Temperature-dependent interface evolution for Ti/GaAs(100) and Cr/GaAs(100)

We have investigated the temperature-dependent formation of the 15-Å Ti/GaAs(100) and 15-Å Cr/GaAs(100) interfaces in the range 20≤T≤360 °C using high-resolution x-ray photoemission and ${\mathrm{Ar}}^{+}$ bombardment. These results show the physical distributions of Ga and As and their varying chemical states. Experimental results reveal that both Ti and Cr react with As and that Ga is dissolved in the evolving metal matrix. Quantitative analysis indicates that the amount of disrupted GaAs substrate is 8.1 and 9.6 Å for Ti/GaAs and Cr/GaAs at 20 °C, respectively. Annealing at 200≤T≤360 °C leads to further reaction and substrate disruption. A correlation between the concentration of Ga in the metal overlayer and the Ga binding energy is provided by sputter depth profiling.