Temperature-dependent reaction and buried-interface movement for Ti/GaAs(100) and Cr/GaAs(100)

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Abstract
The effects of temperature on interface reactions for the Ti/GaAs(100) and Cr/GaAs(100) systems have been studied using x-ray photoemission. Analysis of semiconductor core-level binding-energy shifts indicate that both Ti and Cr induce reaction with the GaAs substrate at 20 °C, and that this reaction can be enhanced with thermal treatment at relatively low temperatures. A quantitative method is presented to calculate the retreat of the buried interface due to reaction. At room temperature, the total disruption of the substrate is found to be 8.1 Å for Ti/GaAs and 9.6 Å for Cr/GaAs. At 360 °C, this increases to 18.5 Å for both systems. An activation energy of substrate disruption of 0.13 eV is obtained for both Ti and Cr overlayers. Information about the Ga redistribution in the metal overlayer is obtained from the change of the total Ga 3d signal.