Correlations between electrical properties and interfacial reactions for cobalthyphen;germanium contacts tonhyphen;type GaAs

摘要

Correlations between the electrical properties and interfacial reactions for the Co/GaAs, Co/Ge/GaAs, and Ge/Co/GaAs contact systems have been studied. Currenthyphen;voltage and capacitancehyphen;voltage measurements show that for all three systems following heat treatments at temperatures not higher than 400thinsp;deg;C, a rectifying contact was obtained. However, annealing in the temperature range of 450ndash;600thinsp;deg;C leads to an ohmic behavior; the lowest contact resistivity value (2.7times;10minus;4OHgr;thinsp;cm2) was obtained for Co/Ge/GaAs following heat treatment at 500thinsp;deg;C. The electrical properties of the contacts are correlated with modifications in the structure and composition of the metallization interfacing the GaAs as determined by Auger electron spectroscopy, transmission electron microscopy, and xhyphen;ray diffraction.