PACS 73.40.Ns, 68.60.Dv

For contacts prepared from titanium borides by and nitrides ion-plasma sputtering onto gallium arsenide both formation mechanisms and thermal stability were investigated. We used a combination of structural, secondary-emission, optical and electrophysical methods, such as electronography, X-ray diffraction, atomic force microscopy, Auger electron spectroscopy, secondary-ion mass spectrometry, taking photoluminescence spectra and I - V curves. A physical model for contact formation was proposed. According to it, BxGa1-xAs (GaNxAs1-x) solid solutions are formed at the phase interfaces when titanium borides (nitrides) are deposited. The defects are produced in the semiconductor near-surface regions during heterostructure formation and further heat treatment. The correlation between the physico-chemical interactions at contact interfaces and the contact electrophysical parameters occurs through these defects. The objects of our investigation demonstrated high thermal stability. This was due to their two-layer structure formed by components having well-pronounced antidiffusion properties. As a result, the interdiffusion processes at the phase interfaces are drastically weakened.

Keywords: metal - semiconductor contacts, titanium borides, titanium nitrides, thermal stability.