OBSERVATION OF THE INSTABILITY OF TIXGAY ALLOYS WITH RESPECT TO GAAS AT ELEVATED-TEMPERATURES

The metallurgical reactions occurring at the Ti-GaAs interface between 600 and 850-degrees-C were examined using Auger depth profiling. Between 600 and 720-degrees-C titanium will react with gallium arsenide to form a uniform Ti(x)Ga(y)/TiAs/GaAs layered structure, similar to that which formed upon annealing Ti-GaAs contacts at much lower temperatures [J. Vac. Sci. Technol. A 5, 1511 (1987); J. Vac. Sci. Technol. A 6, 1473 (1988)]. However above 800-degrees-C the dominant reaction products are a titanium arsenide phase and liquid gallium. This result has significant implications for the development of thermally stable contacts to gallium arsenide using titanium-based metallizations.