Heat tolerance of titanium boride and titanium nitride contacts to gallium arsenide

For contacts prepared from titanium boride and nitride ion-plasma sputtering onto gallium arsenide, both formation mechanisms and thermal stability were investigated using a combination of structural, secondary-emission, optical, and electrophysical methods. A physical model for contact formation was proposed according to which B(x)Ga(1-x)As (GaN(x)As(1-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. (Author)