensating the residual donor or acceptor levels.